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1. Call your dealer or distributor AFTER POWER RETURNS TRANSFER SWITCH DOES NOT RETURN TO NORMAL POSITION 1 The retransfer time delay period may not have expired Checkthe Retransfer Timing lamp on the Power Sentry Open the cabinet door and check the Motor Disconnect switch position For automatic op eration it should in the Auto position AC power within the cabinet and the rear side of the cabinet door pre sents a shock hazard that can cause severe personal Injury or death Use extreme cau tion to avold touching electrical contacts whenever the cabinet door Is open Manually initiate retransfer by tuming the Test Normal Retransfer switch to Retransfer Stop the generator set with the Start Stop switch When the generator set stops the transfer switch will transfer load to the Normal powersourceif power is acceptable Call your dealer or distributor If the switch still does not retransfer manually return the switch to the Normal position See Operation Call your dealer or distributor 4 3 GENERATOR SET CONTINUES TO RUN AFTER RETRANSFER OF LOAD TO NORMAL POWER The stop time delay function may not have expired Check the Stop Timing lamp on the Power Sentry Stop the generator set with its Start Stop switch and call your dealer or distributor BATTERY CHARGER FA LSTO CHARGE IF EQUIPPED Check the battery charg r f se S Replace if nec essary with fuses of the correct rating Fus2. 2 Move the M tor Disconnect switch to the Off position 3 1 3 Transfer from the Normal to the Emer gency power source A Pull the upper manual operator handle down B Push the loweramanual operator handle down Retransfer fromthe Emergency to the Nor mal power source C Pullthe tower manual operator handle up D Push the upper manual operator handle UP 4 Before moving the Motor Disconnect switch back tothe Auto position remember the trans fer Switch will transfer load to the active power Source If both power sources are available it will transfer the load to the Normal source Automatic transfer switch op eratlon results In rapid movement of the manual operator handles and presents a hazard of severe personal Injury Keep hands clear of handles when swltching back to automatic operation 5 Move the Motor Disconnect switch to the Auto position 6 Close the cabinet door GENERATOR SET EXERCISE Run the generator for at least 30 minutes once each week with at least 50 percent load if possi ble If you do not have an optional exerciser use the Test Normal Retransfer switch as described below to test the generator set each week The optional exerciser has preselected exercise periods and exercises the generator set automati cally with or without load depending on the position of the Exercise With Without Load switch If the Normal power source has an interruption while the generator set
3. 7 when the indicator is under the de sired day number 5 To enter the complete start stop program press the Pr button 8 If all programprequire ments have been satisfied the display returns to the time of day Ifthe program requirements are not met the display of the section that needs correction flashes on and off To enter more programs repeat the two 5 step pro cedures A maximum of ten programs can be en tered The same ten programm can be repeated each day The word Full appears imthe display when the memory is full If the VO button 2 is pressed and no program is to be entered press the Ch button 6 andthen the Pr button 8 to get out of the program mode To check the programs 1 Press the Ch button 6 An I 12 and an O T5 are displayed Press the Ch button 6 again The start and stop information for the first program is dis played Continued pressing of the Ch button 6 causes the display to sequence through all of the programs in memory If ten programs have been entered the word Full appears after the tenth program display Press the Pr button 8 to return to the time of day display To change edit a program 1 Press the Ch button 6 until the program you want to change appears in the display window Press the I O button 2 to select start or stop time Press the h 3 m 4 or 1 7 5 and Q 7 but tons to
4. ometer with the desired marking on the faceplate Figure 2 5 FIGURE 2 5 SIGNAL MODULE If a time delay Sidesired make sure thatthe Delay No Delay switch is in the Delay position Load Shed Option The optional Load Shed function is used to discon nect the load from an available Emergency source in order to reduce the power consumed from that source When the load shed function is initiated the switch is moved to the neutral position The load shed function is initiated by a customer supplied signal When load shedding is in effect a return of Normal utility power will cause immediate retransfer to the Normal power source If the load shed signal is removed before Normal power returns the switch will transfer back to the Emergency side Remote Test Transfer The transfer switch may be wired with a remote test switch Closure of a set of contacts across the re mote test transfer inputs causes the transfer switch to sense a simulated utility power failure and send a start run signal to the generator set The load is transferred to the generator set when generator set power becomes available Referto the Installation and Service manuals Float Battery Charger Option A float charge battery charger Figure 226 regu lates its charge voltage to continuously charge without damage to the battery As th battery ap proaches full charge the charging current auto matically tapers to zero amperes Onto steady s
5. 2 If your transfer switch has two wire starting check the generator set The operation selec tor switch on the generator set control panel should be set at Remote Check for fault indi cators on the generator set control 3 Start the generator set using its start stop ton trols If it does not crank check the startingbat teries If it cranks but does not start check the fuel supply If the problem persists Call your dealer or distributor Ignition of explosive battery gases can cause sev r amp personal Injury Do not smoke or cause any spark or flame while servicing batterles Ignitlon_of fuel can cause se vere personal Injury or death by fire or ex ploslon Do not permit any flame cigarette spark pllot light arcing equipment or other possible source of Ignition near the fuel system 4 1 GENERATOR SET STARTS DURING NORMAL POWER SERVICE 1 Two wire starting only for water cooled gen erator sets The operation selector switch on the generator set control panel should be set at Remote AC power within the cabinet and the rear side of the cabinet door pre sents a shock hazard that can cause severe personal Injury or death Use extreme cau tion to avold touching electrical contacts whenever the cabinet door is open Three wlre starting only for air cooled gen erator sets The Auto Stop Handcrank switch on the 3 wire start module should be set at Auto Check the Test Normal Retransfer switch to
6. 2 2 The Power Sentry includes voltage sensing circuits time delay circuits and control relays There are also several adjustment potentiometers and indicator lamps on the Power Sentry The ad justments must be performed only by qualified service personnel Accidental actuation of the linear motor could cause severe personal Injury Dis able the motor as described below before making any adjustments Place the Motor Disconnect Switch Figure 2 2 In the Off position when making adjustments Return the switch to the Auto position after ad justments are completed AC power within the cabinet and the rear side of the cabinet door presents a shock hazard that can cause severe personal Injury or death Use extreme cautlon to avold touching electrical contacts when the cabinet door Is open Power Sentry Time Delays Start Time Delay This delay is adjustable from 0 to 15 or optionally from O to 90 seconds This brief time delay prevents generator set starting during power interruptions of short duration Timing starts the moment of Normal utility powerinterruption If the duration of interruption exceeds the delay time the control system signals the generator set to start To set this time delay align the slot on the potenti ometer with the desired marking onthe Power Sen try cover Stop Time Delay This delay is adjustable from O to 10 minutes It begins timing when the load is retransferred to the Normal power source
7. At the end of the delay the stop signal is sent to the gen erator set This time delay allows the generator set to cool down at no load before stopping To set this time delay align the slot on the potenti ometer with the desired marking onthe Power Sen try cover Transfer Time Delay This delay begins when generator voltage and frequency reach the settings of the control After the delay the transfer switch transfers the load to the Emergency power sourtes This brief time delay allows the generator set to Sta bilize before the load is applied It has an Adj st able range of O to 120 seconds To set this time delay align the sloton the potenti ometer with the desired marking onthe Power Sen try cover Retransfer Time Delay This delay begins the mo ment Normal line voltagetandifrequency return Af ter the delay the transfer switch can retransfer the load to the Normal Soufce The delay allows the Normal source to stabilize before retransfer It has an adjustable range of Oto 30 minutes To set this time delay align the slot on the potenti ometer with the desired marking onthe Power Sen try cover Undervoltage Sensing Twowoltage sensors one for the Normal side and oneWfor the Emergency side monitor source volt ages for an undervoltage condition and generat signals which are sentto the time delay modules for example an under voltage condition is sensed on the Normal source the voltage sensor mod
8. change the hour minute or day Press the Pr button 8 to enter the edited pro gram and return to the time of day display To erase clear a program 1 Press the Ch button 6 until the program to be erased is displayed Press the C button 10 with a ball point pen to clear the program Press the Pr button 8 to return to the time of day display Phase Sequence Balance Monitor Option The optional phase sequence balance monitor Figure 2 9 is connected to and senses A B and C phases of utility power If there is an over or undervoltage a phase reversal a loss of one phase or an unbalanced voltage condition a nor mally energized relay drops out closing a set of contacts When these contacts close the genera tor set start transfer of load sequence is initiated Five LEDs indicate normal operation or fault condi tions The Relay Energized LED is lit during normal operation Three potentiometers permit setting the percent of voltage unbalance the normal system voltage and the relay dropout time delay The relay dropout delay applles only to over under voltage and voltage unbalance In the event that a phase reversal or loss of one phase Is sensed relay dropout occurs within 100 milliseconds maximum There Is NO relay dropout delay when a phase rever sal or loss of phase Is sensed e Overvoltage dropout occurs at normal voltage 10 42 e Undervoltage dropout occurs at normal vol
9. closes the contacts that transfer the load between Normal and Emergency power The transfer switch is me chanically interlocked to prevent simultaneous closing to both power sources The main parts of the transfer switch discussed here are the contact assemblies linear actuator Motor Disconnect switch and auxiliary contacts Contact Assemblies The automatic transfer switch has either three or four poles Three pole transfer switches are pro vided with a neutral bar The contact assemblies make and break themeurremt flow When closed to either the Normakor the Emergency power source the contacts are mechanically held A mechanical interlock prevents them from closing to both power sources at the same time LinearActuator The linear actuator is a linear induction motor that moves the contact assemblies between the Normal poewen source and the Emergency power source Linear actuator operation is initiated automatically with automatic transfer switches Manual operation of the transfer switch is also possible Refer to Manual Operation in the Operation section Motor Disconnect Switch The Motor Disconnect toggle switch on the acces sory control panel enables and disables the linear actuator Place the switch in the Auto position to enable the linear actuator Place the switch in the Off position to disable the linear actuator Auxiliary Contacts Auxiliary contacts are provided on the Normal and Emergency sides of the t
10. is exercising without load the auto matic transfer switch will transfer the load to the generator set GENERATOR SET START TEST AC power within the cabinet and the rear side of the cabinet door presents a shock hazard that can cause severe personal Injury or death Use extreme caution to avold touching electrical contacts whenever the cabinet door Is open 1 Place the Test With Without Load selector switch on the Power Sentry control in the Without Load position The Test With Without Load selector switch must be In the Without Load position 2 Close the cabinet door AC power within the cabinet and the rear side of the cabinet door pre sents a shock hazard that can cause severe personal Injury or death Close the cabinet door 3 Move the Test Normal Retransfer switch to Test The generator set should start and run 4 At the end of the test period move the Test Normal Retransfer switch to the Normal posi tion The generator will stop 5 In anticipation of scheduled or automatic gen erator set exercise check that the With With out Load selector switches are in the desired positions Refer to Generator Set Exercise 6 Close and lock the cabinet door WITH LOAD STANDBY SYSTEM TEST AC power within the c binet nd the rear side of the cabinet door presents a shock hazard that can cause severe personal Injury or death Use extreme caution to avoid touching electrical contacts whenever the cabine
11. loose hardware Tighten as indicated in step 4 4 PERFORM ROUTINE MAINTENANCE a Tighten buswork control wiring power cables and system hardware as necessary Hardware torque values are given in section 4 of the Service manual 962 0512 Retorque all cable lug connections Lug torque requirements are listed in section 1 of the Service manual b Service or replace the batteries 5 CONNECT AC POWER AND CHECK OPERATION a Connect the set starting battery negative lead last Connect the normal AC power source enable the backup power source If applicable connect power to the battery charger b Verify proper operation of the battery charger c Test system operation as described in this section Close and lock the cabinet door 3 3 4 Troubleshooting The following procedures describe preliminary troubleshooting checks If the trouble persists call your dealer or distributor 1 INDICATES EXERCISE PERIOD POWER OUTAGE OCCURS BUT GENERATOR SET DOES NOT START AC power within the cabinet and the rear side of the cabinet door presents a shock hazard that can cause severe personal Injury or death Use extreme caution to avoid touching electrical contacts whenever the cabinet door Is open 1 If your transfer switch has the 3 Wire Start os module the Auto Stop Handcrank switch on the 3 Wire Start module should be set to Auto FIGURE 4 1 EXERCISER CLOCK Check for overcrank condition See Operation Section
12. make sure it is in the Normal position Check the exerciser clock to see if it is in an ex ercise period When the exerciser clock is in an exercise period a 1 appears in the upper right hand corner of the display window Fig ure 4 1 You can view the display by looking through the transparent clock cover Check that the red slide switch is in the center posi tion It the exercise perlod occurs at an unexpected time or for an excessive duration refer to the eXs erciser clock programming procedure or call your dealer or distributor Momentary voltage dips might cause voltage sensors to initiate generator set Starting Ifthe problem persists call your dealer Oradistribu tor GENERATOR SET DOES NOT EXERCISE IF EQUIPPED WITH EXERCISER 1 Two wire starting only for water cooled gen erator sets The operation Selector switch on the generator setcontrol panel should be set at Remote AC power within the cabinet and the rear side of the cabinet door pre sents a shock hazard that can cause severe personal Injury or death Use extreme cau tion to _avold touching electrical contacts whenever the cabinet door Is open 2 Three wire starting only for air cooled ger erator sets The Auto Stop Handcrank switch on the 3 Wire Start module should be set at Auto Check the exerciser to see if it is in an exercise period When the exerciser clock is in an exer cise period a 1 appears in the upper righ
13. represent Sunday Press the Pr button 8 to enter the time To set the exercise start time 1 Slide the output selector switch 16 to the cen ter position The output selector switch has three positions The Off position overrides the program and causes an exercise stop The position overrides the program and causes an exercise start The center position selects pro gram control Press the VO button 2 An 12 appears in the upper display window The I is a symbol for start time Press the h button 3 to set the start hour 4 Press the m button 4 to set the start minute Press the 1 7 button 5 to advancerth amp indica tor bar 13 from 1 to 7 and back to 1 For each day to be selected for exercise press the Q button 7 when the indicator is Over the de sired day number 1 represents Sunday To set the exercise stopffime 1 Ww Press the I O button12 A O 15 appears in the lower left displaywindow The O is a sym bol for stop4imes Press thefh button 3 to set the stop hour Press the m button 4 to set the stop minute Press the 1 7 button 5 to advance the indica tor bar 14 from 1 to 7 and back to 1 For each start time selected in step 5 above there mustbe a corresponding stop time A program can Start on day 2 pass through midnight and stop on day 3 for example but there must be a stop time for every start time Press the Q button
14. set or Stop Auto Handcrank switch on the automatic transfer switch whichever ap plies to Stop 2 Disconnect the starting battefies of the gen erator set remove the ground lead first 3 Remove AC powento the automatic transfer switch If the instructions require otherwise use extreme caution due to the danger of shock hazard Place rubber insulative mats on dry wood platforms over metal or Concrete floors when working on any electricalequipment Do not wear damp clothir g particularly wet Shoes or allow skin surfaces to be dampiwhen handling any electrical equipment Jewelry is a good conductor of electricity and sho ldibe removed when working on the electrical equipment Do notbwork on this equipment when mentally or physically fatigued or after consuming alcohol or any drug that makes the operation of equipment unsafe OT3 UG 3 1 Introduction OPERATOR S MANUAL This operator s manual provides information nec essary for operation of an OT Ill transfer switch TRANSFER SWITCH APPLICATION Transfer switches are an essential part of a build ing s standby or emergency power system The Normal power source commonly the utility line is backed up by an Emergency power source often an electric generating set A transfer switch sup plies the electrical load with power from one of these two power sources The load is connected to the common of the trans fer switch Figure 1 1 Under normal cond
15. start stop functions of generator sets Water cooled generator sets have two wire start controls and the air cooled sets have three wire start con trols CABINET The standard cabinet Figure 2 1 meets the re quirements for a UL Type 1 cabinet This type is designated as a general purpose indoor cabinet Indicator Lamps There are four indicator lamps on the cabinet door The Normal Available and Emergency Available lamps are lit whenever theifCorresponding power sources utility or generator set are producing power These two lamps can be lit simultaneously The Normal Connected lamp is lit when the auto matic transfer Switch is in the normal position The Emergency Connected lamp is lit when the automatic transfer switch is in the emergency posi tion NORMAL CONNECTED LAMP NORMAL AVAILABLE LAMP Onen Trensiar Switch PHASE SELECTOR SWITCH FOR OPTIONAL METERS OPTIONAL AUTO MANUAL SWITCH EMERGENCY CONNECTED LAMP EMERGENCY AVAILABLE LAMP OPTIONAL AC VOLTMETER OPTIONAL AC AMMETER OPTIONAL FREQUENCY METER IT TEST NORMAL RETRANSFER SWITCH M169448 FIGURE 2 1 CABINET WITH OPTIONS Test Normal Retransfer Switch This switch has three positions Inthe Normal posi tion the transfer switch is set for automatic opera tion Moving the switch to Test sends a start signal to the generator set After the transfer time delay the generator set will assume the load pro
16. O O Operator s Manual OT III Transfer Switch 40 to 1000 Amperes Utility to Generator Set_ Printed U S A 962 0113 11 92 Table of Contents SECTION TITLE PAGE 1 INTRODUCTION oia add a id 1 1 Operators Manual LL 1 1 Transfer Switch Application 1 1 Automatic Transfer Switches 1 1 Model Identification 1 2 How to Obtain Service eC kennen 1 2 2 DESCRIPTION ie eins we 2 1 G binet 22 artis IO A te 2 1 Transfer Switch LL asia 2 2 Electronic Control System MM 2 3 3 OPERATION Li 3 1 Automatic Operation A R eee ee eee 3 1 Manual Operation SET 3 1 Generator Set Exercise Ra 3 1 Generator Set Start Test RL cc ce ce eee nee 3 2 With Load Standby System Test LL 3 2 OvercranKiReset 3 2 Preventive Maintenance mm SB 3 3 4 TROUBLESHOOTING 0 4 1 Power Outage OccursabutiGenerator Set Does Not Start 4 1 Generator Set Starts During Normal Power Service ooo o o 4 2 Generator Set Does Not Exercise If Equipped With Exerciser 4 2 After a Power Failure Generator Set Starts but Does Not Assume Load 4 2 After Power Returns Transfer Switch Does Not Return to Normal Position 4 3 Generator SefGontinues to Run After Retransfer of Load to Normal Power 4 3 Battery Charger Fails to Charge If Equipped 4 3 Battery LNes Wa
17. ame while servicing batterles TABLE 3 1 ANNUAL PREVENTIVE MAINTENANCE 1 DISCONNECT ALL SOURCES OF AC POWER Disconnect both AC power sources from the transfenswiteh before continuing Turn the generator set operation selector switch to Stop The selector switch is located on the generator set control panel If there Is an external battery charger disc nnect It from Its AC power source Then disconnect the set starting battery negative lead first 2 CLEAN a Thoroughly dust and vacuum all controls ameters switching mechanism components interior buswork and connecting lugs b Close the cabinet door and wash exterior surfaces with a damp sponge mild detergent and water Do not allow water to enter the cabinet especially at meters lamps and switches 3 INSPECT a Check buswork and supp6ftingshardware for carbon tracking cracks corrosion or any other types of deterioration If replacement is necessary call your dealer or distributor b Check stationary and movable contacts If contact replacement is necessary the procedures are described in sectien 4 of the Service manual 962 0512 c Check system hardware for loose connections Tighten as indicated in step 4 d Check all control wifing and power cables especially wiring between or near hinged door for signs of wear ordeterioration e Check all controlwiring and power cables for loose connections Tighten as indicated in step 4 f Check the cabinet interior for
18. e In this position the load is not con nected to either Normal or Emergency power source This feature allows residual voltage from inductive loads to decay to an acceptable level before trans feris completed The length of timethatthe transfer Program switch is in the midposition can be adjusted from O amp Transition amp to 7 5 seconds or O to 60 seconds depending on the timer option The proper adjustment is a func tion of the load FIGURE 2 4 PROGRAMTRANSITION MODULE To set the time delay align the slot on the potenti ometer with the desired marking on the faceplate Figure 2 4 If a time delay is desired make sure that the Delay No Delay switch is in the Delay position Signal Module Option The main function of the optional Signal Module is to delay transfer or retransfer for a preset tim while operating a signal contactto give warning that a transfer or retransfer is about to occur This op Ss Signal Module tion is typically used in elevator applications 16 This module also provides four other sets ofform signal contacts The Signal Module has one adjustableitimer The Elevator Signal delay controls the timing of two events It delays transfer retransfer and energizes the Elevator Transfer Signal relay during the delay Timing period Delay Seconds This time delay is adjustable overa range of 0 to 50 seconds To set the time delay align the slot on the potenti
19. e am pere ratings are shown en the charger faceplate Ignition of explosive battery gases can cause severe personal Injury Do not smoke or cause any spark or flame while servic Ing batteries If the fuse s OK call your dealer or distributor BATTERY LOSES WATER The battery charger float voltage could be too high if equipped with battery charger Call your dealer or distributor BATTERY LOSES CHARGE Battery charger float voltage could be too low if equipped with battery charger Call your dealer or distributor E ASA A A NA RIN EA ARIES NETA AAO II OEY IO RA ATROCES ur E AAA A A Se PD gt a 2 a ige le sD tain tai are en ra Rear en x 612 574 8087 n is a registered trademark of Onan Corporation
20. itions the load is supplied with power from the Normal source as illustrated If the Normal power source is interrupted the load is transferred to the Emer gency power source When Normal power returns the load is retransferred to the Normal powef source The transfer and retransfer of the load are the two most basic functions of a transfer Switch AUTOMATIC TRANSFER SWITCHES Automatic transfer switches capable ofraut matic operation without operator involvement perform the following basic functions 1 Sense the interruption of the Normal power source 2 Send a start signal to the generator set Emer gency power source 3 Transfer the load to the Emergency power source 4 Sense the retum of the Normal power source 5 Retransfer the load to the Normal power sources 6 Send a stop signal to the generator set 1 1 NORMAL EMERGENCY FIGURE 1 1 LOAD TRANSFER SWITCH TYPICAL FUNCTION MODEL IDENTIFICATION Identify your model by referring to the Model and Specification number as shown on the nameplate Electrical characteristics are shown on the lower portion of the nameplate which is located on the cabinet door Ifitis necessary to contact a dealer or distributor re garding the transfer switch always give the com plete Model Specification and Serial number This information is necessary to properly identify your unit among the many types manufactured HOW TO OBTAIN SERVICE When the
21. ransfer switch They are actuated by operation of the transfer switch during transfer and retransfer The Normal side auxiliary contact switch is actuated when the transfer switch is inthe Normal position The Emergency side aux iliary contact switch is actuated when the transfer switch is in the Emergency position The auxiliary contacts have current ratings of 10 amperes at 250 VAC The contacts are wired to terminal block TB1 OPTIONAL PROGRAMMED TRANSITION OPTIONAL SIGNAL INDICATOR LAMPS OPTIONAL METERS OPTIONAL 3 WIRE START SWITCHES ACCESSORY CONTROL PANEL DISCONNECT SWITCH TEST amp EXERCISE WITH WITHOUT LOAD SWITCHES POWER SENTRY CONTROL AUTOMATIC TRANSFER SWITCH BATTERY CHARGER FIGURE 2 2 INTERIOR COMPONENTS ELECTRONIC CONTROL SYSTEM This section describes the standard and optional components ofthevelectronic control system Improper calibration or adjustment of electronic Control modules can cause death severe personal Injury and equipment or prop erty damage Calibration and adjustment of these components must be performed by tech nically qualified personnel only Alealibration and adjustment procedures are de sCribed in the Installation manual which was shipped with the transfer switch and in the Service manual which is available through your distribu tor 2 3 The most important component of the electronic control system is the Power Sentry control Figure
22. rred to the emergency power source A push button on the alarm module provides a means to silence the horn The Alarm lamp indicates that the transfer switch iS inthe Emergency Connected position If the hornis silenced the Horn Silenced lamp will also light Both lamps will stay lit until the transfer switch moves from the Emergency Connected position to the disconnected neutral or Normal Connected position Exerciser Clock Option The exerciser clock initiates generator set start run cycles at programmable inervalsand for program mable durations It is aW dayss24 hour clock that can store and execute up to ten start stop programs exercise cycles Programming the exerciser clock requires setting the time of day and entering the exercise start and stop times Refer to the acircled numbers in Figure 2 8 when reading the following instructions 2 8 Q FIGURE 2 7 ALARM MODULE FIGURE 2 8 EXERCISER CLOCK To set the time of day pa 6 If you are performing installation and setup press the R button 9 with the tip of a ball point pen to reset all memory Do not press the R button if you are only changing the time of day Press the clock button 1 Pressthe h button 3 to setthe hourofthe day The clock uses 24 hour military time Press the m button 4 to set the minutes ofthe hour Press the 1 7 button 5 to advance the indica tor baroverthe desired day number Use the 1 to
23. rting The starting circuitis a basic supervisory function of the electronic control Water cooled generatorsets use a two wire start control Although the logic is more involved the two wire starting circuit can be thought of as a single pole single throw switch A closed switch signals the generator set to start An open switch signals the electric generator set to stop Three Wire Starting Option The optional three wire starting control available on 40 to 125 ampere switches only enables the transfer switch to start and stop a three wire start generator set Three wire starting logic is similar to a single pole double throw switch A common is closed to one side to send a start signal and to the opposite side to send a stop signal In addition to start and stop functions the control has an over crank relay a preheat relay two Timing lamps a Lockout Lamp a Reset Switch and a Auto Stop Handcrank Switch Figure 2 3 The 3 Wire Start module may be equipped with a preheat timer On Off switch Overcrank occurs when the generator set does not start within the adjustable time limit 0 to 120 sec onds In order to protect the starter motor over crank relay contacts open the starting circuit and light the Lockout lamp After a starting problem is corrected pressing the Overcrank Reset switch re sets the circuit Refer to the Operation Section A set of overcrank alarm contacts are also pro vided The contacts can be u
24. sed to energize an ex temal overcrank alarm If used the preheat timer delays the start signal O to 60 seconds while a preheat output is energized The Preheat Timing lamp is on during this delay To set the timers align the slots onthe potentiome ters with the desired markings on_the faceplate Figure 2 3 The Auto Handcrank Stop switchahas three posi tions that function as follows Auto Allows the generator set to start and assume the loadiif a power outage oc curs This is the normal operating position Stop Shuts down the generator set and prevents it from starting Use this position when servicing the gen erator set Prevents the automatic transfer switch from starting the generator set but allows starting and stopping at the set Use this position for generator set maintenance Handcrank Connections for the optional 3 Wire Start module are made at TB3 2 5 amp 3 Wire Start Auto Handcrank Stop 10 Timing Seconds o Preheat 60 Timing Delay Seconds o 120 Lockout Over crank Overcrank Reaet FIGURE 2 3 3 WIRE START MODULE Programmed Transition Option Timing amp The optional Program Transition module Figure 2 4 is used to introduce a pause during transition Programmed transition allows the transfer switch to Delay assume a mid transition position for an adjustable Seconds 8 i o 60 interval of tim
25. t age 10 12 e Dropout time delay range is 2 to 20 seconds e Percent voltage unbalance range is 2 to 6 en 240 and 480 volt units e Percent voltage unbalance range is 2 to 8 on 380 volt units 2 10 APhase BPhase C Phase TO TB2 7 amp 8 307 2601c FIGURE 2 9 PHASE SEQUENCE BALANCE MONITOR 3 Operation AUTOMATIC OPERATION Place control switches in the positions given below e TestNormal Retranster switch Normal position e Motor Disconnect switch Auto position e Operation selector switch engine control Remote position Two wire start for water cooled generator sets only e Stop Auto Handcrank switch Auto position Three wire start for air cooled generator sets only The generator set must also be set for automatic operation MANUAL OPERATION The transfer switch has operator handles for manuz ally transferring the load Use the following proce dure AC power within the cabindtandithe rear side of the cabinet door presents a Shock hazard that can cause severe personal Injury or death Use extreme cautlon to avold touching electrical contacts whenever th cabinet door Is open If possible remove all AC power to the transfer switch before manually operating the switch If it is necessary to perfofm manual operation with AC power connected follow the Safety Related Work Practices listed In NFPA 70E 1 Open the cabinetidoor of the automatic trans fer switch
26. t hand corner of the display window Figure 4 1 You can view the display by looking through the transparentycloek cover Check that the red slide switch is in the center posi tion Start the generator set using its start stop con trols If it does not crank check the starting batteries If it cranks but does not start check the fuel supply Ifthe problem persists call your dealer or distributor Ignition of explosive battery gases can cause severe personal Injury Do nothsmoke or cause any spark or flame whllesservicing batteries Ignition of fuel can cause se vere personal Injury or death by fire or ex Plosion Do not permit any flame cigarette spark pilot light arcing equipment or other possible source of Ignition near the fuel system AFTER A POWER FAILURE GENERATOR SET STARTS BUT DOES NOT ASSUME LOAD Check the output voltage of the emergency power source by observing the voltmeter on the generator set or the optional voltmeter on the automatic transfer switch Open the cabinet door and check to see if the MotorDisconnectswitchisinthe Auto position AC power within the cabinet and the rear side of the cabinet door pre sents a shock hazard that can cause severe personal Injury or death Use extreme cau tion to avold touching electrical contacts whenever the cabinet door Is open Check the Source 2 Available lamp on the Power Sentry Manually transfer the switch see Operation
27. t door is open 1 Place the Test With Without Load selector switch on the Rower Sentry control in the With Load position 3 2 The Test With Without Load selector switch must be in the With Load position In order to test with load 2 Close the cabinet door AC power within the cabinet and the rear side of the cabinet door pre sents a shock hazard that can cause severe personal Injury or death Close the cabinet door 3 Move the TestNorm l Retr nsfer switch to Test The generator set should start and as sume the load after the transfer time delay 4 At the end of the test period move the Test Normal Retransfer switch to the Normal posi tion if youwantito retransfer load back to the Normal powensource after the retransfer time delay To bypass the retransfer time delay and cause immediate load retransfer move the Test NormalRetransfer switch to Retransfer and release the switch will return to Normal The generator will stop after the stop time de lay 5 In anticipation of scheduled or automatic gen erator set exercise check that the With With out Load selector switches are in the desired positions Refer to Generator Set Exercise 6 Close and lock the cabinet door OVERCRANK RESET 3 Wire Start Only An overcrank condition exists when the generator set fails to start within the overcrank time limit When this condition occurs the Lockout lamp on the 3 Wire Start module will light To resetthe a
28. tate load on the battery There are two chargers available One battery charger is rated for 10 amperes at 12 or 24 VDC The other battery charger iswated for 2 amperes at 12 or 24 VDC The 2 amperefbatteryacharger has an ammeter to indicate charging Current and a fuse to protect the battery charger amp ircuit The 10 ampere battery charger has three fuses two on the AG input and one on the DC output three fault display LEDs and an ammeter for indi catiomef charging current 2 7 10 AMP CHARGER FIGURE 2 6 BATTERY CHARGER On the 10 ampere charger three sets of form C alarm contacts corresponding to the three fault LEDs are also available Using an optional alarm contact harness these contacts can be wired by the installer to activate other audible or visual alarms Under normal operating conditions the Low Bat and AC Fail relays are energized and the High Bat relay is de energized In response to a Low Bat or AC Fail condition the appropriate normally ener gized relay Low Bat or AC Fail drops out In re sponse to a High Bat condition the normally de en ergized High Bat relay is energized Auxiliary Relay Option Optional auxiliary relays provide contacts for ener gizing external alarms remote indicators and con trol equipment such as louver motors and water pumps Alarm Module Option The optional alarm module Figure 2 7 provides an audible indication that the transfer switch has trans fe
29. ter cio iii ee ne ae er 4 3 B lterEBSe IE harge cui a en en od 4 3 AWARNING INCORRECT SERVICE OR REPLACEMENT OF PARTS CAN RESULT IN DEATH SEVERE PERSONAL INJURY AND OR EQUIPMENT DAMAGE SERVICE PERSONNEL MUST BE QUALIFIED TO PERFORM ELECTRICAL AND OR MECHANICAL SERVICE Safety Precautions This manual includes the following symbols to indi cate potentially dangerous conditions Read the manual carefully and know when these conditions exist Then take the necessary steps to protect per sonnel and the equipment This symbol warns of Immediate hazards that will result In severe personal Injury or death This symbol refers to a hazard or unsafe practice that can result In severe per sonal Injury or death A CAUTION This symbol refers to a hazard or unsafe practice that can result In personal In jury or product or property damage High voltage in OT transfer switch components pre sents serious shock hazards that can result in se vere personal injury or death Read and follow these suggestions Keep the transfer switch cabinet closed and locked Make sure only authorized personnel have the cabinet and operational keys Due to the serious shock hazard from high voltages within the cabinet all service and adjustments 40 the transfer switch must be performed only by an electrician or authorized service representative If the cabinet must be opened for any reason 1 Move the operation selector switch on the gen erator
30. transfer switch requires servicing con tact your nearest dealer or distributor Factory trained Parts and Service representatives are ready to handle all your service needs If unable to locate a dealer or distributor consult the Yellow Pages Typically our distributors are listed under GENERATORS ELECTRIC ENGINES GASOLINE OR DIESEL OR RECREATIONAL VEHICLES EQUIPMENT PARTS AND SERVICE 1 2 For the name of your local Cummins Onan or Onan only distributor in the United States or Can ada call 1 800 888 ONAN This automated serv ice utilizes touch tone phones only By entering your area code and the first three digits of your local telephone number you will receive the name and telephone number of the distributor nearest you For the name of your local Cummifis only distribu tor or if you need more assistance please call Onan Corporation 1 612 574 5000 7 30 AM to 4 00 PM Central Standard fime Monday through Friday When contacting yourdistributor always supply the complete Model Numbef and Serial Number as shown on the nameplate Cummins is a registered trademark of Cummins Engine Company Onan is a registered trademark of Onan Corporation 2 Description Automatic transfer switches control transfer of the load to the Normal power source or to the Emer gency power source generator set without opera tor involvement Throughout this manual frequent references are made to two wire and three wire
31. ule sends a signal to the time delay module that initi ates and controls the timing for generator set start and the transfer of load The standard transfer switch has undervoltage sensing for all phases of the Normal and Emer gency power sources Overvoltage and Frequency Sensing Option Overvoltage and frequency sensing are available as a single option Overvoltage Sensing gt With optional overvoltage sensing the Normaliand Emergency sources are monitored for an Overvoltage condition As with the standard undervoltage sensing the voltage sensors signal the time delay module which Contr lsithe transfer or retransfer sequence An adjustable time delay 0 to 120 seconds over rid s momentary overshoots in voltage To set this time delay align the slot on the potenti ometer with the desired marking onthe Power Sen try Cover Frequency Sensing With optional frequency sensing the Normal and Emergency sources are monitored for variations in frequency The sensors determine whether the source is within an adjust able bandwidth As with the standard undervoltage sensing the fre quency sensors signal the time delay module which controls the transfer or retransfer sequence An adjustable time delay 0 to 15 seconds allows the control to ignore momentary dips or rises in fre quency To set this time delay align the slot on the potenti ometer with the desired marking on the Power Sen try cover Two Wire Sta
32. uto matic starting circuit 1 Correct the engine starting problem 2 Push the Overcrank Reset button inward and release to reset the overcrank relay PREVENTIVE MAINTENANCE Performing the yearly preventive maintenance procedures in Table 3 1 will result in operational reliability of the transfer switch The following procedures must only be performed by technically qualified personnel following the proce dures provided in the Service manual 962 0512 If repair or replacement of components is necessary call your dealer or distributor AC power within the cabinet and the rear side of the cabinet door presents a Shock hazard that can cause severe personal Injury or death In addition incorrect installation service or parts replacement can result In severe personal injury death and or equipment damage Therefore all cor rective service procedures must only be performed by technically qualified personnel following the procedures provided in the Service manual 962 0512 The transfer switch presents a shock hazard that can cause severe personal Injury or death unless all AC power Is removed Be sure to move the generator set operation selector switch to Stop disconnect AC line power disconnect the battery charger fromits AC power source and dis connect the starting battery negative lead first before servicing Ignition of explosive battery gases can cause severe personal Injury Do not smoke or cause any spark arc or fl
33. vided that the Test With Without Load switch Figure 2 2 is in the With Load position Moving the switch to Normal causes the load to retransfer to the Normal power source after the retransfer time delay To avoid the delay and cause a fast retransfer of load to the Normal power source move the switch to the Retransfer position Optional Meter Package The optional meter package includes an AC amme ter an AC voltmeter a frequency meter and a phase selector switch AC Voltmeter The voltmeter measures line to line voltage of the selected power source AC Ammeter The ammeter measures the line cur rents of the load Frequency Meter This meter measures the out put frequency of the selected power source in hertz Phase Selector Switch This switch is used to se lect the source and phase to be measured Optional Auto Manual Switch The Auto Manual switch is used to enable or dis able the automatic retransfer funetion This switch has two positions In the Auto position normal auto matic retransfer is enabled inthe Manual position automatic retransferAfrom a functioning generator set back to utility powef is disabled only manual retransfer using the TesUNormaRetransfer switch is possible In the event of generator set failure however the Power Sentry control logic will ignore the Auto Manual switch and initiate retrans fer to utility power TRANSFER SWITCH The transfer switch Figure 2 2 opens and
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