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Service Manual Maintenance of Wheel Loader Electrical

1. Oil pressure gauge of transmission Represent the pressure of hydraulic oil in shift control system This gauge often classifies into two types The oil pressure gauge of transmission configured on exported vehicle usually hasn t red or green areas but the oil pressure gauge of transmission configured on domestic vehicle usually has red and green areas 1 Oil pressure gauge of transmission without red and green areas When the pointer is in the range of 13 17 x 100kPa or 18 85 24 65 x 1OPSI the pressure of oil is normal Stop to check when pointer 1s in the other areas 2 Oil pressure gauge of transmission with red and green areas When the pointer is in green area the pressure of oil is normal Stop to check when pointer is in the other areas Braking barometer Represent the pressure of air in braking system This indicator often classifies into two types The braking barometer configured on exported vehicle usually hasn t red or green areas but the braking barometer configured on domestic vehicle usually has red and green areas 1 Braking barometer without red and green areas When the pointer is in the range of 4 8 x 100kPa or 5 8 11 6 x10PSI the pressure of air 1s normal Stop to check when pointer 1s in the other areas 2 Braking barometer with red and green areas When the pointer is in green area the pressure of air is normal Stop to check when pointer is in the other areas Fuel level
2. 3 Working schematic diagram of head and back light The four lights on the ceiling of cab are defined as head lights and back lights The two lights on the back cover are defined as taillights The switch of interior trimming light is provided itself The detailed information of taillight and work light can refer to the attachment rocker switch information Schematic diagram Refer to Figure 5 2 and 5 3 The basic principle and maintenance of system fault are mostly similar to headlight circuit and don t explain here 5 3 Circuit of steering light Schematic diagram Refer to Figure 5 1 Introduction of main components 1 The substance and installation position of combined switch can refer to Figure 5 4 and 5 5 The switch of steering light is realized by part of functions of combined switch The color of three using pin conductors is grey yellow and white respectively The grey conductor connects with steering flashing power No 33 conductor and yellow conductor connects with left turn signal wire No 6 conductor and white conductor connects with right turn signal wire No 7 conductor 55 Maintenance Manual of Loader Electrical Equipment Figure 5 4 Combined switch Figure 5 5 Installation position of combined switch 2 Flash relay SG252 The three pins of flasher are defined as B power terminal connect with No 21 conductor L flashing signal output terminal connect with No 33 conduct
3. Fel level Rough filtration alam switch Ernkig barometer Pak briking switch Oilpressme switch ea SersOl LeMperatire sensor SeMso4r Figure 3 1 The schematic diagram of instrument and alarm system 3 2 Explanation of main parts Take 958 as example 3 2 1 Instrument panel assembly Figure 3 2 Instrument panel 46 Maintenance Manual of Loader Electrical Equipment The instrument panel assembly includes engine water thermometer fuel level gauge braking barometer speedometer oil temperature indicator of torque converter variable oil pressure gauge and working hour meter seven instruments in all Several alarm indicator lights are all luminous diodes and they supply necessary warn when whole vehicle is in the running state 3 2 2 Temperature sensor The vehicle sets two temperature sensors to monitor the oil temperature of torque converter and water temperature of engine The temperature sensor is equal to thermistor and the resistance of it becomes smaller as the temperature increases Room temperature 26 226Q 115 C 26 4Q Figure 3 3 Shape of temperature sensor Figure 3 4 Oil temperature indicator of torque converter 3 2 3 Braking barometer Figure 3 5 Internal structure of braking barometer The deformation of patch beryllium hydrogen copper is caused by pressure variation thus lead to the resistance pointer inner sensor slip and change the magnitude of current to realize the swing of instrument
4. The rectifier is generally six tubes bridge full wave 35 Maintenance Manual of Loader Electrical Equipment rectification 1 When the DC voltage acts on the both ends of excitation winding the current will generate magnetic field Under the driving of generator the magnetic field rotates following the rotor Under rotating magnetic field the three phase symmetrical winding will generate three phases sine electromotive force with same frequency and amplitude and the phase contrast is 120 2 Rectify using the unidirectional conductivity At any instant only the positive diode connecting with the highest potential winding conducts also only the negative diode connecting with the lowest potential winding conducts repeated cycle like this six diodes conduct in turn to gain a stable pulsating DC voltage between two ends of loader 3 The terminal voltage of generator is proportional to speed of generator The speed range of generator is so big that the terminal voltage of generator changes in a large range That can t meet the requirement that electrical equipments on the transfer machine should use constant voltage So the constant voltage regulator must be set oe ae ra Figure 2 15 Schematic diagram of generator 4 The constant voltage regulator changes the magnitude of excitation current by make and break of switch tube which change the magnetic field to stable the voltage of generator 5 The filter capacitor can filte
5. and connects with No 60 29 Maintenance Manual of Loader Electrical Equipment conductor c The functional gear figure of this electric lock is shown in the above table Explanation O stands for turning on for example if turn the power to ON gear B B2 connects with M d The method in judging whether the electric lock is destroyed disconnect the connection of No 121 28 and 60 conductors with electric lock and then remove the electric lock from vehicle and check with 200 ohm grade of digital multimeter according to the following table 2 08081 10000 type electric lock ordinary vehicle type See in Figure 2 3 a The electric lock has B BR R1 R2 C and ACC six pins in all b B pin is power pin and connects with No 21 conductor BR pin is firing pin and connects with No 28 conductor R2 pin is starting pin and connects with No 22 conductor c The functional gear figure of this electric lock is shown in the above table Explanation O stands for turning on for example if turn the power to ON gear B BR connects with ACC d The method in judging whether the electric lock is destroyed disconnect the connection of No 21 22 27 28 and 92 conductors with electric lock and then remove the electric lock from vehicle and check with 200 ohm grade of digital multimeter according to the following table Notice If the vehicle starts successfully the driver loosens the key of electric lock and the
6. braking and out of shifting function When driver steps on the foot braking pedal or puts down the emergency braking button electronic control box detects the signal and then control the speed change operating valve to cut off the power of transmission Brake at the same time cut off the power output of transmission utilization of 22 Maintenance Manual of Loader Electrical Equipment braking and out of shifting function to improve the efficiency of braking Meanwhile protect the transmission and transmission system and also increase the utilization ratio of engine and work efficiency of working devices Braking and out of shifting function only plays a role in process or reverse first and second gear When the loader is in the high speed gear the electronic control box can not cut off the power of transmission to ensure the driving safety Notice When fault occurs in speed change operating system of vehicle please disassemble the speed change operating system without authorization If the barrier can not be removed please contact with the special maintenance station or after service company When work or drive normally please select the driving power cutting function otherwise affect the braking performance shorten the life of braking system and transmission system 6 Self protection of system with failure Electronic monitoring box monitors continuously input signal from speed change operating handle and speed sensor and also t
7. deadweight so that improve work efficiency Bucket stable limit device The device is made up of proximity switch on scoop cylinder refer to Figure 4 3 and electromagnet coil on pilot control valve There is a red indicator light on the proximity switch When red light indicates the state of proximity switch and there is dislocation between shrinking rod and proximity switch the proximity switch closes and then red light is lightened and black output line transmits ground signal If driver pushes joystick to final end when bucket is in the angle of loading magnet force generating by electromagnet coil can catch the bucket joystick now the driver can loosen his hand and the bucket joystick can t spring back to neutral position The bucket will always collect back until the proximity switch closes to shrinking rod The proximity switch is broken red light distinguishes electromagnet coil loses power and magnet force disappears Then the bucket joystick springs back to neutral position automatically under dead weight The bucket stops at the leveling position and doesn t collect back any more 51 Maintenance Manual of Loader Electrical Equipment Figure 4 2 Boom and proximity switch Figure 4 3 Bucket shrinking rod and proximity switch 4 3 Maintenance of system fault Check whether 10A fuse is fusing Check whether every connector connects well Check the clearance between metallic object and proximity switch no more
8. electrical system of whole vehicle will be damaged Il Start switch Maintenance Manual of Loader Electrical Equipment Start switch also called electrical lock is classified into four gear positions 1 Auxiliary Plug in the key of start switch and then turn one gear position anticlockwise The gear position is automatic reset after loosening it can turn to OFF gear automatically This gear position hasn t used at present 2 OFF In this gear position oil way of engine is cut off to stop and the power control circuit of whole machine is cut off As to export vehicle except alarm lamp other lamps such as indoor lamp headlight front side lamp taillight back side lamp working lamp and all indicator lights on the instrument panel can t be lightened All lights of other vehicles can t be lightened Notice Only in this gear position can plug in or draw out the key of start switch 3 ON Plug in key of start switch then turn to the first gear position clockwise When in this gear position the electrical system of whole vehicle can work normally 4 START Plug in key of start switch then turn to the second gear position clockwise In this gear position starting motor can work to start the engine After engine starting successfully please loosen key of start switch immediately This gear position isn t self holding and after loosening the start switch turns to the ON gear of start switch autom
9. lamp fuse and No 21 conductor 2 Turn on the electric lock turn electric lock to ON then the B B2 terminal 2l Maintenance Manual of Loader Electrical Equipment connects with M No 121 conductor connects with No 28 conductor So the current conducts through No 28 conductor connector CN1 and coil of battery relay to ground Notice regard No 0 line as ground line in all loaders from our company don t repeat again in the following text After conducting electricity to battery relay contact switch then turns on so connect No 56 conductor with No 2 and 2a conductor The voltage conducts through No 2 conductor to flameout relay contact starting relay contact and each channel fuse in the twenty channels fuses box Then the voltage arrives to all loaders of electric equipments in the whole vehicle 3 Turn the electrical lock to starting START gear Connect B B2 terminal G2 terminal S terminal and M terminal with each other Turn on the No 121 conductor No 60 conductor and No 28 conductor As to the vehicle with electronic control transmission if the gear shifting handle is in the neutral gear the controller outputs 24V voltage to the coil of starting linkage intermediate relay through No 59 conductor The starting linkage intermediate relay gains electricity and the contactors close Turn on the No 60 conductor and No 22 conductor and then the current conducts through No 22 conductor and coil of to ground So the contactors of
10. lead wire of high gear armature and low gear armature the black conductor is reset line the blue conductor is another brush lead wire of high gear armature the white conductor 1s another armature lead wire of low gear armature After opening electric lock the No 37 conductor gains electricity 24V If the wiper switch the detailed information can refer to the attachment information of rocker switch is in gear pin 37 connects with pin 25 and motor runs in low gear If the wiper switch is in II gear pin 37 connects with pin 26 and motor runs in high gear If turn off the wiper switch gear becomes OFF gear pin 24 connects with pin 25 and the current conducts through No 25 conductor pin 24 of wiper switch low gear armature ground because wiper doesn t stop in initial position at the instant of closing the switch Explain There is an automatic stopping device inside to make sure that the wiper can stop in initial position all the time When wiper is in initial position the reset wire connects with ground 7 2 Maintenance of common fault 7 2 1 Wiper motor doesn t work 1 Check whether the 10A fuse is fusing 2 Check whether the switch of wiper is destroyed 3 Check whether the connector is loose and whether there is wear on the wiring harness 4 Check whether the wiper motor armature 1s short circuit or open circuit 7 2 2 Nozzle doesn t spray water 1 Watch whether the motor ru
11. lines please be sure to break this switch for safety 2 3 Example for maintenance of system common faults Take LG958 electrical apparatus as example 2 3 1 Maintenance of power system common faults Whole vehicle no electric Fault Feature Fault Reason Treatment Method Turn on the electric lock Anode switch doesn t close Close anode switch don t listen to the sound Anode switch is destroyed Replace anode switch of power relay closing Capacity Loss of battery seriously Charge again or replace battery and then the electrical apparatus loads of Fusing of 10A electric lock fuse Replace 10A fuse E E exams ine Sia ae switch of luminaire the Terminals of battery line are Check the four wiring pile heads lamp doesn t lighten loosen of storage battery wiring contact when operating the of battery and battery wiring switch of windshield terminal of anode switch and wiper the windshield fasten again wiper doesn t move Connectors of wiring harness are Connect the connectors etc loosen again Other reasons Make corresponding treatment 43 Maintenance Manual of Loader Electrical Equipment 2 3 2 Maintenance of power system common faults Turn off electric lock but engine doesn t stop and whole vehicle still has electricity Fault Feature Fault Reason Treatment Method After turning off the electric The contacts of power relay are Replace power relay lock the electrical a
12. pointer See Figure 3 5 47 Maintenance Manual of Loader Electrical Equipment 3 2 4 Fuel level sensor The fuel level sensor is actually discrete slide resistance The resistance reduces as oil level rising It is installed on the fuel tank 3 2 5 Alarm pressure switch The whole vehicle sets two pressure switches which are brake low pressure alarm and low oil pressure alarm The specific installation position is shown in the following figure Figure 3 6 brake low pressure alarm switch Figure 3 7 low oil pressure alarm switch When the braking pressure is lower than 0 45MPa and oil pressure is lower than 0 08MPa alarm indicator light both indicates to warn 3 3 Example for maintenance of system common faults Take exported type 958 with Kangmingsi1 as example 3 3 1 Abnormal indication of thermometer Remove the sensing wires on the temperature sensor down The oil and water temperature of torque converter correspond to No 15 and 14 conductor respectively If the sensing wires connect with ground the instrument will show full scale If the sensing wires hang in the air the instrument will show minimum scale Then we can judge the instrument and circuit are good If the sensor is destroyed replace the sensor Otherwise check the circuit If the circuit is good there is fault in the instrument 3 3 2 Abnormal indication of fuel level Remove the sensing wire No 19 conductor of fuel level sensor If the sensing wires conne
13. rear light controls the left and right rear light on or off simultaneously The position of rear light is shown in the Figure 1 10 3 Switch of backlight lamp Switch of backlight lamp controls front and rear clearance lamps four lamps in all wane switch backlight and instrument backlight lamp on or off 4 Switch of working lamp Switch of working lamp controls working lamps on the ceiling of cab on or off simultaneously The position of working lamp is shown in the Figure 1 6 There is a backlight lamp on each wane switch When switch of backlight lamp is in the closing state indicating lamp of switch turns on and vice versa 1 Wane type switch of front light 2 Combination type switch of front light combine with steering switch Figure 1 11 Switch of front light The position of switch of front light is shown in Figure 1 11 The switch of front light has three gear positions far light close light and closure V Semi automatic operating system suitable for electronic transmission Semi automatic operating system is made up of speed change operating handle electronic control box speed change operating electromagnetic valve and emergency Maintenance Manual of Loader Electrical Equipment braking button The operation of system is very safe and simple because of using special microprocessor intelligent control system The system also has the functions of neutral gear locking interlock protection of neutral gear and starting
14. than 8 10mm generally Check whether proximity switch is destroyed Open the electric lock When metallic object is approaching the red light is lightened the black output line should connect with ground by measuring with multimeter Check the pilot coil The resistances of three pilot coils are all about 100 200Q 52 Maintenance Manual of Loader Electrical Equipment CHAPTER V LIGHTING SYSTEM 5 1 Circuit of front combination lamp 5 1 1 Schematic diagram The schematic diagram take LG958 as example is shown in Figure 5 1 Combined switch T Headlamp close light A far light ertaki AE Lon a8 65 86 a rn 123458 1 b O 0 O 9 Q es 5 a rm ry i Figure 5 1 The schematic diagram of front combination lamp steering lamp and alarm lamp circuit 5 1 2 Explanation of principle After opening the electric lock the 10A headlight fuse in twenty channels fuses box gains electricity 24V and conduct through No 44 conductor to combination switch meanwhile conduct through No 35 conductor to the contact of front combination lamp far and close light relay When combination switch is broken both No 49 conductor and No 50 conductor don t gain electricity and left and right lamps don t work When combination switch in the state of far light or close light the No 49 or 50 conductor gains electricity 24V and front combination lamp far and close light relay gains electricity When the contact close
15. the speed As to forward first and second gear turn to corresponding reverse gear directly at any time namely 1 F lt gt 1R and 2F lt gt 2R As to forward third and fourth gear turn to corresponding gear after reducing the speed loosen the throttle 4 Downshifting forcibly function KD key In the Figure 1 16 the direction of arrow is the operating direction When the gear is set on the forward second gear or the reverse second gear please put down the button of downshifting forcibly KD key on the speed change operating handle then the gear of transmission can shift to forward first gear or reverse first gear automatically Once shift to other gears the function of downshifting forcibly stops automatically Release the function of downshifting forcibly in the following methods Put down the downshifting forcibly key KD key again Change the driving direction Rotate the handle to shift gear The function combined with direct reversing function to make shifting gear frequently convenient when the loader shovels and loads materials For example the loader drives in the speed of forward second gear When near to the materials put down the KD key downshift to forward first gear automatically After loading materials completely shift to reverse gear again then shift to reverse second gear automatically So the loader drives backward in speed of second gear to improve work efficiency 5 Power cutting function
16. 73 conductor Never make a faulty connection Otherwise the silicon diode will be burn out and then lead to worse fault 2 2 5 3 The method to judge whether the generator generates electricity normally 37 Maintenance Manual of Loader Electrical Equipment and treatment measures 1 Check with the DC voltage 200V of multimeter Open the electric lock to measure the terminal voltage of generator connect red pen with D of generator and connect black pen with ground and record the reading of multimeter the reading is actually the terminal voltage of storage battery usually less than 26V Start the loader measure the terminal voltage of generator again and record the reading of multimeter the reading is about 28V if generator works normally The latter reading should be higher than the former one 2 If generator doesn t generate electricity Firstly check whether the driving belt of generator is too loose Close the electric lock and check whether the wire connecting terminals of generator connect wires correctly tightly and reliably with wrench Check whether the grounding of generator is reliable If still can not work out a solution to the problem please contact with the maintenance service of Lingong or diesel engine manufacturer 2 2 6 Starting motor The starting motor is general kit diesel engine It is made up of electromagnetic switch direct current motor forked plectrum and transmission gear The starting motor conv
17. ON IN MAINTENANCE OF LOADER ELETRICAL EQUIPMENT Wererere irre TT eee ere Te re re ee 6 1 1 Operating specification and points for attention in maintenance of electrical system 6 1 2 The using method of digital multimeter SRR 8 1 3 The basic circuit knowledge of engineering machinery lt 1 sts esteeeetseieeeeee eet eeen 9 1 4 Points for attention and marginal data in maintenance of electrical appliance 77 12 CHAPTER ll THE PRINCIPLE OF POWER SYSTEM rere rere rere erie rT eer ert ie ee 27 2 1 The explanation of principle E E E E sa seetereetes 27 2 2 The introduction of main components EVENE EE E EEEE E EEEE EEN EE E EAT E aa 29 2 2 1 Electric lock E E E E E E ee Oe eee ee 29 2 2 2 FUSetteeeeereereeeseereseeeeresreseeeeeeseeseeeseeseresroseoesreseceereseeserorreseeescoseoeeresreseresresererreeeeesrenee 30 2 2 3 Relay Wa Wot E b v WoW bv 9 0 Wb WAG 6 Win 6 s ie d 6 aie 094 Wie 8 e 6H GO e Ola SNe G86 6 WET 8 E OS oo be Hoe 31 2 2 3 1 Intermediate relay JD2914 E T er E E A T 31 2 2 3 2 Battery relay E E E eee ee ISTE ee Eee 32 2 2 3 3 Starting relay and flameout relay snd Gista eiel wide E wiatele Nb Salers wed seb E a E 33 2 2 4 Flameout electromagnet only part of vehicle type aca aaleia 6a Bata wasted EE Oe Siew s Glas Sane e 34 2 2 5 Generator E a a E E E T N 35 2 2 5 1 The principle of generator Pr E T E E eer re eee 35 2 2 5 2 The connection method of Weichai generator used in LG953 06ers 37 2 2 5 3 The method to judge whether the gen
18. Service Manual E Maintenance of Wheel Loader Electrical Equipment SHANDONG LINGONG CONSTRUCTION MACHINERY CO LTD Maintenance Manual of Loader Electrical Equipment Maintenance of Wheel Loader Electrical Equipment SHANDONG LINGONG CONSTRUCTION MACHINERY CO LTD Address Lingong Industry Park Linyi Economic Development Zone Shandong china Tel 86 539 8785597 Fax 86 539 8785618 Email service sdlg cn Website http www sdlg cn Maintenance Manual of Loader Electrical Equipment Service Manual Concise Guide All reasonable steps have been taken to ensure that this publication is correct and complete but should any user be in doubt about any detail clarification may be sought from Shandong Lingong construction machinery Co Ltd or their accredited representative The information in this document is subject to change without notice and should not be construed as commitment by Shandong Lingong construction machinery Co Ltd Shandong Lingong construction machinery Co Ltd accepts no responsibility for any errors that may appear in this document Shandong Lingong construction machinery Co Ltd P R China All rights reserved The contents of this publication may not be reproduced in any form or communicated to a third part without prior written permission of Shandong Lingong construction machinery Co Ltd Maintenance Manual of Loader Electrical Equipment CHAPTER I POINTS FOR ATTENTION AND BASIC INFORMATI
19. ack wipers and the control switch is at the lower right of cab foreground 1 Wiper switch on the front window The wiper switch on the front window has three gears stop low speed and high speed The wiper in the stop position can reset automatically 2 Washer switch on the front window install on some vehicle type Figure 1 18 Wiper switch Figure 1 19 Washer switch 25 Maintenance Manual of Loader Electrical Equipment Put down the switch of washer and the washer begins working to inject water in kettle on the windowpane The switch of washer can reset automatically after loosening and then the washer stops injecting water 3 Wiper switch on the back window install on some vehicle type The wiper switch on the back window has two gears stop and run The wiper in the stop position can reset automatically Check frequently whether the water in kettle is running out to avoid cleaning the windowpane without water and leading to visual intrusion When the environmental temperature is lower than 0 C discharge the kettle to empty or inject into the antifreeze otherwise the kettle can not work because of icing over and even frozen to be bad 11 Spare socket Spare socket is a power interface of DC 24V and the maximum power is 200W VI Retreat alarm system Figure 1 20 Backing car alarm The backing car alarm is in the back cover of engine shown in Figure 1 20 When the speed change operating handle is in the
20. al of Loader Electrical Equipment by mistake will lead to unexpectable fault from fuse fused to fire of whole machine When unplug the connector please hand the body of connector and push the lock catch of connector to separate to two directions and grasp the conductor to unplug directly is not allowed When connect the connector make sure watch the connector whether it is locked otherwise please connect again until the lock catch is locked When maintaining the connectors of waterproof water mustn t enter into the inside of connector otherwise connect again after drying Use circuit detecting instrument correctly 1 When using each circuit detecting instrument firstly understand the working principle and using condition prohibit using improperly 2 When measuring voltage and electric current select proper measuring range to avoid destroying the instrument 3 Prohibit measuring voltage in the position of electric current and resistance Understand the circuit principle diagram The principle diagram is the relationship diagram of each component in the electrical system when they are working normally Understand the function of each component in circuit and the effect of occurring fault until you spell over the principle diagram so judge the fault phenomenon correctly and quickly Avoid disassembling blindly to save maintenance time Understand the meaning of ground correctly The negative electrode of storage battery is groun
21. atically Notice Before starting engine please confirm the anode switch turn on and speed change operating handle in neutral position The time of starting engine is not more than 10 seconds The time between two starting operations is 30 seconds at least and the times of starting continuously can t more than three times If more than three times start again after cooling starting motor and flameout electromagnet sufficiently otherwise the using life of storage battery will reduce and cooling starting motor and flameout electromagnet may be destroyed UI Instrument assembly Horn switch The monitoring instruments alarm system and steering indicating system of loader are all assembled on the instrument assembly under steering wheel Instrument system 13 Maintenance Manual of Loader Electrical Equipment can display oil temperature of torque converter cooling water temperature speed change oil pressure fuel position oil pressure of engine braking air pressure speed emergency braking alarm service braking low voltage alarm whole vehicle working hours counter left and steering lamps and etc 18 items in all The above instruments and alarming contents will change according to different vehicle type and configuration 1 Monitor instrument Take export vehicle 958 and domestic vehicle 953 as example other vehicle type is basically same 958 instrument assembly is made up of 7 instruments and 953 instrument assembly is mad
22. ay to form current by connecting positive and negative electrode of power and electrical equipments with conductors 1s called circuit or loop II Ohms law In circuit the current is proportional to voltage and inversely proportional to resistance which is called ohms law Express with equality Current I Voltage U Resistance R Single lead type and Negative ground In industrial power supply system connect the metal shell of electrical equipment with zero line of power system which 1s called protective zero terminating The purpose is that cut off the power rapidly when connect live wire of electrical equipment with ground Prevent high voltage from applying on the electrical equipment to harm personal safety Connecting metal shell of electrical equipment with ground is called protective earthing terminating When the insulator of electrical equipment is destroyed or there is electric on the shell conduct the current into earth by protective earthing wire to protect personal safety The above earth and zero terminating are both protective measurements Using electricity in vehicle and engineering machinery is absolutely different from the earth or zero terminating which mentioned above We usually connect cathode of storage battery with electrical equipment and connect anode with frame that is to say metallic frame body instead of one conductor in the circuit The circuit formed in the method is called single lead type At present l
23. bout 549 There is a contact between two big bolts The working principle of contactor is shown in the Figure 2 11 When there is certain current conducting through the coil the two contacts conduct When coil is broken the two contacts are broken 32 Maintenance Manual of Loader Electrical Equipment The method in judging whether the contactor is destroyed Measure with the resistance gear of multimeter the resistance between two small bolts is about 54Q the resistance between two big bolts is infinite Connect cathode of DC 24V power with one small bolt and connect anode with the other small bolt and then the two big bolts should conduct with each other 2 2 3 3 Starting relay and flameout relay Figure 2 12 Installation position of starting relay and flameout relay only take 956 as example The two relays are the same type and both of them are short term working The installation position is shown in Figure 2 12 The contactor has four terminals There is a coil between two small bolts and the resistance is about 26Q There is a contact between two big bolts The working principle of relay is mostly similar to battery relay The difference is the two contacts of the relay are semi spherical shape The method in judging whether the relay is destroyed Measure with the resistance gear of multimeter the resistance between two small bolts is about 26Q the resistance between two big bolts is infinite Connect cathode of DC 24V powe
24. ce Manual of Loader Electrical Equipment If no electricity check the storage battery storage battery line and anode switch If the voltage of contact 1 is normal make sure that the faults of starting motor itself lead to start failure Further detect as follow Turn the electric lock to START gear to check the voltage of contact 2 on starting motor If no electricity the electromagnetic switch has fault and replace it If the voltage 1s normal the direct current motor has fault and replace starting motor assembly 2 2 7 Storage battery 6 QW 120B also call battery Figure 2 19 Series connection of two storage batteries The whole vehicle uses series connection of two VARTA or other storage batteries The anode of first storage battery connects with ground crossing power switch or connect with ground directly Connect cathode with the anode of storage battery and connect the cathode of second storage battery with starting motor and storage battery relay See the Figure 19 The storage battery is reversible DC power and parallel connection with generator to supply electricity for electrical equipment The storage battery can supply 200 600A starting current for starting motor in a short time 5 10S The storage battery 1s equal to large capacitance and can absorb the voltage appearing in the circuit to protect electric components from breakdown Warning Please don t close to the storage battery with open fire to avoid explosion War
25. ct with ground the instrument will show full scale If the sensing wires hang in the air the instrument will show minimum scale Then we can judge the instrument and circuit are good If the sensor is destroyed replace the sensor 48 Maintenance Manual of Loader Electrical Equipment Otherwise check the circuit If the circuit is good there is fault in the instrument 49 Maintenance Manual of Loader Electrical Equipment CHAPTER IV AUTOMATIC RESET SYSTEM Used combined with pilot control 4 1 Schematic diagram The schematic diagram is shown in Figure 4 1 0 7 9 Floating 4 NMEN electromagnetic valve A 69 Loy Bucket to Pg PAT TT peoromameti valva Boom 64 AAN electromagnetic valve Proximity switch boom Load NPN normally closed N C Figure 4 1 The electrical appliance diagrams of automatic reset system 4 2 Explanation of system function Boom lifting limit device The device is made up of magnet and proximity switch installed on the boom refer to Figure 4 2 and electromagnet coil on the pilot control valve There is a red indicator light on the proximity switch When the indicator light is far away from metal induction object the proximity switch closes and red light is lightened The black output line transmits ground signal to electromagnetic coil in the pilot control valve If the driver pulls the boom joystick to the end the magnetic circuit closes The magnetic force generated b
26. ctromagnet lose magnetic and the boom joystick bounces back to the neutral position under the effect of reset spring then the boom doesn t lift no longer Boom floating device When push the boom joystick to extremely front position boom joystick is catch by boom floating electromagnet now the driver can lose hold and the boom joystick doesn t bounce back to neutral position At the moment boom is in the state of floating Pull the boom bar back to neutral position to release the boom floating state When operate the boom to lower push the boom joystick to floating state and then the boom drops under the effect of dead weight At the moment the right hand can carry out other operations for example put the bucket horizontally to increase the work efficiency Push the boom joystick to the floating position when carry out the shoveling and loading operation So the bucket fluctuates with the ground to avoid the damage to ground No matter what state is the vehicle in confirm there is no any barrier or person around the vehicle before carrying out the operation of boom and bucket Otherwise lead to the damage of device and casualty Bucket level limiting space device 24 Maintenance Manual of Loader Electrical Equipment If the bucket is in the condition of unloading push the bucket joystick to the extremely back position and the bucket electromagnet is catch by bucket tilt back keeping electromagnet to keep in the extrem
27. d Negative electrode ground is often employed in construction machinery that is to say connect the negative electrode of storage battery on the body of complete appliance including the metallic conductor connecting frame with cab So the complete appliance also is ground when it is connected with the negative electrode of storage battery When detect the voltage and resistance of one check point the red pen of multimeter connects with the check point and the black pen connects with any position of complete appliance body Notice There is no paint oil or dust Bind the wiring harnesses and conductors correctly 1 Never fold or bend the wiring harness with strength 2 Keep away from moving components to prevent snapped or worn 3 Prevent the friction against sharp angularity of metal 4 Keep away from oil and water as possible as you can 5 Keep away from the position with 7 Maintenance Manual of Loader Electrical Equipment high temperature as possible as you can for example the body of engine If there is wear on the conductors and wiring harnesses bandage and replace them immediately and fix the wiring harness in safe place Use the fuse rightly When replacing the fuse the fuse with same specification must be used When it is emergency copper wire can t be used The fuse used in this product should accord with the relevant regulation in the QC T420 Fuse Used in Vehicle So if the fuse should be replaced please use
28. direct reversing downshifting forcibly automatic power cutting and self protection of system with failure i Common operation Figure 1 12 speed change operating handle The speed change operating handle lies under the steering wheel Put the handle back and forth refer to the arrow in the Figure 1 12 to operate the vehicle to process handle in the position of F and draw back handle in the position of R handle in middle position is neutral gear handle in the position of N Emergency braking button is near to the right of seat refer to the Figure 1 13 When put down the button the vehicle is in the state of emergency braking Pull the button up to release emergency braking Position of second gear Figure 1 13 Park emergency braking button Figure 1 14 Shifting operation of speed change gear the position of gear 2 is shown in figure 20 Maintenance Manual of Loader Electrical Equipment Function of KD Figure 1 15 Neutral gear locking switch Figure 1 16 Function of KD key Before driving remember to rotate up the park emergency braking button to release braking otherwise the braking system will be destroyed Refer to Figure 1 13 To ensure the driving safety please wear safety belt before driving and confirm the condition of brake is good working device is in vehicle moving status and there is no barrier or person around the vehicle Rotate the end of speed chang
29. e Manual of Loader Electrical Equipment and transistor on the semiconductor substrate to form certain function 1 4 Points for attention and marginal data in maintenance of electrical appliance I Switch of power normal configuration of more than 9 6 Series of 50 vehicles usually locate on the frame at left and back of vehicle and series of 30 vehicles usually locate in the right storage battery When open the left door of loader hoop or the cover of storage battery box seen in the Figure 1 2 the anode switch of storage battery can be seen 1 Anode switch locating on the frame at left 2 Anode switch locating in the right and back of vehicle storage battery box Figure 1 2 The position of power switch Turn off state of power switch Turn the handle of anode switch anticlockwise to the state of turning off to turn off the power of whole vehicle electric system The switch must be in state of turning off when the vehicle doesn t work Turn on state of power switch Before starting the vehicle make sure turn the handle of anode switch clockwise to the state of turning on The anode switch is different from start switch Turn off the anode switch that is turn off the electric system of whole vehicle But when turn off the start switch storage battery still connect with whole vehicle system so part of electrical components still work Never turn off the anode switch of storage battery when the engine is running otherwise the
30. e handle to go to four different gears There are first second third fourth gear four gears in all to process but there are only first second third gear three gears in all to draw back The third and fourth gear on the handle to draw back is same li Function introduction 1 Neutral gear locking function In the condition of neutral gear put the neutral gear locking switch to the position of N Shown in Figure 1 15 so the handle can t be put back or forth and locked in the position of neutral gear Put the locking switch in the position of D to release the neutral gear locking Using the switch can prevent misoperation When speed change operating handle is locked in the position of neutral gear never carry out the shifting operation of advancing or drawing back forcibly without releasing neutral gear locking otherwise the speed change operating handle will be destroyed 2 Interlock protection of neutral gear and starting function Electrical system of whole vehicle has the function of neutral gear starting interlock protection that is to say start the engine only when the speed change operating handle is in the position of neutral gear This can prevent accidents occurring when starting vehicle suddenly 2l Maintenance Manual of Loader Electrical Equipment 3 Direct reversing function The speed change operating handle hasn t the function of reversing interlock so the driver can reverse directly according to
31. e up of 5 instruments Take instrument panel of LG958 as explanation The explanation of instruments used in operating machine is as follow Understand their operation method and function completely Water thermometer of engine This indicator shows the temperature of cooling water in engine When the pointer of water thermometer is in the range of green area 60 C 100 C the temperature of water is normal If the pointer is in range of red area stop to check Please park in the safe and convenient for maintenance position Check the exhaust fan and belt of engine and also the water level of water tank Drive or work again after trouble rescinded When check the exhaust fan belt of engine and the water level of water tank please avoid burning due to high temperature and avoid clamping injury due to moving parts Oil temperature indicator of torque converter When the pointer of oil temperature indicator is in the range of green area 60 C 120 C the temperature of oil is normal When the pointer is in the red area please stop to check When the pointer is in range of red area please park in the safe and convenient for maintenance position Check the transmission and oil level of transmission Drive or work again after trouble rescinded Maintenance Manual of Loader Electrical Equipment Working hours counter This indicator shows the working time of machine The reading can regard as reference for overhaul and maintenance
32. eeereeroseoeeresreeeceseeseeeereseresroseoseresreseceeresreee 61 CHAPTER VIII ELECTRIC HORN SYSTEM sesesscsocecocoesocsosooesooossocoosoososoossoecosoecossesosossooesoseesooeoo 62 g 1 Schematic diagram seseesoscooecocososoeccocoososocoesoscsoecososocoeccsosososocsocsoecsoesoscsccoescscooscsoccesosoeccocooeosoo 62 8 2 Maintenance of common fault eeeeeeeeeeeeeeeeeeeeereeeeesrereeesereeeeeseereeseereceesserecsseereeeeseereeseseeeeens 62 CHAPTER IX STANDBY SOCKET SYSTEM Peer ere ee eee ee eee ee eee eee eee eee eee eee eee eee ee ee eee ee eee eee ee eee 63 9 1 Explanation of principle POTEET eee TEST eeereTererere Tere reeerere reer rererererereeererere seer reer errr E er eee eee 63 90 2 Maintenance Of common faulterrrrrrrrrrrrrrretttt eee eee eee e eee e enna e eee n eee e eens ee eneeeeeneeaeeeeeaees 64 Maintenance Manual of Loader Electrical Equipment CHAPTER I POINTS FOR ATTENTION AND BASIC INFORMATION IN MAINTENANCE OF LOADER ELETRICAL EQUIPMENT The content of this manual is compiled on the basis of the condition of product production and every product is in incessant improvement and protection So the manual has different vision Please repair and maintain strictly observe the maintenance and service manual which are obtained from the Lingong distributor when buying loader To repair the loader in correct method is very important to use it safely and reliably The basic maintenance methods listed in the manual are all based on the electrical ap
33. electric lock doesn t reset to ON gear Please turn off the power immediately to stop the engine if the engine does still not stop please cut off the anode of power immediately Otherwise the starting motor flameout electromagnet and storage battery will be destroyed badly 2 2 2 Fuse Fuse Fuse plays a very important role for safety protection in the circuit Substance and installation position are shown in Figure 4 to Figure 6 Notice The chip fuse used in the product should accord with the related regulation about QC T 420 Fuse used in vehicle So when replace the fuse please use the 30 Maintenance Manual of Loader Electrical Equipment required fittings by Lingong and forbid buying in the market randomly Figure 2 4 Chip fuse Figure 2 5 ZC 812 Waterproof fuse Figure 2 6 Eight way fuse box The colors of every kind of chip fuses are shown in the following table ATSI10 5A ATS7 5 7 5A ATS10 10A ATSI15 15A ATS20 20A ATS25 25A Judge the fuse whether fused in the method of visual measurement also measure with resistance 200 ohm gear of multimeter the measured value of two pins of fuse without fusing 1s about 1 ohm The installation position of fuse is shown in Figure 2 6 2 2 3 Relay 2 2 3 1 Intermediate relay JD2914 Figure 2 7 Installation position of intermediate relay Figure 2 8 Shape of intermediate relay JD2914 Some kinds of vehicles adopts JD2914 type relay and they are used as gear start li
34. ely back position boom joystick does not bounce back to neutral position after loosening The bucket turns back all the time until the bucket is in the level place and the bucket level limiting space switch begins working So the bucket tilt back keeping electromagnet loses magnetic due to power down The bucket joystick bounces to neutral position under the effect of reset spring and the bucket stop in the level position When push the bucket joystick to the extremely back position again the bucket joystick isn t catch bounce automatically after loosening because of the limiting space keeping function of bucket level limiting space switch to keep bucket tilt back keeping electromagnet in the state of power off Push the bucket joystick forward and the bucket turnover When exceed the bucket level position the bucket level limiting space switch resets and the bucket automatic level function recovers Then push the bucket joystick to extremely back position and it will keep in the extremely back position The bucket joystick in the extremely front position has not the keeping function During the bucket tilting from most bucket tilt back angle to unloading angle push the bucket joystick forward all the time bucket joystick will bounce back to neutral position after loosening The bucket will not pause when crossing the level position VII Wiping system washing system and reserve socket 1 Wiper and washer The whole vehicle equips with front and b
35. erator generates electricity normally and treatment measures errr E EEE EEE eee eee e eee e cent nese eens seen eee e ee eeae eee es 37 2 2 6 Starting Motor svete terete tee tetteeteee tent tetetene tenets tetsenenaeeenentenesenenaeeetaenenes 38 2 2 7 Storage battery vcr tent eeteeet tent eenetenetenenenereenenaeeesenenesnenennenetsentes 41 22 8 Power switch E E PUN HD w a Wee 0 4 5 4 95 06 6a NEN o pale h O s BHC E en woes 42 2 3 Example for maintenance of system common faults settee tte eeettetttttttee este teees 43 2 3 1 Maintenance of power system common faults Whole vehicle no electric 43 2 3 2 Maintenance of power system common faults Turn off electric lock but engine doesn t stop and whole vehicle still has electricity rerrrereereett teeters 44 10A electric fuse is burn down 2 3 3 Maintenance of power system common faults frequently rte tertretere terete terete teeta rene enenaeeettenaenetenestensenecneneeeeseneseenseseneensenensenenae tages 4A 2 3 4 Analysis for fault in starting whole vehicle eeeeeseseseeee ee tetee ttt tee teen eenenees 44 CHAPTER II INSTRUMENTS Y ST BIW kepers dip ip a e e E A E eA 46 3 1 Schematic diagram of instrument system 0eeeeeeeeeeeteereerterteertertertrerterttertertreeerterees 46 3 2 Explanation of main parts verter terete teeter renee ne neneenetenennetenenne renee tenant tae 46 3 2 1 Instrument panel assembly vteeetetetetetetetetererererererererererererererererererererereresesereret
36. erereresererererere rere rere rere rere rere rere rere rere rere eee 53 5 1 2 Explanation of principle POPES eSETETETeTeTeTerererererererereserere rere reresererererererererere rere rere reer rey 53 5 1 3 Maintenance of system common fault the headlight doesn t lightos 53 5 2 Circuit of work light taillight and interior trimming light rr vrrerrrrtterrr tte terres 54 5 3 Circuit of steering light POPPE TeTETETeTeTeTeTeTeTererererererereeerererererererererererere rere ee re rerere reer errr eee rere 55 5 4 Circuit of lamplet POOP er er er erererererererererer errr errr errr errr E rere rere rere rere rere rere rere 56 5 5 Circuit of brake light OEP ee eT ee ee See Seer ee reer er ere re rerere rere rere rere rere rere rere rere rere rere reer reer rere rere rere rere 57 CHAPTER VI BACKING VEHICLE ALARMING SYSTEM eee eee eer eee eee eee eee eee eee eee eee ee eee eee 59 6 1 Explanation of principle POPE eT eT eee E E E EEEE E EEE E E E RE E er eee eee 59 6 2 Analysis foymmereyantaale ele che mutter 59 CHAPTER VII WIPER AND CLEANER SYSTEM eee eer ee eer eee re eer ee eee ee eee ee eee ee eee eee eee eee eee eee eT 60 Fal Explanation of principle POPPE eT TESTES ee eTeTeTereTe Tere Tee e a a a e e e ES 60 7 2 Maintenance Of common fault eeeeeeeeeeeeeeeeereeeeeeeerereerrereeeeserereessereeeeseeeeeseereecesseeeeeseereeeeseee 61 7 2 1 Wiper motor doesn t work Corre Tet Ce eee ee ee eee 61 7 2 2 Nozzle doesn t spray Wwatep eeeeeeeeeeeereereer
37. erts electric energy of battery into mechanical energy by direct current motor and the transmission gear drives engine flywheel and then the starting of engine comes true Warning The starting motor should stop immediately after engine starts otherwise the transmission gear destroys direct current motor burns down flameout electromagnetic destroys and seriously affect the capacity and life of storage battery Connecting wire is shown in Figure 2 17 Main contact connects with cathode output cable of storage battery and connect S terminal with No 1 conductor Remember Never make a faulty connection Warning Forbid and metal conductor closing to contact 1 and contact 2 randomly Especially after vehicle vibrates and runs for a long time the fuel tube near the starting motor and other metals can not contact or friction with contacts and terminals Otherwise 38 Maintenance Manual of Loader Electrical Equipment it is possible that the whole vehicle fires Contact 2 Contact 1 j Figure 2 17 Wiring en of starting motor Notice Please check whether the connecting of contact and terminal is reliable Before checking make sure turn off the power anode Otherwise short circuit spark may be produced to destroy the wrench and terminal The explanation of principle is shown in the Figure 2 18 Flectromagnetic ol 3 Pushing and drawing coil switch Fa i cathode of batter d Contact 1 and 2 Forked plectrum D
38. gas path Refer to maintenance manual Exclude the wiring fault as follow 44 Maintenance Manual of Loader Electrical Equipment Has no electricity Circuit fault Fe gt I a ne Check according to whole electricity vehicle has no electricity Has electricity Lower than 23V Turn electric lock to start gear and check S terminal A gt No voltage Higher than 23V Abnormal Check electric lock E Replace electric lock Observe whether the flameout Normal electromagnet moves Check the signal line of start relay MOVE Don t move No voltage 24V The reason of starting motor Fault in flaneout Broken circuit itself relay or flameout of relay coil electromagnet Broken circuit or bad contact 45 Maintenance Manual of Loader Electrical Equipment CHAPTER I INSTRUMENT SYSTEM 3 1 Schematic diagram of instrument system Instrument system includes instrument panel assembly sensor and alarm pressure switch The schematic diagram is shown in Figure 3 1 Take LG958 as example other vehicle types can take it as reference Torte come rer Fugue wat Yara bk oil Fuel gauze Work hour meter taking Speedomete als barometer Smpsratms mliabI dernemekI parme pnp Instrument panel Gey fat is r ie T i H Oo S a eH E T a Lee Lee ae Left berg Eki hint oa ig i a Pa i HL 8 t 5 a Nd a A th fap Ji a ee a A a a HA A e eo oo Wi y es t a Tongue cororerter oil
39. gauge The gauge represents the surplus of fuel in the fuel tank Speedometer The gauge represents the running speed of vehicle Maintenance Manual of Loader Electrical Equipment 1 2 3 4 j 6 7 8 9 PK eda IS OFS OO 11 19 1 Oil pressure gauge of transmission 2 Braking barometer 3 Working hours counter 4 Left steering lamp 5 Indicator light 6 Speedometer 7 Right steering lamp 8 Fuel level gauge 9 Water thermometer of engine 10 Oil temperature indicator of torque converter 11 Start switch 12 Combination switch 13 Switch of watering can 14 Switch of windshield wiper 15 Cover plate 16 Switch of taillight 17 Switch of headlight 18 Switch of back headlight 19 Switch of alarm lamp Figure 1 3 Instrument panel and rocker switch assembly LG958 11 General indicating lamps on the instrument panel Preheat Oil pressure Charging Power cutting Emergency steering indicating lamp alarm lamp indice ator indicating lamp indicating lamp 7 ri e EN j 7 ia ji F j lt n amp Ao 7 yy O E S 9 2 J Parking brake Pit king aur srexsure JE ar light Computer box Fuel rough filtration indicating lamp alarm lamp indicating lamp working r indicator indicating lamp Figure 1 4 General indicating lamps on the instrument panel Preheat indicating lamp When install the function of preheat on the engine the lamp light to represent the engine is in the state of preheating The time of prehea
40. he output signal from electromagnetic valve If abnormal information combination Such as line cut off open circuit of electronic control box ground line bizarre signal appears or the power exceeds the regular restriction and open circuit occurs electronic control box shifts to neutral gear immediately to lock all signals So prevent misoperation greatly to ensure the driving safety Floating Lower B Forward x ee incline Z i e x m Boom joystick i ea Oe Bucket joystick _e Bucket joystik 1 Single handle type 2 Double handles type Figure 1 17 Operating handle of boom and bucket 23 Maintenance Manual of Loader Electrical Equipment VI Boom lifting limiting space and floating device and bucket level limiting space device The function realizes in pilot control Install the operating handle of lift arm and bucket at the right of seat Use the boom lifting limiting space and floating device and bucket level limiting space device fully can reduce effectively the labor intensity to operate the working device and increase the comfort of operation Boom lifting limiting space device When push the boom joystick to the extremely back position boom joystick is raised by boom and keep catching by electromagnet boom joystick does not bounce back to neutral position after loosening Boom rises all the time until rises to the limiting position then the boom limiting space switch begins working So the ele
41. irect current motor Figure 2 18 The inner mechanism and principle specification of starting motor Turn on the power switch the 24V terminal voltage of battery arrives to contact 1 Turn the electric lock to START gear and then the No conductor gains electricity 24V Meanwhile the current conducts through holding coil and drawing coil The electromagnetic resultant force produced by the two coils make core to move right and drive moving contact disc to move right and then contact 1 conducts with contact 2 The current conducts through storage battery contact 1 contact 2 direct current motor coil to rotate the direct current motor The iron core 39 Maintenance Manual of Loader Electrical Equipment moves right to drive forked plectrum and push transmission gear to move left and then mesh with engine flywheel The direct current motor drives flywheel to rotate and the engine begins to start During the process of starting the dozen seconds when electric lock in the START gear No 1 conductor always has electricity 24V and contact 1 conducts with contact 2 all the time and the contact voltage 1s 24V So the voltage of both ends of drawing coil is equal and there is no current conducting Now the iron core keeps in the starting state under electromagnetic force of holding coil After starting successfully the driver loosens the key of electric lock and the electric lock resets to ON gear au
42. is destroyed CHAPTER IX STANDBY SOCKET SYSTEM 9 1 Explanation of principle ZUON Standby socket CO IQA Figure 9 1 Schematic diagram of standby socket circuit Figure 9 2 Installation position of standby socket Open the electric lock and 10A electric horn fuse gains electricity 24V Connect with standby socket through No 77 and No 0 conductor When it is necessary to externally connect with power insert socket to gain electricity after connecting external connection and plug correctly Make sure that the electric power isn t more than 200W The standby socket supply a standard DC 24V power interface which can be used to externally connect with electric water heater interphone and etc The installation position is shown in Figure 9 2 63 Maintenance Manual of Loader Electrical Equipment 9 2 Maintenance of common fault The standby socket can t work normally 1 Check whether 10A electric horn fuse is fusing 2 Check whether the connector is loose and whether there is wear on the wiring harness 3 Check whether the standby socket is destroyed 64
43. kage relay back car Intermediate relay cut off the power Parking braking LAS aS Sey DI imd wating switch 0 __ Domaci with pga E i end of irag relay Connect with iF re A velle D o Sormare weh G2 ead backing lenp re of arg seth s Brake switchilett LA di a ET Caneel Wih mere patel n be T mee computer ba adeg h 4 Brake switch right Figure 5 9 Schematic diagram of braking light circuit Explanation of principle When step on braking pedal the braking pressure in the position of braking light switch can close the braking light switch contact The current conducts through 10A fuse No 57 conductor of braking light fuse switch of braking switch and No 8 conductor to two braking lights and then the two lights are lightened Don t step on braking pedal Step on braking pedal i ad e j Figure 5 10 Installation position of braking light switch Switch of braking light It is a normal open contact Act when about 1 3 bar to close the contact Maintenance of fault How to judge whether the switch of braking light is destroyed Firstly determine whether the braking pressure is normal Open the electric lock If the driving braking low pressure alarm lamp on the instruments panel 58 Maintenance Manual of Loader Electrical Equipment lights the braking pressure is normal otherwise start the vehicle until the braking low press
44. lel connection VI Voltage drop causing by the resistance of circuit There is resistance in all conductors so a certain voltage drop will be produced when the current conducting through the conductors There are two factors affecting voltage drop One is the conductor itself section area the other is the resistance lying between conductor and frame or that in the connector For example connect the electricity lock turn on the headlight and then start the diesel vehicle The headlight become darkened during starting which is leaded by voltage of storage battery drop when large current conducting through circuit Vil Three kinds of effect of current Three kinds of effect can be produced when the current conducting through circuit that is thermal effect chemical effect and magnetic effect For example the filament will heat and luminous when current conducting through bulb this is thermal effect of current when storage battery supplies electricity for electrical equipment 10 Maintenance Manual of Loader Electrical Equipment there is current conducting through electrolyte in the storage battery and there 1s bubble produced on the surface of polar plate this is called chemical effect of current when there is current conducting through the coils of instrument the pointer will swing which induced by the magnetic line around the coils this is called magnetic effect of current Vil Power The current does work when it implements ever
45. line The pushing drawing coil of flameout electromagnet is destroyed Flameout relay is destroyed Adjust the stroke again Replace the flameout electromagnet Electric lock is destroyed Replace the Open circuit flameout or bad contact electromagnet Figure 2 14 Judge the fault conditions of flameout electromagnet The method in judging whether the flameout electromagnet works normally Open the electric lock the pull rod of flameout electromagnet can t move When turn the electric lock to START gear instant the pull rod should move forward rapidly Open the oil way of fuel and loosen the key of electric lock After the electric lock automatically resets to ON gear the pull rod should not move that is keep the oil way in the state of opening Otherwise tell that the flameout electromagnet can t work normally The specific fault judgment is shown in Figure 2 14 In addition the installation of flameout electromagnet needs to assure the coaxiality and stroke of pull rod When replace the flameout electromagnet install it strictly observe the requirement 2 2 5 Generator 2 2 5 1 The principle of generator The schematic diagram of principle of generator is shown in Figure 2 15 The generator 1s made up of rotor stator transmission belt pulley fan front and back end cover and electric brush The excitation winding usually winds on the rotor and the stator uses Y shape connection
46. ltimeter 1s the terminal voltage of storage battery usually from 24V to 26V More detailed information can refer to the use and maintenance specification of storage battery 2 2 8 Power switch KOIK18 A also called anode switch installed on the more than 9 6 vehicle type The power switch controls the connection and break of storage battery anode and vehicle frame ground Close the power switch and the anode of storage battery connects with vehicle frame Open the electric lock the electrical apparatus loads of whole vehicle gain electricity Break the power switch the anode of storage battery disconnects with vehicle frame so the circuit of whole vehicle can t form loop Even if open the electric lock the whole vehicle can t gain electricity and can t start The installation position of power switch is shown in Figure 2 20 The operation of power switch O is the disconnecting position is the closing position Warning When the loader stops working please disconnect the power switch lest 42 Maintenance Manual of Loader Electrical Equipment phenomenon of the leakage of electricity and other accident occurs lf the whole vehicle line fires or the engine doesn t stall after closing electric lock or other accident occurs please turn off the power switch immediately qm gt Figure 2 20 Power switch Before connecting battery cable or fastening terminal of battery again or removing battery
47. ning When carry out the daily maintenance of storage battery please read the safety information on the nameplate of storage battery carefully Otherwise serious physical injury may be caused Notice The installation of storage battery must be fasten and reliable to avoid chipping when vehicle driving and shaking 41 Maintenance Manual of Loader Electrical Equipment Know the state of storage battery electric quantity according to change in color of electric eye also called state of charge display densimeter Green Normal Black Need to charge Light or white Battery scrap The vehicle can t start which likely caused by electric quantity of battery is not enough or the cables of battery don t connect reliably Notice Check the cable connection of battery and grounding point frequently Before checking please break the anode of power Before assembling and disassembling the battery cables please break the anode of power When assembling install the pile head of cathode firstly and then install the pile head of anode when disassembling remove the pile head of anode firstly and then remove the pile head of cathode lest the short circuit spark destroys pile head of battery and wrench The method to detect terminal voltage of storage battery Detect with DC 200V of multimeter Red pen connects with storage battery cathode output cable pile head and black pen storage battery anode pile head and then the reading of mu
48. nkage retreat alarm and lighting control respectively The installation position 1s shown in Figure 10 The relay has 85 86 87 87a 30 five terminals in all There is a coil between 85 terminal and 86 terminal and the resistance is about 330 ohm There is a normal open contact between 30 terminal and 87 terminal as well as a normal closed contact between 30 terminal and 87a terminal 31 Maintenance Manual of Loader Electrical Equipment 30 6 a8 82 6b Figure 2 9 Schematic diagram of relay The working principle of relay is shown in Figure 2 9 After the coil is energized 30 terminal connects with 87 terminal and disconnects with 87a terminal after the coil is cut off electricity 30 terminal disconnects with 87 terminal and connects with 87a terminal The method in judging whether the relay is destroyed Measure with the resistance gear of multimeter the resistance between 85 and 86 is about 330Q the resistance between 30 and 87 is infinite Connect 85 with the cathode of DC 24V power and connect 86 with anode of DC 24V power and 30 and 87 should conduct with each other Figure 2 10 Installation position of battery relay Figure 2 11 Working principle of battery relay 2 2 3 2 Battery relay The contact of this relay 1s copper plate surface contact type and the installation position is shown in Figure 2 10 There are four terminals on the contactor There is a coil between two small bolts and the resistance is a
49. ns and pumps water 2 Check whether the waterway is disconnected water pipe is disconnected or bound too compact 3 Check whether the nozzle is blocked 61 Maintenance Manual of Loader Electrical Equipment CHAPTER Vil ELECTRIC HORN SYSTEM 8 1 Schematic diagram Horn assembly Horn button Figure 8 2 The installation position of electric horn Explanation of principle Open the electric lock and 10A electric horn fuse gains electricity 24V Press down the switch of electric horn and the current conducts through 10A electric horn fuse electric horn switch of electric horn ground then the electric horn shown in Figure 8 2 buzzes continuously 8 2 Maintenance of common fault Open the electric lock and press down the switch of electric horn but the electric horn 62 Maintenance Manual of Loader Electrical Equipment doesn t sound 1 Check whether 10A electric horn fuse is fusing 2 Check whether the switch of electric horn the button switch in the middle of traversing mechanism works normally Under normal condition press down switch of electric horn and then the No 12 conductor connects with ground 3 Check whether the connector is loose and whether there is wear on the wiring harness 4 Check whether the electric horn is destroyed Connect one terminal with 24V power and connect the other terminal with ground If the electric horn doesn t sound it is determined that the electric horn
50. nt 46 3 2 2 Temperature Sensor 0eeeeeeeteettteteteteteteteteteterererererererererererertrereresereresesesestserttetnt 47 3 2 3 Braking barometer eeeetetteetetetetetettttttttrerertrertrertrtstetetetetetenetereseneseseresenereneneet 47 YIA Foe Vel senora Ea E ane nee ee teeta A 48 3 2 5 Alarm pressure switcheeeeeeetetttetttetttttttrtttrtrertrtetrtetetetetetetetenerereseseseresesererenenet 48 3 3 Example for maintenance of system common faults eeeeeeeeererreereereerterreereerteereereen 48 3 3 1 Abnormal INGIGATION OF thernriomnete ieee n n E RR 48 3 3 2 Abnormal indication of fuel level ennnen e EEEE Ea RAE aat 48 CHAPTER IV AUTOMATIC RESET SYSTEM eeeeeeesessessessesseseesseseessesseesessesseseesseesesseeseereeseese 50 4 1 Schematic diagrams strstr teeters teeete tenets reneteneenenenetneneeneneneenenseneenenaenecntgs 50 Maintenance Manual of Loader Electrical Equipment 4 2 Explanation of system function ieeeeeeeeeeeerererereereerererseeeeeseereeersereceesereecssereceesereeesereceeeseeeeee 50 4 3 Maintenance of system fault eeeeeeeeereereererreeeeeseeeeeseereeeeseeeeeeneereeenseeeeessereceesereeeeseereeeeeeeeeees 52 CHAPTER V LIGHTING SYSTEM Peer eee e eee ere rere ee rere eee ee ee eee eee eee eee eee eee eee eee eee eee eee ee eT eee eee eee eee eee eT 53 5 1 Circuit of front combination lamp POPE eT eSTT ETT eT Tre Terererererererererererererererereyererererere rere rere rer erry 53 5 1 1 Schematic diagram POPPE eTeeeTerererererererererererer
51. oltage of No 9 conductor in the backing vehicle annunciator If the voltage is normal 24V the backing vehicle annunciator 1s destroyed and needs to be replaced If there 1s no voltage generally show that the connector is loose or there 1s wear on the wiring harness Analysis of common fault Open electric lock Whatever gear to push to the backing vehicle annunciator always sounds this kind of fault is usually caused by adhesion of backing switch contact while caused by short circuit between No 9 conductor and some supply line in the very few case CHAPTER Vil WIPER AND CLEANER SYSTEM 7 1 Explanation of principle 1 The principle of cleaner Open the electric lock and 10A wiper fuse gains electricity 24V Connect with the washing switch automatic reset rocker switch the detailed information can refer to the attachment information of rocker switch The washing motor installed on the kettle gains electricity through No 37 conductor and stars to work The water in kettle is pumped to the nozzle installed under forward looking windowpane and sprayed on the windowpane Figure 7 1 Schematic diagram of wiper and water spraying kettle 60 Maintenance Manual of Loader Electrical Equipment 2 The principle of wiper The wiper motor is permanent magnet motor and uses cathode controlling method As Figure shows that the wiper motor connects with five conductors outside Among them the red conductor is supply line public
52. or E ground connect with No 0 conductor When work normally the flash relay will send out slight DA sound and the frequency is about 50 times per minute Otherwise the flash relay is determined to be destroyed 3 Switch of alarm light Switch of parking light controls four steering lights and two steering indicating lamps on the instrument panel Turn on the switch four steering lights and two steering indicating lamps will flash at the same time to warn ambient vehicle The detailed information can refer to the attachment rocker switch information The basic principle and maintenance of system fault are mostly similar to headlight circuit and don t explain here 5 4 Circuit of lamplet Schematic diagram Refer to Figure 5 6 56 Maintenance Manual of Loader Electrical Equipment Right combined light 50 mE cle 30 4o SO ane Figure 5 6 Schematic diagram of lamplet circuit The installation position of lamplet is shown in Figure 5 7 and Figure 5 8 The basic principle and maintenance of system fault are mostly similar to headlight circuit and don t explain here Figure 5 7 Combined headlight Left Figure 5 8 Left taillight 5 5 Circuit of brake light Braking circuit with electronic control transmission Schematic diagram Refer to Figure 5 9 57 Maintenance Manual of Loader Electrical Equipment Connect with computer box Infemmediate relay Intermediate start lin
53. ow voltage circuit formed in vehicle and engineering machinery all over the world is regulated to be negative ground IV The voltage in engineering machinery The nominal voltage in vehicle or engineering machinery is mostly 12V or 24V 9 Maintenance Manual of Loader Electrical Equipment which is usually distinguished like this Gasoline vehicle applies 12V electrical system but diesel vehicle applies 24V electrical system All of engineering machinery use diesel vehicle so the electrical system is 24V But very few diesel vehicles apply 12V electrical system For example Lingong export loader LG918 with KANGMINGSI engine small sized excavator LG655 with YANGMA engine and LG670 with KANGMINGSI engine As to human prove by many experiments The DC or AC is harmful to human body as long as it is more than 36V When it is less than 36V there is no harm even if human contract with charged body directly So the voltage under 36V is called safety voltage V The basic connecting method of circuit Series connection all loads are connected one by one to form a pathway Its characteristic 1s the same current is conducted through each load The total resistance of series connection is equal to the sum of every resistance Parallel connection the same terminal of all loads connects with cathode of power and the other terminal connects with anode which is called parallel connection Most circuits in vehicle and engineering machinery use the paral
54. pliance diagrams so please understand the principle diagrams deeply before repairing Make sure understand and remember the information of safety warning and points for attention before maintenance otherwise your loader will be damaged The manual has mistakes inevitably because of the limitation of editor Criticism from every user and maintenance personnel is warmly expected 1 1 Operating specification and points for attention in maintenance of electrical system When repair the loader electrical system please obey the following points strictly Otherwise small fault will become great accident to lead to greater economic loss When repairing please disconnect the power of main engine before disconnecting the connection between conductor and connector otherwise the wiring harness will be damaged and the fuse will be fused even the fire will occur due to the short circuit of conductor Identify the signal of conductor correctly Each conductor on the wiring harness corresponds to a signal with single or double figures Please distinguish between 3 and 8 6 and 9 5 and 6 0 and 8 1 and 7 and etc to avoiding taking trouble Connect the connector When connecting the connectors especially for the collect connectors please watch the letters and figures on connector carefully such as CN 1A CN2 B and etc to avoid connecting by mistake Connect the connectors Maintenance Manu
55. position of backing car the backing car alarm can sound automatically 26 Maintenance Manual of Loader Electrical Equipment CHAPTER I THE PRINCIPLE OF POWER SYSTEM 2 1 The explanation of principle Interior trim ceiling lamp __ Starting switch Intermediate relay Tos Cd reefer B lezle 6215 Lu starting linkage gt m oF 4 T 5 E HEAT ete I Z ON ope tte Smo Msema a 3 O gt Contacting with computer box La J DATIOATIOA IGATIOAT 10AT 10A 25A pon fam 0 1 gt ts on ALIA i ii gt 0 J bo 8 TOAIOA pre To charging indicator To working Fuse hour countet Power switch NY storage battery Battery amp y Starring TOA Fuse relay motor s enerator Pot E 1 tl a1 60A a Bt ta Figure 2 1 Schematic diagram of power system Explanation of principle take 958 exported vehicle as example the principle of other vehicle type is basically similar 1 After turning on the power switch anode switch the voltage of storage battery series connection of two storage batteries the nominal voltage is 24V conducts through No 56a line 60A large fuse and No 56 line to one contact of power relay then conducts through No 3 conductor connector CN1 5A electric lock fuse and No 121 conductor to the power terminal B B2 of electric lock In addition No 3 conductor supplies power for interior trimming ceiling lamp through 10A interior trimming ceiling
56. pparatus sintered loads of whole vehicle still have The electric lock is destroyed Replace electric lock electric For example when Due to the No 3 conductor of Connect fixing wiring operating the switch of power relay is loosen and then harness or conductor luminaire the lamp lightens contact with No 28 conductor again when operating the switch of windshield wiper the windshield wiper works etc 2 3 3 Maintenance of power system common faults 10A electric fuse is burn down frequently Fault Feature Fault Reason Treatment Method Turn on the electric lock The Short circuit of flameout Replace flameout 10A electric lock fuse is burn electromagnet holding coil Draw electromagnet down immediately out the connector of flameout electromagnet and then turn on electric lock If fuse isn t burn down again it can be concluded that it is the fault Short circuit of power relay Replace power relay Remove the No 3 conductor of power relay and then turn on electric lock If fuse isn t burn down again it can be concluded that it is the fault No 3 conductor short connects Bind and fasten wiring with ground due to wear or other harness again reasons 2 3 4 Analysis for fault in starting whole vehicle The fault is divided into wiring fault and mechanical fault Analysis for wiring fault is shown in Figure The mechanical fault 1s mainly the fault in oil way of fuel or
57. r out peak pulse and high frequency interference emitted by generator 36 Maintenance Manual of Loader Electrical Equipment 2 2 5 2 The connection method of Weichai generator used in LG953 L A Figure 2 16 Generator The generator is general kit diesel engine Take the generator matched in Weichai engine of domestic 50 type loader as example the working voltage is 28V the current is 55A and constant voltage regulator is set inside See the Figure 2 16 The generator has three terminals they are B generator power supply output terminal D charging indicating signal W phase output terminal can be used as timer signal and also can be used as tachometer signal Parallel connect generator with storage battery to supply electricity for electrical equipments of whole vehicle Before the machine starting the storage battery supplies electricity after the machine starting the generator supplies electricity meanwhile generator supplies electricity for storage battery Warning Forbid generator supplying electricity for electrical equipments without storage battery Warning Forbid checking whether the generator generates electricity in the method of instant short circuit of cathode and anode of generator to generate spark so as not to burn out silicon diode and affect the regulator Notice Terminal B connects with No 2a conductor terminal D connects with No 20 conductor terminal W connects with No
58. r with one small bolt and connect anode with the other small bolt and then the two big bolts should conduct with each other 33 Maintenance Manual of Loader Electrical Equipment Figure 2 13 Installation position of flameout relay 2 2 4 Flameout electromagnet only part of vehicle type As to different vehicle type the working principle of flameout electromagnet is different The current general type is power off and shut off oil type that is to say gain electricity to open oil circuit and power off to close oil circuit Flameout electromagnet connects with red white and black wires outside The coil holding coil resistance between red and black wire is about 40Q and the coil drawing coil resistance between white and black wire is about 1Q Notice when connecting the wires red 28 white 29 black 0 and Never connect reversely Otherwise the flameout electromagnet will be burn down or the lines of whole vehicle will fire 34 Maintenance Manual of Loader Electrical Equipment Flameout electromagnet can not work normally Does the pull rod act or not at the instant of turning electric lock to START gear Doesn tact easure the voltage of white Flameout Open circuit of holding when turning the electric lock to electromagnet is circuit Draw out the START gear installed incorrectly connector and measure the stroke of pull the resistance between rod is not enough red and black
59. s front combination lamp far or close light filament gains electricity 24V so the left and right headlights work in the corresponding gear at the same time Combination switch The installation position is shown in Figure 5 4 5 1 3 Maintenance of system common fault the headlight doesn t light 1 Check whether the bulb is blackening If 1s we can determine that the bulb is 53 Maintenance Manual of Loader Electrical Equipment destroyed and replace it 2 Draw out the connector and put the dimmer switch in far light gear and close light gear respectively Detect the voltage of No 49 and 50 conductor with DC voltage gear of multimeter If the voltage is 24V check whether the connector connects reliably If the connection is loose connect again If connection is reliable the inner connection of headlight is loose or bulb is destroyed If the voltage is OV please check according to the following steps 3 Check whether 10A headlight fuse is fusing 4 Check whether the connection connects reliably and wiring harness wears 5 Refer the attachment combination switch information to check the function of dimmer gear 5 2 Circuit of work light taillight and interior trimming light Taillight far and close light rocker switch Figure 5 2 Schematic diagram of taillight 54 Maintenance Manual of Loader Electrical Equipment Head lamp rocker switch Back lamp rocker switch ermunal ermunal Head lamp Figure 5
60. starting relay close and turn on the No 2 conductor and No 1 conductor Then the current conducts through No 2 conductor connector CN1 and No 1 conductor to electromagnetic switch coil of starting motor The starting motor begins working The current conducts through No 22 conductor connector CN1 and holding coil of flameout electromagnet in the same time to ground The contactors of flameout relay close and the No 2 conductor and No 29 conductor turn on and then the current conducts through No 2 conductor No 29 conductor connector CN20 and starting coil of flameout electromagnet to ground So the flameout electromagnet coil begins working and the oil way of fuel opens The starting motor drives flywheel of engine to rotate and then the engine starts After the engine starts the generator under the driving of rotating pulley begins to generate electricity the nominal voltage is 28V On the one hand the generator charges up the storage battery through 70A large fuse No 2 conductor contactors of 28 Maintenance Manual of Loader Electrical Equipment battery relay No 56 conductor 60A large fuse and cathode output cable of storage battery on the other hand the generator supplies electricity for loaders of whole vehicle from 70A fuse to shunt fuse 4 After engine starts the driver loosens the key of electric lock and the electric lock automatically resets to the ON gear No 28 and 60 conductors are cut off the electricit
61. the fittings which accord with the requirement of Lingong and never buy in the market randomly 1 2 The using method of digital multimeter The method in measuring dc voltage TANAR l Put the switch on the required measurement range of voltage The system voltage of this loader usually is 12V OR 14V so often use the DC 200v 2 Connect black pen with COM jack and connect red pen with VQ jack 3 Connect red pen with check point and connect black pen with ground then the reading is the voltage of check point I The method in measuring resistance Figure 1 1 VC98 series of digital multimeter Connect black pen with COM jack and connect red pen with VQ jack and then put the switch on the required measurement range of resistance Connect the pens on the both ends of resistor to be measured and then the reading is the resistance value II The method in measuring diode Put the measurement range on the position of and then connect black pen with COM jack and connect red pen with VQ jack Then connect red pen with cathode of diode and connect black pen with anode of diode and the reading should be small Maintenance Manual of Loader Electrical Equipment The more detailed using method safety requirements and points for attention can refer to the service manual of multimeter 1 3 The basic circuit knowledge of engineering machinery I The definition of circuit The pathw
62. ting is not too long Oil pressure alarm lamp After turning on the starting switch the lamp is lightened immediately after starting engine it goes out in a moment Otherwise the Maintenance Manual of Loader Electrical Equipment lubricating oil level is too low or fault occurs in lubricating system and flameout immediately to check the engine Charging indicator The indicator lights when turn on the starting switch when charging the engine the indicator goes out if the lamp lights when engine is running check the charging circuit Power cutting indicating lamp Lamp on represents power is cut and lamp off represents power is not cut When step on the left brake pedal or put down the park emergency braking button the power is cut and lamp turns on when step on the right brake pedal the power is not cut and lamp turns off 11 Emergency steering indicating lamp The lamp turns on when install the function of emergency steering and vehicle carry out steering emergently while the emergency steering pump is running Parking brake indicating lamp The lamp turns on when put down switch of parking brake or braking air pressure is low the lamp turns off when braking air pressure 1s normal or turn the switch of parking brake to release braking Braking air pressure alarm lamp The lamp is lightened to alarm when braking air pressure is lower than 0 4MPa Far light indicating lamp The lamp turns on when front headlight
63. tomatically and then the No 1 conductor is cut off electricity immediately In a moment the current conducts through contact 1 contact 2 pushing drawing coil S terminal holding coil ground So the current direction of holding coil is contrary to that of pushing drawing coil and both producing magnetic fields are opposites The force and electromagnetic force of iron core cancel out so the iron core resets to initial position under spring force Now contact 1 disconnects with contact 2 and current doesn t conduct through drawing coil and holding coil and also the transmission gear resets to initial position The starting motor stops working The judgment to normal faults of starting motor l Fault phenomenon Close the anode switch then the starting motor runs automatically Judgment Caused by contacts sintered moving contact disc cements with contact 1 and 2 Treatment method Grind contacts and moving contact disc again or replace electromagnetic switch or replace starting motor 2 Fault phenomenon When starting the starting motor has no any response Judgment and treatment method Check the voltage of No 1 conductor at the S terminal of starting motor while turn electric lock to START gear If the reading is zero check the electric lock starting relay storage battery etc If the voltage is normal turn on the electric lock again to measure whether the contact 1 has electricity 40 Maintenan
64. turns on Computer box working indicating lamp Reserving device Fuel rough filtration indicating lamp Lamp on represents fuel rough filter is blocked please clean or replace it The position of horn switch is shown in the Figure 1 5 Figure 1 5 Horn switch The horn switch locates in the center of steering wheel and it is normal open 17 Maintenance Manual of Loader Electrical Equipment contact IV Lamp lamp switch Figure 1 7 Rear lamp Figure 1 8 Interior trimming ceiling lamp Figure 1 9 Taillight The lamps of whole machine are divided into front combination lamp one for both sides rear lamp one for both sides interior trimming ceiling lamp front and rear light one for both sides in front of cab selection fitting at the back of cab taillight one for both sides and rotating alarm lamp installed on the cab electively In which the front combination lamp includes front light front steering lamp and clearance lamp Steering lamp is controlled by the steering switch on instrument panel 1 Switch of alarm lamp After closing the switch of alarm lamp front and rear steering lamps four lamps in all turn on simultaneously When stop emergently in the condition of emergency the lamp plays a role of warning 18 Maintenance Manual of Loader Electrical Equipment CRT RE Cee ee gee RA Hd t2 ts ee PE Ett j tti HEAT EPE Figure 1 10 Wane switch assembly 2 Switch of rear light Switch of
65. ure alarm lamp doesn t light If normal draw out the conductor of braking light switch and then detect the two pins of switch with resistance 200Q gear of multimeter If the testing result is inconsistent with the following table the pressure switch has already been destroyed and needs to be replaced CHAPTER VI BACKING VEHICLE ALARMING SYSTEM 6 1 Explanation of principle Right taillight Backing buzzer Figure 6 1 Schematic diagram of backing vehicle alarming system The explanation of principle Open the electric lock and there is electricity in the 10A backing vehicle alarm fuse Then push to reverse gear and connect the backing switch so the No 9 conductor gains electricity and backing buzzer sends out the buzzing sound Meanwhile the backing lights on left and right taillight are lightened 6 2 Analysis of common fault Open the electric lock and push to reverse gear but the backing vehicle annunciator doesn t sound 1 Check whether the 10A backing vehicle annunciator fuse is fusing 2 Check whether the connector and conductor connect firmly and reliably Looseness of connector or wear of wiring harness usually leads to broken in the middle of No 9 conductor 59 Maintenance Manual of Loader Electrical Equipment 3 Check whether the backing switch is destroyed If it is good please push to reverse gear Connect the two conductors of backing switch 4 If there is no problem in the above test please check the v
66. y and contacts of starting relay are disconnected and No 1 conductor is cut off the electricity and then the starting motor stops meanwhile disconnect the contacts of starting relay and the No 29 conductor and drawing coil of flameout electromagnet is cut off electricity But the holding coil still works and the oil way of fuel continues opening and then the engine continues running 5 Turn off the electric lock turn the electric lock to OFF gear The No 28 conductor and holding coil of flameout electromagnet are cut off the electricity and then the engine stops and the generator doesn t generate electricity any more meanwhile coil of battery relay is cut off the electricity contactors turn off No 2 conductor is cut off the electricity so the loaders of whole vehicle is cut off electricity the function 1s only limited in the vehicle with flameout electromagnet 6 Turn off the power switch and then the whole vehicle is cut off electricity 2 2 The introduction of main components 2 2 1 Electric lock ia SIAR pet teteto Figure 2 2 JK412A type electric lock Figure 2 3 08081 10000 type electric lock 1 JK412A type electric lock export vehicle type See in Figure 2 2 a The electric lock has B B2 M S G1 and G2 five pins in all The G1 and G2 pin are not used generally b B B2 pin is power pin and connects with No 121 conductor M pin is firing pin and connects with No 28 conductor S pin is starting pin
67. y electric effect The electric work supplied or consumed in one second is called electric power and the signal is P The power is proportional to the product of voltage and current that is P U I IX Resistor Resister is a component that consumes electric energy and turns electric energy into heat energy completely For example the component to adjust wind speed in the air conditioning system is a resister X Capacitor The unit of capacitor is F Farad The role of capacitor is storage the direct power energy proportional to capacitance proportional to charging voltage The characteristic of capacitor DC can t conduct through capacitor but AC can And the higher is frequency of AC the more easily to conduct XI Coil self inductance The unit of self inductance is H Henry Wind the conductor in the same direction continuously to form coil But AC is difficult to conduct and the higher is frequency of AC the more difficultly to conduct For example every relay electromagnet and electromagnetic instrument using in engineering machinery are all the examples of coil application XI Diode Diode is a semiconductor device which only can conduct current in one direction The main application in engineering machinery is silicon rectifier diode and zener diode on the generator and freewheeling diode on the relay X Integrated circuit Integrated circuit is a circuit block which assembles resistant capacitor diode 1 Maintenanc
68. y electromagnet coil can catch the boom Joystick now the driver can loosen his hand and the boom joystick can t spring back to neutral position The boom always lifts until it closes to the proximity switch At the moment of closing the proximity switch cuts the output signal and red light goes out So the magnetic force of electromagnetic coil disappears and boom joystick springs back to 50 Maintenance Manual of Loader Electrical Equipment neutral position automatically under spring force and then the boom doesn t lift any more Boom floating device The device doesn t include proximity switch There only is a boom floating coil located on the pilot control valve After open the electric lock the coil always gains electricity When the driver push joystick to foremost the magnetic circuit closes and the magnetic force generating by electromagnet coil can catch the boom joystick now the driver can loosen his hand and the boom joystick can t spring back to neutral position The big and small cavities of boom tank conduct with tube by pilot valve through controlling distributing valve The pressure of big and small oil cavities both are zero and the pressure difference is also zero If driver pushes joystick to floating position during shoveling operation the bucket fluctuates with the fluctuation of ground If diver pushes boom joystick to floating position to operate the boom to drop boom can drop with the fastest speed under

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