CHAPTER 6 MAINTENANCE OF CONTROL SYSTEM

TM 5-6115-584-34 NAVFAC P-8-622-34 TO-35C2-3-456-2 TM-05682C-34 CHAPTER 6 MAINTENANCE OF CONTROL SYSTEM Section I. 6-1. DC CONTROL SYSTEM. DESCRIPTION AND FUNCTION 6-3. VOLTAGE REGULATOR. Refer to the Operator and Organizational Maintenance Excitation current is controlled through the static type Manual for the description and function of the dc control automatic voltage regulator. The voltage regulator contin- system. uously compares the output voltage of the synchronous generator with a stable reference voltage. The difference between the two voltages constitutes an error signal which 6-2. AC INSTRUMENTATION SYSTEM. indicates an output voltage that is higher or lower than the generator set point. This error signal is amplified and Refer to the Operator and Organizational Maintenance used to control the direct current output of the voltage Manual for description and function of the ac instrumen- regulator which is applied to the control windings of the tation system. current-voltage transformers. Section II. MAINTENANCE 6-4. CONTROL CUBICLE. a. Wiring Harness. (1) Remove. Disconnect wires of wiring harness from all components. Remove clamp attaching harness to control panel and remove harness. (2) Repair. Table 6-1 lists the wire number, gauge, color, length and terminal lugs for each wire in the harness. Repair consists of replacing wires as required. (3) Installation. Install harness by connecting wires to components per figure 6-1. Attach harness to control panel with clamp. b. Meters (on equipment test). (1) Frequency Meter (M3) (16, figure 6-3). Con- nect a frequency meter of known accuracy to single phase output terminals of load terminal board. Make certain reconnection switch is in proper position for single phase output. Operate Generator Set and check readings of panel meter (M3) against test frequency meter. If panel meter does not give the same reading as the test meter, test transducer as given in (2) below. (2) Frequency Transducer (A3) (56, figure 6-3). Test transducer using the same procedure as for testing frequency meter. If transducer does not give proper meter reading, replace the transducer and/or the meter. (3) Percent Current Meter (M4) (17, figure 6-3). Connect an ac test ammeter in series with the % rated current meter. Operate Generator Set with a single phase load. Continue adding load to set until meter reads 0.75 amps. Meter (M4) should read 100% ± 2% . Replace meter if necessary. (4) AC Voltmeter (M5) (18, figure 6-3). Attach test ac voltmeter in parallel (across terminals) with panel ac voltmeter (M5). Operate Generator Set and compare readings of the two meters. Panel voltmeter must be ac- curate to ± 2.5%, except between 115 and 125 volts, accuracy must be ± 3 volts and between 200 and 250 volts, accuracy must be ± 5 volts. If panel meter does not meet these requirements, replace meter. c. Meters (remove). (1) Frequency Meter (M3) (16, figure 6-3). Tag and disconnect two leads from meter. Remove three screws, lockwashers, and nuts attaching meter to panel and remove meter. (2) Frequency Transducer (A3) (56, figure 6-3). Tag and disconnect four leads to frequency transducer. Remove four screws (54) and nuts (55) attaching trans- ducer to back of control cubicle and remove transducer. (3) Percent Current Meter (M4) (17, figure 6-3). Tag and disconnect two leads from meter. Remove three screws, lockwashers, and nuts attaching meter to control panel and remove meter. 6-1