CHAPTER 3 GENERATOR SET CONTROLS REPAIR INSTRUCTIONS

CHAPTER 3 GENERATOR SET CONTROLS REPAIR INSTRUCTIONS Section I. INTRODUCTION 3-1. General. 3-2. Generator Set Controls Description. This chapter includes repair instructions for the The generator set controls are mounted at the rear fault indicator panel and the control cubicle. Test of the set, and provide all monitoring and control procedures for the control cubicle include individual devices required to operate the set. Controls con- tests for the converter, control box, relay assem- sist of the fault indicator panel, the control cubicle, bly, frequency meter and transducer, ac wattmeter and the manual throttle control. Refer to the Oper- and ac ammeter. ator and Organizational Maintenance Manual for manual throttle control repair instructions. Section II. FAULT INDICATOR PANEL 3-3. Removal, Disassembly and Repair, a. Removal. Refer to Operator and Organiza- tional Maintenance Manual and remove the fault indi- cator panel. b. Disassembly. See figures 3-1 and 3-2 and disassemble the fault indicator panel. c. Repair. Proceed as follows — (1) Clean all components with low pressure compressed air, or wipe clean with dry, lint free cloth. (2) Inspect for broken fuseholders, cracked or broken lamp holders, damaged wire insulation, bro- den wires and bent or broken connector pins. (3) Remove any components that show visual damage, such as broken fuseholder, or broken lamp holder (fig. 3-1). (4) Replace circuit board if broken, cracked or distorted. (5) Resistors may be checked by breaking con- nection at one end to prevent feedback resistance and touching both ends with ohmmeter probes. Re- sistors R1 through R10 (fig. 1-2) should read 2. 2K ohms ±10 percent. Resistors R11 through R20 should read 1K ohms ±10 percent. Any variation in excess of 10 percent indicates that the resistor should be replaced. If any connections are opened or bared for test purposes or if any defective com- ponents are replaced, the affected area must be coated with polyurethane resin to prevent oxidation or other corrosion. The coating must be of a mini- mum thickness of O. 007 inches and air bubble entry into the applied polyurethane must be controlled so that the legibility of component coding and identifica- tion is not impaired. The polyurethane resin to be utilized will correspond to MIL-I-46058 grade S, Type PUR. (6) Unplug relay 17, (fig. 3-1) in fault indica- tor panel and check resistance of relay coils with ohmmeter probes across pins 3 and 7. Reading should be 300 ohms ±10 percent. Replace relay if variation exceeds 10 percent. Plug relay into cir- cuit board. (7) Rebuild wiring harness if inspection re- veals 30 percent or more defective wires. Wiring harness rebuilding instructions are described in Chapter 5. Otherwise replace damaged wires. 3-4. Reassembly, Testing and Installation. a. Reassembly. See figures 3-1 and 3-2 and re- assemble the fault indicator panel. b. Testing. See figure 1-2. To test the fault in- dicator panel, proceed as follows: (1) Connect 24Vdc, positive to pin A of ter- minal board. (2) Connect 24Vdc negative to pin B and case. (3) Operate reset switch. All lights should light. (4) Connect pin C to pin D. Low oil pressure light should light. (5) Open C to D connection. Low oil pressure lights should remain on. (6) Connect pin C to pin E. Low oil pressure light should remain on. (7) Operate reset switch. Low oil pressure light should go out and overspeed switch should light. 3-1