TM-9-2350-311-20-1

HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5

TECHNICAL MANUAL; UNIT MAINTENANCE MANUAL FOR HULL, POWERPLANT, DRIVE CONTROLS, TRACKS, SUSPENSION, AND ASSOCIATED COMPONENTS

AUGUST 1994

TM-9-2350-311-20-1 - Page 254 of 1275

TM

9-2350-311-20-1

3-3 TROUBLESHOOTING CHART —

CONTINUED

m. ALTERNATOR CIRCUIT (M109A2/M109A3)

The alternator circuit consists of the alternator, voltage regulator, rectifier, master relay, vehicle batteries, circuit breaker,

portable instrument panel, battery indicator gage, and air cleaner blower relay.

When the MASTER switch is turned ON, 24 Vdc is supplied through the circuit breaker to the master relay. Voltage is

also supplied to the voltage regulator through the air cleaner blower relay. When the engine is cranked and oil pressure

reaches 4 to 8 psi (28 to 55 kPa), the air cleaner blower relay and the master relay close. This closes a circuit in the

voltage regulator and the generator begins operating and supplying voltage to charge the batteries and operate all

electrical components on the vehicle.

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