ARMY TM 9-6115-604-12NAVY NAVFAC P-8-633-12(3)Air box shutdown relays L2A and L2B will energize to close the air control valves in the air intakeduct lines to the engine air intake manifold. The engine, cut off from its air supply, will deceleratevery rapidly. Solenoids L2A and L2B are not rated for continuous duty, air box disconnect switchOP3 will disconnect the solenoids from ground as soon as failing engine oil pressure allows OP3 toopen. When OP3 does open, solenoids L2A and L2B deenergize. The back-EMf caused by theircollapsing fields will be shorted by diode CR3. This prevents arcing from occurring at the contacts ofpushbutton S7.i.EMERGENCYSHUTDOWNControl. The EMERGENCY SHUTDOWN control is mounted on the left sideof the skid base below the engine compartment access doors. It is a mechanical pull which cuts off fuel tothe engine. The resulting loss of engine speed rapidly leads to the tripping of a shutdown circuit as thevoltage and frequency output of generator G1 falls.4-20. MAINTENANCE OF BATTERY CHARGER . Battery charger BC1 provides 24 V dc to charge the generator setbatteries. Maintenance of the battery charger consists of testing, adjustment, and replacement.a.Test See Figure 4-26.(1)Test the ac input fuse ACF and dc output fuse DCF as follows:(a)Set BATTERY CHARGER circuit breaker CB116 to OFF.(b) Remove the ac input fuse ACF and dc output fuse DCF from the fuse board inside the batterycharger BC1.(c) Using a multimeter set to the RX1 scale, check continuity across both fuses. Multimeter shouldindicate zero resistance.(2)Test the dc AMMETER A as follows.(a)Set BATTERY CHARGER circuit breaker CB116 to OFF.(b)Remove battery charger leads from the battery.(c)Install a multimeter set to read dc amps across + and - output leads from the battery chargerBC1.(d)Set BATTERY CHARGER circuit breaker CB116 to ON and set equalizer TIMER ET to ON.(e)DC AMMETER A reading should be within 5 percent of multimeter installed In step b, above.(f)Reinstall battery charger leads.(3)Test Input and output voltages as follows:(a)Set BATTERY CHARGER circuit breaker CB116 to OFF.(b)Install a multimeter set to read AC volts across the input leads to battery charger BC1.(c)Set BATTERY CHARGER circuit breaker CB116 to ON.(d)AC multimeter reading should be 120 V ac.(e)Set BATTERY CHARGER circuit breaker CB116 to OFF.(f)Install a multimeter set to read dc volts across the + and - output leads from battery chargerBC1.(g)Set BATTERY CHARGER circuit breaker CB116 to ON and set equalizer TIMER ET to ON.(h)Multimeter should read 27 2 V dc.b.Remove. See Figure 4-26.(1)Set BATTERY CHARGER circuit breaker CB116 to OFF.(2)Tag and disconnect wiring to the battery charger BC1 (5).(3)Remove the battery charger BC1 (5) and drip shield cover (4) by removing hexagonal nuts (2), lockwashers (3), and vibration isolators (1) at base of the battery charger BC1. Loosen the hexagonal nuts (2)and lock washers (3) at the top of the battery charger BC1, and lift the battery charger BC1 upward andaway from the upper vibration isolators (1).4-72
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