Owner Manual Automatic Transfer Switch RA Series RA112L1 (Spec A) English Original Instructions 7-2019 A052S254 (Issue 3)
Table of Contents 1. IMPORTANT SAFETY INSTRUCTIONS ....................................................................................... 1.1 Warning, Caution, and Note Styles Used in This Manual ..................................................... 1.2 General Information ................................................................................................................ 1.2.1 General Precautions ..................................................................................................
Table of Contents 7-2019 5.2.2 Transfer Switch Mechanism Removal ....................................................................... 5.2.3 Transfer Switch Replacement.................................................................................... 5.2.4 Reconnect AC Power (When Finished) ..................................................................... 5.3 Control Relay (K1) Replacement Procedure ........................................................................ 5.
1 Important Safety Instructions Save these instructions. This manual contains important instructions that should be followed during installation and maintenance of the transfer switch. Safe and efficient operation can be achieved only if the equipment is properly operated and maintained. Many accidents are caused by failure to follow fundamental rules and precautions. 1.
1. Important Safety Instructions 7-2019 Follow these guidelines while working on or around electrical equipment. • Place rubber insulated mats on dry wood platforms over metal or concrete floors when working on any electrical equipment. • Do not wear damp clothing (particularly wet shoes) or allow skin surfaces to be damp when handling any electrical equipment. • Remove all jewelry when working on electrical equipment. • Wear safety glasses whenever servicing the transfer switch.
-2019 1. Important Safety Instructions 4. Remove utility power to the automatic transfer switch. If the instructions require otherwise, use extreme caution due to the danger of shock hazard. WARNING AC power within the cabinet presents a shock hazard that can cause severe personal injury or death. A052S254 (Issue 3) 3 Copyright © 2019 Cummins Inc.
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2 Introduction 2.1 Owner Manual This manual covers models produced under the Cummins® Power Generation (CPG) brand names. This manual provides information necessary for operation, installation, and service of RA series RA112L1 transfer switches. This manual also includes parts information. This is an open transition transfer switch which does not include an integral automatic transfer switch control. With an open transition switch, there is never a time when both sources are supplying power to the load.
2. Introduction 7-2019 FIGURE 1. RA112L1 AUTOMATIC TRANSFER SWITCH 2.2 Transfer Switch Application Transfer switches are an essential part of a building's standby or emergency power system. The utility line (normal power), is backed up by a generator set (emergency power). The transfer switch connects the electrical load to the utility or generator set. The load is connected to the common of the automatic transfer switch, as shown below.
7-2019 No. 2. Introduction Description No. Description 1 Utility (Normal Power) 4 Over Current Protective Device 2 Over Current Protective Device (Customer Supplied) 5 Generator Set (Emergency Power) 3 Load FIGURE 2. LOAD TRANSFER SWITCH (TYPICAL FUNCTION) 2.3 Transfer Switch Function Automatic transfer switches, capable of automatic operation without operator intervention, perform the basic function of transferring the load to the available power source.
2. Introduction 2.4 7-2019 Model Identification The model number, serial number, and electrical characteristics are shown on the nameplate. The nameplates for the RA Series transfer switches are located on the inner back of the enclosure near the bottom. Refer to the table below for the meaning of the model number characters. TABLE 2.
7-2019 2. Introduction Refer to www.cummins.com/support and select Sales and Service Locator, or send an email to ask.powergen@cummins.com. A model and date code label (shown below) is located on the on the inner back of the enclosure near the bottom. FIGURE 3. MODEL AND DATE CODE LABEL 2.6 Application and Installation Installations must be carefully planned and correctly installed for proper operation. This involves two essential elements: application and installation.
2. Introduction 7-2019 Application refers to the design of the complete standby power system that usually includes power distribution equipment, generator sets, transfer switches, mounting pads, and fuel systems. Each component must be correctly designed so the complete system functions as intended. Application and design is a technical function generally done by trained specialists.
3 Installation 3.1 Installation Overview These installation recommendations apply to typical installations. Whenever possible, these recommendations also cover factory designed options or modifications. However, because of the many variables in any installation, it is not possible to provide specific recommendations for every situation. If there are any questions not answered by this manual, contact your nearest Cummins/Onan distributor or authorized dealer for assistance. 3.1.
3. Installation 7-2019 RA Series transfer switches are only designed to be installed with the generator set models identified in Section 2.1 on page 5. Installing this switch with any other generator set model will void the warranty and may result in the transfer switch not working properly. 3.2.2 Equipment Inspection and Storage Once you have received the transfer switch, inspect it for any damage.
7-2019 No. 3. Installation Description No. Description 1 Utility Source 5 Circuit Breaker 2 Utility Panel 6 Generator Set Source 3 Loads not backed up by generator set 7 Loads backed up by generator Set 4 Transfer Switch 8 Automatic transfer switch 9 Circuit Breaker* * Use only Square D Type QO for the branch circuit breakers. FIGURE 4. PARTIAL COVERAGE SYSTEM A052S254 (Issue 3) 13 Copyright © 2019 Cummins Inc.
3. Installation 7-2019 TABLE 4. APPROXIMATE CABINET DIMENSIONS Switch Current Rating 100 Amp 3.2.5 Height Width Depth Weight 38.0 in (965 mm) 14.25 in (362 mm) 4.0 in (102 mm) 40 lb (18.1 kg) Mounting Method RA Series transfer switches are mounted to a wall. Enough room must be allowed to remove the door panel for inspection and servicing of the switch, as per NEC and local codes. 3.2.5.1 Wall Mounting 1.
7-2019 3. Installation When installing conduit, observe the following precautions: • The RA Series transfer switch includes multiple knockouts in the cabinet for ease of wiring. If you decide to drill your own holes instead of using the knockouts provided, cover the transfer switch and both terminal blocks to prevent accidental entry of metal chips before beginning conduit installation.
3. Installation 7-2019 FIGURE 5. TRANSFER SWITCH AC CONNECTIONS LOCATION (TB5) TABLE 5. SCREW TYPE TERMINALS AND TORQUE VALUES Number of Terminals Tightening Torque Range Wire Size in-lb Nm 50 5.6 1/0 - 3 50 5.6 4-6 45 5.1 8 40 4.5 14 - 10 35 4.0 6 25 2.8 14 - 8 10 1.1 6-4 35 4.0 8 25 2.8 14-10 2020 2.
7-2019 3. Installation Number of Terminals Tightening Torque Range Wire Size in-lb Nm 6-4 35 4.0 8 25 2.8 14 - 10 20 2.3 Two 14 or 12 CU, two 12 AL 25 2.8 Two 14 AL 25 2.8 28 - 32 3.2 - 3.6 7 0.8 24 (1 wire per terminal) 14 - 4 TB5 1 cable per pole 14 - 1/0 TB4 26 - 12 3.3.2 Low Voltage Signal Connections 3.3.2.1 Control Wiring Connections Control wiring connections are made at terminal block TB4, located in the center of the transfer switch enclosure.
3. Installation No. 7-2019 Description 1 Control Relay (K1) 2 Utility Sense Relay (K2) No. 3 Description TB4 FIGURE 6. CONTROL WIRING CONNECTIONS 3.3.2.2 Connecting the Transfer Switch to the Generator Set WARNING AC voltages and currents present an electrical shock hazard that can cause severe personal injury or death. Disconnect the AC power source. Make sure the generator set is not running and cannot be started. Disconnect the batteries and open the generator set mounted circuit breaker.
7-2019 3. Installation Wire resistance must not exceed 0.5 Ohm per line. Use stranded or solid wire. For connection to the screw terminal, strip the insulation back 3/8 in (10 mm). 3.3.3 Final Inspection and Cleanup Prior to energizing the transfer switch: 1. Inspect all wiring to be certain that: • All connections are correct. • All generator set start low voltage signal connections are correct (refer to drawings at the end of this manual and in the generator set manual).
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4 Troubleshooting 4.1 Introduction This section describes troubleshooting issues, as well as the sequence of events for the automatic transfer switch. 4.2 Troubleshooting Procedures for Experienced Service Personnel This section describes a typical transfer switch sequence of events, and provides detailed troubleshooting procedures for experienced service personnel. The troubleshooting procedures use schematics and symptoms to diagnose all possible problems.
4. Troubleshooting 7-2019 2. Relay K2 energizes, opening K2-11 and K2-12, which removes the run command from the generator set control. 3. After the retransfer delay, the generator set control de-energizes the relay coil (K1), which closes K11/K1-9 and K1-2/K1-10 and opens K1-7/K1-11 and K1-8/K1-12 to move the transfer switch from the Generator set position to the Utility position. 4.
7-2019 4. Troubleshooting WARNING Improper operation of the generator set presents a hazard that can cause severe personal injury or death. Observe all safety precautions in your generator set manuals. TABLE 7. TROUBLESHOOTING THE TRANSFER SWITCH (PROBLEM #1) Problem The transfer switch failed to transfer to the generator set. Possible Causes Corrective Actions 1. The K1 relay coil may not have received a signal from the controller.
4. Troubleshooting 7-2019 TABLE 8. TROUBLESHOOTING THE TRANSFER SWITCH (PROBLEM #2) Problem The transfer switch failed to transfer to the utility. Possible Causes Corrective Actions 1. The utility source may not be present. 1. Check to see that the Utility service disconnect (circuit breaker) is in the ON position. 2. Make sure that the feeder breaker to the transfer switch is on. 3. Check for a ground (B-) signal on TB4-1. 2.
5 Transfer Switch Service 5.1 Introduction This section covers the removal and replacement procedures for transfer switch components. NOTICE For servicing purposes, each transfer switch mechanism is removed and replaced as a single component; there are no serviceable sub-components. 5.2 Switch Removal and Replacement Procedure 5.2.1 Disconnect AC Power WARNING The transfer switch is a shock hazard that can cause severe personal injury or death unless all AC power is removed.
5. Transfer Switch Service 7-2019 c. If there is a battery charger, disconnect the battery charger from its AC power source. d. Disconnect the generator set starting battery negative (-) cable. e. Remove all AC power to the automatic transfer switch by turning off the feeder breaker in the main house panel. f. Remove AC power from any accessory such as battery heater, oil heater, etc. 5.2.2 Transfer Switch Mechanism Removal 1. Remove the upper and lower covers. 2.
7-2019 5. Transfer Switch Service WARNING Ignition of explosive battery gases can cause severe personal injury. Do not smoke or cause any spark, arc, or flame while servicing batteries. WARNING Batteries emit hydrogen, a highly explosive gas. Thoroughly ventilate the battery compartment before connecting battery cables. Connect the negative (-) cable (s) first to reduce the risk of arcing. 3. Reconnect utility power (Normal). 4. Reconnect generator set power (Emergency). 5.
5. Transfer Switch Service 7-2019 WARNING Accidental starting of the generator set can cause severe personal injury or death due to electrocution or contact with moving parts. Disconnect the starting battery cables, before performing service. Batteries emit hydrogen, a highly explosive gas. Thoroughly ventilate the battery compartment before removing battery cables. Remove the negative (-) cable (s) first to reduce the risk of arcing. c.
7-2019 5. Transfer Switch Service WARNING Accidental starting of the generator set can cause severe personal injury or death due to electrocution or contact with moving parts. Disconnect the starting battery cables, before performing service. Batteries emit hydrogen, a highly explosive gas. Thoroughly ventilate the battery compartment before removing battery cables. Remove the negative (-) cable (s) first to reduce the risk of arcing. c.
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Appendix A. Parts Information Table of Contents Figure 7. RA112L1 Automatic Transfer Switch Model .............................................................................. 32 Table 10. RA112L1 Automatic Transfer Switch Model ............................................................................. 33 A052S254 (Issue 3) 31 Copyright © 2019 Cummins Inc.
Appendix A. Parts Information 7-2019 This section includes information on replaceable parts used with RA transfer switches. FIGURE 7. RA112L1 AUTOMATIC TRANSFER SWITCH MODEL Copyright © 2019 Cummins Inc.
7-2019 Appendix A. Parts Information TABLE 10. RA112L1 AUTOMATIC TRANSFER SWITCH MODEL Ref No. Part No. Qty.
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Appendix B. Wiring Diagrams Table of Contents Figure 8. RA112L1 Automatic Transfer Switch Wiring Diagram (Sheet 1) ............................................. 37 Figure 9. RA112L1 Automatic Transfer Switch Wiring Diagram (Sheet 2) ............................................. 38 Figure 10. RA112L1 Automatic Transfer Switch Interconnection Diagram (Sheet 1) ........................... 39 Figure 11. RA112L1 Automatic Transfer Switch Interconnection Diagram (Sheet 2) ...........................
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7-2019 Appendix B. B.0 Wiring Diagrams RA112L1 Automatic Transfer Switch Wiring Diagram FIGURE 8. RA112L1 AUTOMATIC TRANSFER SWITCH WIRING DIAGRAM (SHEET 1) A052S254 (Issue 3) 37 Copyright © 2019 Cummins Inc.
Appendix B. Wiring Diagrams 7-2019 FIGURE 9. RA112L1 AUTOMATIC TRANSFER SWITCH WIRING DIAGRAM (SHEET 2) Copyright © 2019 Cummins Inc.
7-2019 Appendix B. B.1 RA112L1 Automatic Transfer Switch Interconnection Diagram FIGURE 10. A052S254 (Issue 3) Wiring Diagrams RA112L1 AUTOMATIC TRANSFER SWITCH INTERCONNECTION DIAGRAM (SHEET 1) 39 Copyright © 2019 Cummins Inc.
Appendix B. Wiring Diagrams 7-2019 FIGURE 11. Copyright © 2019 Cummins Inc.
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