TH-57B ELECTRICAL SYSTEM
Identify the three sources of electrical power for the TH-57B.
External Power Unit
State the power rating of the battery.
24 volt,17 ampere hour
State the generator output.
Rated at 30 Volts, 150 amp
Regulated to 28 volts, 105 amp
State the purpose of the voltage regulator used in the generator system.
Maintains constant generator voltage under varying loads.
State the purpose of the overvoltage sensing relay.
Trips the generator reset relay, disconnecting the generator from the circuit, when line voltage reaches 31±1 volts.
State the purpose of the reverse current relay.
Connects generator to common BUS only when proper voltage is obtained
Prevents current flow from the battery to the generator
Disconnects the generator from the common BUS when voltage drops below a safe level
Identify the component that allows the generator to function as a starter.
State when the igniters receive power.
When the field control relay is actuated
State the power requirements for an engine start when using external power.
28 vdc 400 amp
Recall the circumstances necessary to illuminate the battery caution lights.
54oC ±3o BATTERY TEMP caution light illuminates
60oC ±3o BATTERY HOT caution light illuminates
State the loadmeter and voltmeter indications that would signify a generator failure.
Load Meter 0 Voltmeter 22 to 24 volts