Service Manual - Doosan Infracore
Contents
1. 1 Alternator Does Not Charge 2 Alternator Charge Rate Is Low Or Not Regular 3 Alternator Charges Too Much 4 Alternator Is Noisy Troubleshooting Problems Problem 1 Alternator Does Not Charge Probable Cause 1 Loose Drive Belt For Alternator Adjust the alternator drive belt 2 Loose Alternator Drive Pulley Check the key groove in the pulley for wear If the groove is worn install a new pulley Tighten the pulley nut to the correct torque See Specifications 3 Charging Or Ground Return Circuit Or Battery Connections Are Defective Inspect all cables and connections Clean and tighten all connections Replace defective parts 4 Rotor Field Winding Or Regulator Is Defective Install a new rotor or regulator assembly Bosch Alternators Problem 2 Alternator Charge Rate Is Low Or Not Regular Probable Cause 1 Loose Drive Belt For Alternator Adjust the alternator drive belt 2 Loose Alternator Drive Pulley Check the key groove in the pulley for wear If the groove is worn install a new pulley Tighten the pulley nut to the correct torque See Specifications 3 Charging Or Ground Return Circuit Or Battery Connections Defective Inspect all cables and connections Clean and tighten all connections Replace defective parts 4 Regulator Is Defective Install a new regulator assembly 5 Rectifier Is Defective Install a new rectifier 6 Brushes Are Worn Or Dirty Install new brushes Probl2. or shorted and the rectifier must be replaced Bosch Alternators Negative Diode Check 8 Negative diode 1 Put the multimeter on the diode scale Connect the meter leads between each negative diode 8 and the surface of the rectifier that is not painted The negative diodes are silver 2 Note the meter reading and reverse the meter leads 3 One reading should be OL and the other 4 to 9 volts If both readings are OL or low 0 to 1 volts the diode is open or shorted and the rectifier must be replaced Exciter Diode Check IDASO19C Exciter Diode Check 7 Positive diode 9 Exciter diodes connection 1 Put the multimeter on the diode scale Connect the meter leads between exciter diodes connection 9 and each positive diode 7 three of them 2 Note the meter reading and reverse the meter leads 3 One reading should be OL and the other 4 to 9 volts If both readings are OL or low 0 to 1 volts the exciter diode is open or shorted and the rectifier must be replaced Testing and Adjusting Brush Tests Brush Continuity Test IDASO20C Brush Continuity Test 10 Positive brush 11 Terminal 1 Put the multimeter on the 200 ohm resistance scale Touch the meter leads between positive brush 10 and terminal 11 2 The meter reading should be 1 to 3 ohms If the resistance is not correct the positive brush is open or sh
3. 7 Brushes Stator 3 consists of a stator core and coils As the rotor turns its varying magnetic field causes the stator coil to produce three phase alternating current AC Pe Es IDAS006C Rotor 4 Rotor 6 Slip ring Rotor 4 consists of a core coils and slip ring 6 The rotor provides the magnetic field between the rotor field winding and the stator Slip ring 6 provides the surfaces for brush contact Bosch Alternators There are two brushes 7 They contact the two rotating slip rings on the rotor Current flows to the rotor coil through the brushes and slip rings There is one positive and one negative brush The brush material is copper graphite IDAS008C Rectifier 5 Rectifier 10 Positive diodes 11 Negative diodes Rectifier 5 contains three positive diodes 10 and three negative diodes 11 They form the full wave rectifier which is connected to the stator Rectifier 5 changes or rectifies three phase AC to DC The rectifier also provides excitation current through three exciter diodes not shown Systems Operation IDAS009C Regulator 8 Regulator Regulator 8 controls alternator output It is mounted on the alternator rear frame assembly IDASO10C Capacitor 12 Capacitor Capacitor 12 smooths alternator DC voltage The capacitor is mounted on the back of the alternator Bosch Alter
4. DASO34B K1 Alternator 1 Regulator 4 Pulley 5 Fan 6 Screws 8 Rotor 9 Bearing cover 11 Front bearing 12 Rear bearing 13 Slip ring 18 Rectifier 19 Stator Assemble Alternator IDAS033C 3 Install slip ring 13 on the rotor Connect and solder the rotor leads to the slip ring Install rear bearing 12 IDAS031C aa 1 Connect and solder stator 19 leads to the positive diodes of rectifier 18 4 IDASO34C 4 Install bearing cover 9 front bearing 11 and spacer 10 on the rotor Bosch Alternators 24 Disassembly and Assembly IDAS035C 5 Install rotor 8 and the four screws into the front frame 7 Install the key fan 5 pulley 4 washer and pulley nut IDASO36C N ES 1DAS038C _ t a 6 Assemble front frame and rotor assembly 22 into rear frame and stator assembly 21 Make sure the wave washer is in the rear frame bearing bore Align the front and rear frame marks made at disassembly for correct assembly Install the four screws Bosch Alternators 25 8 Install the capacitor and connect capacitor lead 2 to the back of the alternator 9 Install regulator 1 End By a install alternator Disassembly and Assembly
5. Introduction dada 7 Testing And Adjusting Alternator Component Tests 17 Brush Tests nt telnet 21 Capacitor Test 18 Rectifier Tests ooooocccconncccconoccccconnccccnonancnnnnnos 20 Regulator Test 17 Rotor Field Winding Tests 19 Stator Tests 19 Alternator Output Test nenn 16 Bench Test 17 Machine Test ne 16 TrOUDIESNOOTING nenn ennnn nennen nennen 15 Troubleshooting Problem List 15 Troubleshooting Problems 15 Disassembly And Assembly A ee 22 Assemble Altemaior 24 Disassemble Alternator 22 Index Specifications Alternator Bosch Alternator Coverage Chart DAEWOO Part Model Number Number Voltage Amperage 8C5535 K1 12 32 IDASO20B Alternator End View IDASO19B Alternator Sectional View IDAS021B Alternator Enclosed End View Bosch Alternators 5 Specifications ALTERNATOR SPECIFICATIONS ALTERNATOR TIGHTENING SPECIFICATIONS DAEWOO P NO 8C5535 DAEWOO P NO 8C5535 Model Number K1 Pulley Nut 1 Torque 35 10 Nem 25 7 lb ft Voltage Being Tey Thru Bolts 2 Torque 4 1 to 5 5 Nem Polarity Neg Grd 36 to 49 Ib in Rotation CW Terminal Torques 3 6 0 8 Nem Test Speed 5000 rpm B Seg Iben Rated Output Cold 29A B 2757 gt 25 0 em Output voltage 14 0 0 5V D 20 0 2 2 lb in Rotor Field Wind
6. SB2008E01 Service Manual Bosch K1 Series Alternators Important Safety Information Most accidents involving product operation maintenance and repair are caused by failure to observe basic safety rules or precautions An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs A person must be alert to potential hazards This person should also have the necessary train ing skills and tools to perform these functions properly Read and understand all safety precautions and warnings before operating or performing lubrication maintenance and repair on this product Basic safety precautions are listed in the Safety section of the Service or Technical Manual Additional safety precautions are listed in the Safety section of the owner operation maintenance publication Specific safety warnings for all these publications are provided in the description of operations where hazards exist WARNING labels have also been put on the product to provide instructions and to identify specific hazards If these hazard warnings are not heeded bodily injury or death could occur to you or other persons Warnings in this publication and on the product labels are identified by the following symbol A WARNING Improper operation lubrication maintenance or repair of this product can be dangerous and could result in injury or death Do not operate or perform any lubrication maintenance or repair on t
7. TOR D D DIODES LIMITING RESISTOR 1 IGNITION OR KEY START SWITCH POSITIVE DIODES BATTERY ROTOR EXCITATION WINDING IDAS028B Pre excitation Circuit Typical The existing residual magnetic field of the rotor generates this breakdown voltage only at high speed Systems Operation Therefore the alternator has to be pre excited during start up This is done by taking current from the battery through the ignition or key start switch limiting resistor and on some alternators a diode assembly When the ignition or key start switch is turned on pre excitation current flows from the positive terminal of the battery through the ignition or key start switch limiting resistor and diode assembly if equipped to the D terminal of the regulator The current flows through the regulator to the excitation winding where it is grounded It is then returned to the negative side of the battery As current flows through the excitation winding it produces a magnetic field strong enough to start self excitation of the alternator Regulator Operation The transistor regulator is the Bosch type EE It is used on all K1 alternators except the K1 enclosed alternator The EE will be used in describing the construction and operating of the regulator The most important part of the regulator is formed by two integrated assemblies 1 TWZ which includes transistor T1 resistor R4 and uni directional b
8. blies for proper assembly Remove four screws 6 one has a nut on it on the back of the alternator 5 Separate the front frame and rotor assembly from the rear frame and stator assembly Watch for the wave washer at the back of the rear frame assembly to fall out 2 IDASO25C x 6 Remove four screws 7 and rotor 8 from the front frame Disassembly and Assembly IDASO26C IDASO29C Ea 7 Remove spacer 10 and front bearing 11 with a suitable puller Remove bearing cover 9 from the rotor IDAS027C 10 Remove three screws 17 Remove the stator and rectifier assembly from the rear frame Remove the remaining insulators from the terminal studs 8 Remove rear bearing 12 with a suitable puller Unsolder both rotor winding leads from slip ring 13 Remove slip ring 13 with a suitable puller 9 Remove terminal nuts 14 15 and 16 Remove all of the washers and insulators Bosch Alternators 11 Unsolder the three stator leads and separate rectifier 18 from stator 19 Disassembly and Assembly IDAS032C _ ES 2 Position the insulators on the rectifier terminal studs Position rectifier 18 and stator 19 into the rear frame and install the three screws Install the terminal insulators washers and nuts Position wave washer 20 into the bearing bore of the rear frame I
9. e power diode to winding W negative at this instant of time completing its circuit at the neutral point Bosch Alternators Pre excitation CiRcuit When in operation at high speed the alternator is self excited Excitation current for the magnetic field is obtained from the main current However when initially starting the alternator depends on residual magnetism When the current of an electromagnet is disconnected the magnetic field does not disappear completely The iron core remains slightly magnetic This is called residual magnetism There is enough residual magnetism in the core to induce a small voltage in the stator windings This small voltage causes a weak current to flow through the closed circuit of the excitation winding This current produces a weak magnetic field of its own This is added to the residual magnetism of the core and slightly boosts the intensity of the exciter field A boosted exciter field results in a higher voltage The effect is cumulative and the process repeats itself until the desired voltage corresponding to the alternator speed is reached The exciter circuit in the alternator contains three positive diodes three negative diodes and three exciter diodes Alternator self excitation cannot start until the pre excitation circuit produces the breakdown voltage required by two of the diodes one negative diode and one positive diode per phase connected in series EXCITER DIODES D REGULA
10. ed below the set value and diode ZD has returned to the non conducting state the excitation winding is switched on again This cycle in which the excitation winding is alternately supplied with voltage or is short circuited through diode D3 is repeated in periodic sequence The on off ratio depends on the rotational speed of the alternator and the load current requirements of the system Bosch Alternators 14 Capacitor C smooths the DC voltage Resistor R7 insures the fast precise switching of transistor T2 and T3 Resistor R7 also reduces switching losses Temperature compensation diodes 4 adjust system voltage according to ambient temperature The charg ing voltage must be higher in cold weather than in hot weather Systems Operation Testing And Adjusting Troubleshooting Troubleshooting can be difficult Following is a list of possible problems To make a repair to a problem make reference to the probable cause This list of problems and probable causes will only give an indication of where a possible problem can be and what repairs are needed Sometimes more or other repair work is needed beyond the recommendations in the list Remember that a problem is not normally caused by one part but by the relation of one part with other parts This list cannot give all possible problems and probable causes The serviceman must find the problem and its source then make the necessary repairs Troubleshooting Problem List
11. em 3 Alternator Charges Too Much Probable Cause 1 Alternator Or Regulator Has Loose Connections Tighten all connections to the alternator or regulator 2 Regulator Is Defective Install a new regulator assembly Problem 4 Alternator Is Noisy Probable Cause 1 Drive Belt For Alternator ls Worn Or Defective Install a new drive belt for the alternator 2 Loose Alternator Drive Pulley Check the key groove in the pulley for wear If the groove is worn install a new pulley Tighten the pulley nut to the correct torque See Specifications Wi Drive Belt And Drive Pulley For Alternator Are Not In Alignment Make an adjustment to put the drive belt and drive pulley in correct alignment 4 Alternator Bearings Are Worn Install new bearings in the alternator Testing and Adjusting Alternator Output Test FAULT CONDITIONS AND POSSIBLE CAUSES Current At Voltage After About Start Up 10 Min Is Below Spec Voltage After About Voltage After About 10 Min Is In Spec 10 Min Is Above Spec Repair alternator defective Ee regulator open stator phase Below Specification deu rectifier H Turn on all accessories If voltage drops below spec repair alternator open rectifier and or stator phase Reached Specification Repair alternator and then tapered off defective regulator Alternator and battery in spec Repair alternator Turn on all accessories to verify shorted regulator Volta
12. ge must stay in spec Exceeds Specification Check battery f and stays high Do alternator test again if necessary Alternator in spec Repair alternator E shorted regulator ate Also check battery for possible damage NOTE The proper drive pulley is required for the correct alternator output Tools Needed 5 The alternator output should stabilize within Digital Multimeter or Equivalent 1 approximately 10 minutes at full throttle possible AC DC Clamp On Ammeter 1 Machine Test 1 Put the multimeter positive lead on the B terminal of the alternator Put the negative lead on the negative terminal or frame of the alternator Put the clamp on ammeter around the positive output wire of the alternator 2 Turn off all electrical accessories With the fuel off crank the engine for 30 seconds Wait two minutes to let the starting motor cool If the system appears to operate at the specifications crank the engine again for 30 seconds NOTE Cranking the engine for 30 seconds partially discharges the batteries in order to do a charging test If batteries are already low in charge skip this step Jump start engine or charge batteries as required 3 Start the engine and run at full throttle NOTE Full throttle approximates the required drive pulley speed of 5000 rpm 4 Immediately check output current When operating correctly this initial charging current is equal
13. ges are zero the current would flow as shown in illustration Phase Relationships 150 Equal currents flow from windings U and V to the respective positive diodes They return to the neutral point through W winding negative diode and winding W Note that not all the diodes belonging to the various phases are used at the instant of time examined in this example This remains true of all the other instants of time which could be examined Individual phase currents change in magnitude and polarity while the output current to the battery or electrical accessories remains uniform Systems Operation Excitation Circuit The exciting current for generation of the magnetic field is taken from the stator winding It is rectified by three exciter diodes and the three negative power diodes The exciting current follows the path shown in the illustration REGULATOR EXCITER DF DIODES DIODES y EXCITATION WINDINGS 0 OS S lt c nou zo EG IDAS027B Phase Relationships Excitation circuit with phase angle of phase U 120 Current flows from the output of winding U positive at this instant of time through its corresponding exciter diode and the alternator D terminal to the regulator D terminal When the regulator is turned on current then flows to the regulator DF terminal to the excitation winding by the way of terminal DF ofthe alternator Current then flows to the alternator terminal D and the negativ
14. his product until you have read and understood the operation lubrication maintenance and repair information Operations that may cause product damage are identified by NOTICE labels on the product and in this publica tion DAEWOO cannot anticipate every possible circumstance that might involve a potential hazard The warnings in this publication and on the product are therefore not all inclusive If a tool procedure work method or operating technique not specifically recommended by DAEWOO is used you must satisfy yourself that it is safe for you and others You should also ensure that the product will not be damaged or made unsafe by the operation lubri cation maintenance or repair procedures you choose The information specifications and illustrations in this publication are on the basis of information available at the time it was written The specifications torques pressures measurements adjustments illustrations and other items can change at any time These changes can affect the service given to the product Obtain the complete and most current information before starting any job DAEWOO dealers have the most current information avail able Bosch Alternators Index Specifications E Ee EE 5 Systems Operation Alatorre a Es 7 Alternator Operation ooooocccocccnonccccononannnnnannnnos 7 Alternator Components nen 7 Alternator Operation Schematic 9 Regulator Operation 13
15. ing 3 4 to 3 7 2 25 0 25 Nem Resistance D 20 0 2 2 Ib in Field Current 2 25 0 25 Nem 28 0V or 14 0 3 8 to 4 1A DF 20 0 2 2 Ibin Stator Winding Resistance 14to 15 Ww 2 Turn On Speed Max Slip Rings 3 Maximum Runout TIR 0 03 mm 001 in 27 00 mm Minimum Diameter 1 06 in Brush 4 Length 17 00 mm New 67 in Brush 4 Length 11 5 mm Minimum 45 in Brush Spring Force 2 0 to 3 8 N 45 to 86 Ib Bosch Alternators Specifications Systems Operation Alternator Introduction The K1 Series Bosch Alternator has three phase full wave rectified output It is the brush type See the Bosch Alternator Coverage Chart in Specifications for the list of alternators covered in this module Alternator Operation IDAS004C Bosch Alternator The alternator is an electrical and mechanical component driven by belt rotation from the engine It is used to charge the storage battery during engine operation The alternator is cooled by a fan that is part of the alternator The fan pulls air through the back of the alternator The air exits the front of the alternator cooling it in the process The alternator converts mechanical and magnetic energy to alternating current AC and voltage This process is done by rotating a direct current DC electromagnetic field rotor inside a three phase stator assembly The alternating current and voltage generated by the stator are changed to d
16. irect current DC by a three phase full wave rectifier system The rectifier system has six silicon rectifier diodes DC current flows to the alternator output terminal The rectifier also has three exciter diodes They rectify the current needed to start the charging process A solid state regulator is installed on the back of the alternator Two brushes conduct current through two slip rings to the rotor field A capacitor installed on some alternators smooths alternator DC voltage Bosch Alternators These alternators are self exciting at high speed That means they have residual magnetism in the rotor The excitation circuit cannot start the charging process until the pre excitation circuit produces the required breakdown voltage The alternator is connected to the battery through the ignition or key start switch This connection supplies the necessary current to the pre excitation circuit This current is available every time the ignition switch is turned on Alternator Components DCL ES 5333555 IDAS022B Alternator Components 1 Fan 2 Front frame assembly 3 Stator 4 Rotor 5 Rectifier 6 Slip ring 7 Brushes 8 Regulator 9 Rear frame assembly The major components of the alternator are stator 3 rotor 4 rectifier 5 regulator assembly 8 brushes 7 and a capacitor if equipped Systems Operation IDAS005C IDAS007C Stator Brushes 3 Stator
17. meter on the 20M resistance scale Connect one multimeter lead to capacitor lead 2 Touch the other lead to capacitor mounting screw 1 4 There should be a very low resistance for a short period of time Then resistance should stabilize above 100 000 ohms meter reading 0 10 or greater 5 If the reading is not correct replace the capacitor Testing and Adjusting Rotor Field Winding Tests 2 Both readings should be 100 000 ohms or greater a oeh Ae meter reading 0 10 or greater Rotor Field Winding Continuity Test 3 If the meter reading is low the rotor is grounded and must be replaced Stator Tests Stator Winding Continuity Test IDAS013C Rotor Field Winding Continuity Test 3 Rotor 4 Slip ring _ Put the multimeter on the 200 ohm resistance scale Touch the meter leads to each slip ring 4 IDASO15C on rotor 3 as shown Stator Winding Continuity Test 2 The resistance values should be as follows 5 Stator 6 Stator leads See specifications for the K1 12V alternators 8C5535 Alternators 3 4 to 3 7 ohms Tools Needed 3 If the resistance is not correct the rotor is open or Ohmmeter capable of measuring 1 shorted and must be replaced less than 0 1 ohms Rotor Field Winding Ground Test Put the multimeter on the 200 ohm resistance wech scale Connect the meter leads between each pair of stato
18. nators Alternator Operation Schematics The electrical schematics that follow indicate terminals and basic circuitry for the K1 series alternators EXCITER DIODES O D CAPACITOR EXCITATION WINDING IDAS023B K1 Series Alternator Schematic 12V Systems Operation EXCITER DIODES D B STATOR WINDINGS IDAS024B K1 Series Fully Enclosed Alternator Schematic 12V Bosch Alternators 10 Systems Operation Charging Circuit Current for battery charging and for the electrical accessories is taken from the B terminal of the alternator The flow of current for battery charging and electrical accessories at an instant of time 120 phase angle is shown in illustration Phase Relationships 120 STATOR WINDINGS w U POS V 0 W NEG 120 IDAS025B Phase Relationships Charging circuit with phase angle of phase U 120 Voltage at the output of winding U is positive while it is negative at W and zero at V no voltage The current path is as follows Output from winding U through positive diode U alternator terminal B battery ground alternator terminal D negative diode W output of winding W to the neutral point Bosch Alternators 11 W V O BATTERY STATOR WINDINGS Uv w U POS V POS W NEG 150 IDAS026B Phase Relationships Charging circuit with phase angle of phase U 150 If another time instant is chosen 150 phase angle where none of the volta
19. nses output voltage If the voltage is low the regulator allows field current flow and the voltage builds When output voltage exceeds the upper limit field current is turned off The output voltage of a properly functioning alternator and regulator is IRE 14 0 0 5V The voltage should not vary more than approximately 0 3V during this process This test measures voltage when the regulator turns field current on and off and determines if there is an open or short in the diode trio exciter diodes field coil or regulator Testing and Adjusting mua Connect variable power source VPS positive lead to the alternator B and D terminals as shown Connect VPS negative lead to the alternator B terminal or frame ground 2 Adjust the voltage of the VPS until ammeter A first indicates current draw Measure voltage V and write this measurement down as turn on voltage When correctly operating the turn on voltage is 12V System unnnsnssnnennennnnnennnoneaneen 14 0 0 5V 3 Ammeter A reads field current When correctly operating the field current is See Specifications for the K1 12V alternators 805535 Alternators 3 8 to 4 1A at 14 0V NOTE Divide the voltage that first indicates field current by rotor field winding resistance as shown in specifications This will give the correct field current that should be seen on ammeter A 4 If ammeter A indication is zero amps the rectifie
20. orted and the brushes must be replaced Brush Ground Test IDASO21C Brush Ground Test 11 Terminal 12 Negative brush 1 Put the multimeter on the 20M resistance scale Touch the meter leads between negative brush 12 and terminal 11 2 The meter reading should be 100 000 ohms or greater meter reading 0 10 or greater H the resistance is low the brush is grounded and the brushes must be replaced Bosch Alternators 21 Brush Length Check IDASO33B Brush Length Check 10 Brush X Brush length 1 Measure the length of brushes 10 on the longest side Brush length X should be as follows New length K1 12V alternators 17 0 mm 67 in Minimum length K1 12V alternators 11 5 mm 45 in 2 If the brushes are worn near or below the minimum length replace them Testing and Adjustinga Disassembly and Assembly Alternator NOTE The disassembly and assembly that follows is of a K1 12V alternator The other alternators are similar Disassemble Alternator Start By a remove alternator IDAS024C e 1 Remove the two screws and regulator 1 2 Disconnect capacitor lead 2 from the back of the alternator Remove the screw and capacitor 3 IDAS023C 3 Remove the pulley nut washer pulley 4 fan 5 and the key from the rotor shaft Bosch Alternators 4 Mark the front and rear frame assem
21. r or field coil or regulator are open If ammeter A indication is too high see Step 2 the field coil may be shorted The regulator is also bad if the turn on voltage is not 12M System cin 14 0 0 5V 5 If the measurements in Steps 3 and 4 are correct go to Step 6 If they are not correct the alternator and or regulator are bad gt Adjust VPS to the turn on voltage as measured in Step 2 Slowly increase the voltage until ammeter A indicates zero amps Write this voltage down as turn off voltage 7 The difference between the turn off and turn on voltages must be no more than 0 3V A larger value indicates a regulator malfunction Also ammeter A should drop sharply to zero amps If not the regulator is faulty Gei If the alternator and regulator meet all test requirements and there is still a problem do the additional component tests that follow Bosch Alternators 18 Capacitor Test IDAS0110 Discharging Capacitor 1 Capacitor mounting screw 2 Capacitor lead 1 Disconnect capacitor lead 2 from its terminal on the back of the alternator Remove the plastic housing from lead 2 that surrounds the clip 2 Touch lead 2 to the capacitor mounting screw 1 This discharges the capacitor NOTE Each time this test is done the capacitor must be discharged Ki IDAS012C we Capacitor Test 1 Capacitor mounting screw 2 Capacitor lead 3 Put the multi
22. r leads 6 of stator 5 for a total of three readings N The resistance values should be as follows See Specifications for the K1 12V alternators 805535 Alternators ou 14 to 15 ohms Wi If the resistance is not correct the stator is open or shorted and must be replaced IDASO14C Rotor Field Winding Ground Test 3 Rotor 4 Slip ring 1 Put the multimeter on the 20M resistance scale Touch the meter leads between each slip ring 4 and the rotor shaft Bosch Alternators 19 Testing and Adjusting Stator Winding Ground Test Negative Diode Check IDAsotgc Stator Winding Ground Test 5 Stator 6 Stator leads 1 Put the multimeter on the 20M resistance scale Connect one meter lead to each stator lead 6 and touch the other meter lead to the stator frame 2 The resistance value should be 100 000 ohms or greater meter reading 0 10 or greater 3 If the meter reading is low the stator is grounded and must be replaced Rectifier Tests Positive Diode Check IDASO17C Positive Diode Check 7 Positive diode 1 Put the multimeter on the diode scale Connect the meter leads between each positive diode 7 and the B stud The positive diodes are black 2 Note the meter reading and reverse the meter leads 3 One reading should be OL and the other 4 to 9 volts If both readings are OL or low 0 to 1 volts the diode is open
23. reakdown diode ZD This is the control stage 2 TWT which includes transistor T2 resistor R5 and transistor T3 This is the output stage The following circuit diagrams show what happens in the regulator when the excitation current is switched ON and OFF The actual value of the alternator voltage between terminals D and D is detected by a voltage divider which is formed by resistors R1 R2 and R3 Connected in parallel with R3 is a unidirectional breakdown diode ZD This diode determines the system charging voltage at the regulator A partial voltage is constantly applied to this diode This voltage is proportional to the alternator voltage Bosch Alternators Regulator Switched ON IDAS029B Regulator Circuit Diagram Switched On 1 Output stage 2 Control stage 3 Voltage divider 4 Temperature compensation diodes C Capacitor As long as the actual voltage is below the set alternator voltage the breakdown voltage of diode ZD is not yet reached No current flows through the branch of the circuit containing diode ZD No current flows to the base of transistor T1 Transistor T1 is in a non conducting state With transistor T1 in the non conducting state control current can flow from the exciter diodes and terminal D through resistor R6 to the base of transistor T2 This current switches transistor T2 on Transistor T2 now makes the connection between terminal DF and the base of
24. the procedure that follows IDAS031B Alternator 1 Jumper wire 2 D terminal 3 DF terminal 1 Repeat Steps 1 3 of Machine Test Ground the field by connecting jumper wire 1 from D terminal 2 to DF terminal 3 as shown This calls for full alternator output 2 If output is now within 10 amps of rated output the regulator is bad and must be replaced 3 If output is not within 10 amps of rated output the alternator must be disassembled for component testing See Alternator Component Tests Bench Test Put the alternator on an alternator test bench The maximum current output and regulated voltage should be the same as shown in the machine test Bosch Alternators 17 Alternator Component Tests Tools Needed Digital Multimeter or Equivalent 1 Regulator Test TEST EQUIPMENT CHART Quantity Symbol Description 1 VPS 0to 40V 6A Variable Power Supply 2 V A Digital Multimeter Or Equivalent VPS _ FRAME GROUND IF ALTERNATOR DOES NOT HAVE B TERMINAL IDAS032B Test circuit For Regulator Test K1 Shown This test can be performed to determine an alternator or regulator malfunction This test does not cover all of the failure possibilities but verifies a few common problems See the Test Equipment Chart for the equipment needed for this test Alternator output voltage is regulated by controlling field coil current The regulator se
25. to or greater than the full output current shown below A ran 29A Bosch Alternators longer depending upon battery size condition and alternator rating When operating correctly the alternator output voltage is EA 14 0 0 5V If the alternator is NOT performing within specifications see the Fault Condition and Possible Causes chart 6 The charging current during this period should taper off the less than approximately 10 amps depending again upon battery and alternator capacities If the charging current does NOT decrease as specified see the Fault Conditions and Possible Causes chart 7 The K1 alternators are self excited at high speeds For this reason they are turned on by the battery through the ignition or key start switch to start the charging process at low speed They are turned on any time the ignition or key start switch is either in the ON or START position 8 On lift trucks check the alternator light to make sure its working properly Also if a machine is jump started because the battery is too low the alternator may not have any output This is because the battery may be too low to send current to the alternator The alternator needs current to start the charging process 16 Testing and Adjusting Regulator Test If the alternator does not have the correct output the field can be grounded on the 8C5535 alternators This can be done on the machine to determine if the regulator is bad Do
26. transistor T3 Therefore if transistor T2 conducts so does transistor T3 The excitation current now flows through transistor T3 Current also flows through the excitation winding and increases during on time causing the alternator voltage to rise At the same time there is a voltage rise across the voltage divider and diode ZD 13 Systems Operation Regulator Switched OFF IDAS030B Regulator Circuit Diagram Switched OFF 1 Output stage 2 Control stage 3 Voltage divider 4 Temperature compensation diodes C Capacitor When the system voltage finally exceeds the regulator set value diode ZD starts to conduct when the breakdown voltage is reached Current now flows from D through resistors R1 R2 and diode ZD to the base of transistor T1 which now conducts Now the voltage across the base of transistor T2 drops and the base current stops flowing Transistors T2 and T3 are turned off The excitation circuit is now interrupted The alternator excitation is suppressed and the output voltage drops again The interruption of the excitation current now generates a turn off voltage spike as a result of the induction in the excitation winding stored magnetic energy which could destroy transistors T2 and T3 To prevent this the decaying excitation current is discharged through free wheeling diode D3 which is connected in parallel with the excitation winding As soon as the alternator voltage has dropp
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