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1. To set the time delay align the slot on the potenti ometer with the desired marking on the faceplate Figure 2 3 Ifa 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 time while operating a signal contact to give warning that a transfer or retransfer is about to occur This op tion is typically used in elevator applications This module also provides three other sets of form C signal contacts The Signal Module has one adjustable timer The Elevator Signal delay controls the timing of two events It delays transfer retransfer and energizes the Elevator Transfer Signal relay during the delay period This time delay is adjustable over a range of O to 50 seconds 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 2 5 Timing an i Seconds 60 Program Transition e FIGURE 2 3 PROGRAM TRANSITION MODULE B ay Signal Module 16 Timing Delay Seconds SAC 50 FIGURE 2 4 SIGNAL MODULE Alarm Module Option The optional alarm module Figure 2 5 provides an audible indication that the transfer switch has trans ferred to the sourc2. 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 All calibration 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 The most important component of the electronic control system is the Power Sentry control Figure 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 AWARNING 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 Power Sentry Time Delays Transfer Time Delay This delay prevents nui sance transfers to the backup power source caused by brief line fluctuations After the delay the transfer switch transfers the load to the backup power source It has anadjust ble range of O to 120 seconds To set th
3. O 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 Thentakethe 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 This symbol refers to a hazard or unsafe practice that can result In personal in jury or product or property damage High voltage in 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 to the transfer switch must be performed only by an electrician or authorized service representative If the cabinet must be openedfor any reason re move AC power to the automatic transfer switch If the instructions reguire 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 electrical equipment Do not wear damp clothing pa
4. ct assemblies between the Normal sOurce 1 power source and the Emergency source 2 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 inthe Op eration 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 source 1 and Emergency source 2 sides of the transfer switch They are actuated by operation of the transfer switch during transfer and retransfer The Normal side auxiliary contact switch is actu ated when the transfer switch is in the Normal posi tion The Emergency side auxiliary contact switch is actuated when the transfer switch is in the Emer gencyposition The auxiliary contacts have current ratings of 10 amperes at 250 VAC OPTIONAL OPTIONAL POWER SIGNAL PROGRAMMED SENTRY MODULE TRANSITION CONTROL INDICATOR LAMPS OPTIONAL METERS SWITCHES ACCESSORY CONTROL PANEL MOTOR AUTOMATIC DISCONNECT TRANSFER SWITG SICH SC1581 28 FIGURE 2 2 INTERIOR COMPONENTS ELECTRONIC CONTROL SYSTEM This section describes the standard and optional components of the electronic control
5. e 2 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 in the Source 2 Connected position If the horn is silenced the Horn Silenced lamp will also light Both lamps will stay lit until the transfer switch moves from the Source 2 Connected position to the disconnected neutral or Source 1 Connected po sition 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 FIGURE 2 5 ALARM MODULE 3 Operation AUTOMATIC OPERATION The automatic transfer switch is set for automatic operation by placing the Motor Disconnect switch on the Accessory Control Panel in the Auto posi tion Place the Source Selector switch in the desired po sition MANUAL OPERATION The transfer switch has operator handles for manu ally transferring the load Use the following proce dure 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 If possible remove all AC power to the transfer switch before manually operating the switch if It Is necessary to perform manual operatlon with AC power connected follow the Safety Related Work Practices lis
6. e Selector Switch is replaced with a three position spring return to center switch 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 voltmetermeasufes line to line voltage of the selected powersource 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 souree and phase to be measured TRANSFER SWITCH The transfer switch Figure 2 2 opens and cloSes the contacts that transfer the load between Normal and Emergency power The transfer switchis 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 the current flow When closed to either the Normal or the Emergency power source the contacts are mechanically held A mechanical interlock preventsithem from closing to both power sources at the same time Linear Actuator The linear actuator is a linear induction motor that moves the conta
7. ear 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 quallfied 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 disconnect AC line power before servicing TABLE 3 1 ANNUAL PREVENTIVE MAINTENANCE 1 DISCONNECT ALL SOURCES OF AC POWER Disconnect both AC power sources from the transfer switch before continuing 2 CLEAN a Thoroughly dust and vacuum all controls meters switching mechanism components interior buswork and connecting lugs b Close the cabinet door and wash exterlor 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 supporting hardware_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 section 4 of the Service manual 962 0512 Check system hardware for loose connections Tighten as indicated i
8. in the United States or ada call 1 800 888 ONAN This automated sarv 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 Cumminseonly 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 Time Monday through Friday When contacting your distributor always supply the complete Model Number and Serial Number as shown on the nameplate Cummins is agegistered trademark of Cummins Engine Company Onan is a registered trademark of Onan Corporation 2 Description Automatic transfer switches control transfer of the load to either Normal power source source 1 orto Emergency power source source 2 without op erator involvement 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 Source 1 Available andsSource 2 Available lamps are lit whenever their corresponding power sources are producing power These two lamps can be lit simultaneously The Source 1 Connected lamp is lit when the auto matic transfer switch Siin the Source 1 normal po sition The Source 2 Gonnected lamp is lit when the au
9. is time delay align the slot on the potenti ometer with the desired marking on the Power Sen try cover Retransfer Time Delay This delay begins the mo ment the preferred source voltage and freguency return After the delay the transfer switch can retransfer theload to the preferred source The de lay allows the preferred source to stabilize before retransfer It has an adjustable range of O to 30 minutes To set this time delay align the slot on the potenti ometer with the desired marking on the Power S n try cover Undervoltage Sensing Two voltage sensors one for the Normal side and one for the Emergency side monitor source volt ages for an undervoltage conditiom and generate signals which are sent to the time delay module If for example an undervoltage Condition is sensed on the Normal source the v ltage sensor module sends a signal to the time delay module that initi ates and controls the transfer of load The standard OT Ill has undervoltage sensing for all phases of the Normal and Emergency power sources Overvoltage and Frequency Sensing Option Overv ltage and frequency sensing are available as a single option Overvoltage Sensing With optional overvoltage sensing the Normal and Emergency sources are monitored for an overvoltage condition AS With the standard undervoltage sensing the voltage sensors signal the time delay module which controls the transfer or retransfer sequence An adj
10. n step 4 Check all control wiring and power cables especially wiring between or near hinged door for signs of wear or deterioration Check all control wiring and power cables for loose connections Tighten as indicated in step 4 Check the cabinet interior for 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 Retorgue all cable lug connections Lugsterque tequirements are listed in section 1 of the Service manual 5 CONNECT AC POWER AND CHECK OPERATION a Connect the both AC power sources b Test systemperation as described in this section Close and lock the cabinet door 4 Troubleshooting The following procedures describe preliminary troubleshooting checks If the trouble persists 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 For this reason do not touch or allow clothing tools or jewelry to contact ex posed electrical terminals whenever the cabl net door Is open Make sure you are standing on a dry Insulating surface TRANSFER SWITCH DOES NOT TRANSFER AUTOMATICALLY 1 Check the Motor Disconnect switch It should be in the Auto position 2 Is the Source Selector switch in the correct
11. po sition 3 Has the transfer time delay expired 4 Has the programmed transition time delaya if equipped expired 5 Is backup source voltage sufficient to trigger the backup source voltage sensor 4 1 TRANSFER SWITCH DOES NOT RETRANSFER AUTOMATICALLY Check the Motor Disconnect switch It should be in the Auto position Isthe Source Selector switch in the correct po sition Has the retransfer time delay expired Has the programmed transition time delay if eguipped expired Is preferred source voltage sufficient to trigger the preferred source voltage sensor
12. rticularly wet shoes or allow skin surfaces to be damp when handling any electrical equipment Jewelry iS a good conductor of electricity and should be removed when working on the electrical equipment Do not work on this equipment when mentally or physically fatigued or after consuming alcohol or any drug that makes the operation of equipment unsafe OTS UU 3 1 Introduction OPERATOR S MANUAL This manual provides information necessary for operation of an OT Ill transfer switch with an auto matic utility to utility control The utility to utility control automatically directs transfer of the load from one utility power source to another providing nearly continuous power TRANSFER SWITCH APPLICATION Transfer switches are an essential part of a build ing s standby or emergency power system The Normalpowersource source 1 is backed up by an Emergency power source source 2 A transfer switch supplies 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 conditions 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 power source The transfer and retransfer of the load are the two most basic functions of a transfer Swi
13. tch AUTOMATIC TRANSFER SWITCHES Automatic transfer switches capable of automatic operation without operator involvement perform the following basic functions 1 Sense the interruption of the Normal power source 2 Transfer the load to the Emergency power source 3 Sense the return of the Normal power source 4 Retransfer the load to the Normal power source SOURCE 1 SOURCE 2 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 If it is 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 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 For the name of your local Cummins Onan or Onan only distributor
14. ted In NFPA 70E 1 Open the cabinet door of the automatic trans fer switch 2 Move the Motor 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 lower manual operator handle down Retransfer from the Emergency to the Nor mal power Source C Pulkthe lower manual operator handle up D Push the upper manual operator handle Before moving the Motor Disconnect switch back to the Auto position remember the trans fer switch willtransfer load to the active power source If both power sources are available it will transfer the load to the preferred source Automatic transfer switch op eration results In rapld movement of the manual operator handles and presents a hazard of severe personal Injury Keep hands clear of handles when switching back to automatic operation Move the Motor Disconnect switch to the Auto position 6 Close and lock the cabinet door 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 r
15. to matic transfer switch is in the Source 2 emer gency position SOURCE 1 CONNECTED LAMP SOURCE 1 AVAILABLE LAMP Onon Transfer Switch PHASE SELECTOR SWITCH FOR OPTIONAL METERS OPTIONAL AUTO MANUAL SWITOH SOURCE 2 CONNECTED LAMP SOURCE 2 AVAILABLE LAMP OPTIONAL AC VOLTMETER M OPTIONALAC AMMETER OPTIONAL FREQUENCY METER a SOURCE SELECTOR SWITCH M1694 28 FIGURE 2 1 CABINET WITH OPTIONS Source Selector Switch This two position switch is used to select which source is preferred and which source is the backup Inthe Source 1 position the Normal power source supplies the load power until a power interruption occurs In the Source 2 position the Emergency power source supplies the load power until a power inter ruption occurs Optional Auto Manual Switch The optional Auto Manual switch is used to enable or disable the automatic retransfer function This switch has two positions In the Auto position nor mal automatic retransfer is enabled In the Manual position automatic retransfer from the non pre ferred source back to the preferred source is dis abled only manual retransfer using the Preferred Source Selector switch is possible In the event of power source failure however the Power Sentry control logic will ignore the Auto Manual switch and initiate retransfer to the other source When the optional Auto Manual switch Is Installed the standard Sourc
16. unen iehe Operator s Manual OT Ill Transfer Sw itch 00 Amperes 40 to 10 y Ut ty to Ut 962 0115 6 8 Printed in U S A Table of Contents SECTION TITLE PAGE 1 INTRODUCTION 1 1 Operators Manual gt 2 sd cect as ky ia dr ien 1 1 Transfer Switch Application eee 1 1 Automatic Transfer Switches Re II 1 1 Model Identification 9 1 2 How to Obtain Service esos Ses ed ie 1 2 2 DESCRIPTION 4 2 1 Cabinet cu GAs Eram ge eee ee ee e ebur 2 1 Transfer Switch na re Nena 2 2 Electronic Control System 2 4 3 OPERATION ca ESI NN een 3 1 Automatic Operation EN 3 1 Manual Operation 3 1 Preventive Maintenance 3 2 4 TROUBLESHOOTING 0 RD onenn anere nrnnnrnrrerennrn 4 1 Transfer Switch Does Not Transfer Automatically 4 1 Transfer Switch Does Not Retr nsfer Automatically 4 1 INCORRECT SERVICE OR REPLACEMENT OF PARTS CAN RESULT IN DEATH SEVERE PERSONAL INJURY AND OR EQUIPMENT DAMAGE SERVICE PERSQNNEL MUST BE QUALIFIED T
17. ustable time delay 0 to 120 seconds over rides momentary overshoots in voltage To set this time delay align the slot on the potenti ometer with the desired marking on the 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 Programmed Transition Option The optional Program Transition module Figure 2 3 is used to introduce a pause during transition Programmed transition allows the transfer switch to assume a mid transition position for an adjustable interval of time In this position the load is notcon 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 time that the transfer switch is in the midposition can be adjusted from 0 to 7 5 seconds or 0 to 60 seconds depending on the timer option The proper adjustment is a func tion of the load
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