TM 5-3805-258-24-1
OPERATOR'S STATION
INDIVIDUAL CIRCUIT DESCRIPTION
SYSTEMS OPERATION
MAIN POWER CIRCUIT
The machines have a standard disconnect switch that is in the engine com-
partment by the left rear tire. This switch is to be used only when work is done
on the electrical system, or the machine is left unattended for long periods of
time. These machines have a key switch (OFF-ON-START) on the instru-
ment panel. When the key switch is turned to either the ON or START posi-
tions, the main power relay is activated. The main power relay sends power
to most of the electrical system through a 60 amp auto-reset circuit breaker.
There is an 8 amp auto-reset circuit breaker in the circuit which sends power
to the key switch.
Diode A, in the 2V9473 Diode Assembly, is used so that the main power relay
will not activate if the batteries are connected backwards. This will prevent
reverse polarity damage to the alternator.
Diode B, in the 2V9473 Diode Assembly, is used to keep the main power relay
activated while the engine is in operation, even if the key switch is turned OFF.
The main power relay will keep activated as long as the engine runs fast enough
for the alternator to make enough voltage to keep it activated. The main power
relay must be activated while the engine is in operation, to keep the battery load
on the alternator.
CAUTION
There can be damage to the alternator if the engine is run (with the
alternator connected) without the battery load on the alternator.
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