Hobart 140GT17P Operation And Maintenance Manual With Illustrated Parts List page 37

(b) Contactor control switches
• This is another three-position, toggle switch identical to the engine-generator control
switch. When placed in the spring loaded CLOSE position, it provides 115-V AC power di-
rectly to a rectifier which supplies DC power for closing the load contactor. When released
it returns to the normal ON position and continues to provide power to the rectifier, but in
this switch position, AC power must pass through the plug interlock and fuse interlock re-
lays. In OFF position the switch opens the AC circuit to the rectifier, thereby cutting off the
source of DC power to the contactor coil which allows the contactor to open.
(c) Instrument light and switch
• A shielded, instrument panel light (2) is mounted at the left side of the control panel. It is
controlled by a rocker switch (17) , which also controls instrument lights on the control box
and clearance lights on the canopy of the generator set.
(d) Engine starting circuit
• The pushbutton start switch (16) and permissive rocker switch (14) serve to connect power
for closing an auxiliary solenoid switch. The auxiliary switch then connects power to the
starter solenoid which functions to engage the starter gear with the flywheel ring gear and
apply power to the starter motor to crank the engine. The auxiliary solenoid switch is neces-
sary because the start pushbutton switch is not capable of carrying the high amperage flow
to the starter solenoid which would result if the starter gear and ring gear should fail to en-
gage. The permissive rocker switch (14) also stops the engine when the toggle is placed in
the down (STOP) position.
(e) Indicating lights
• A green indicating light (13) glows to indicate that power is available to the engine protec-
tive system. The light operates only when the engine is running and fuel pressure is suffi-
ciently high to close a fuel pressure switch. The purpose of the pressure switch is to
deactivate the protective circuit when the engine is stopped and prevent battery discharge.
• Two other green indicating lights (9 and 10) glow when the generator output load contactor
is CLOSED and power is available at the generator output terminal panel
(f) Engine circuit breaker
• A 10-ampere circuit breaker (8) protects the 12VDC engine control circuit, hourmeter, illumi-
nating light circuit, and 12VDC system in the main generator protective system.
(g) Air cleaner indicator
• The air cleaner indicator (18) is mounted on the engine control panel for easy viewing. Its
function was explained in Para. 7, C, (4) (see Fig. 4).
September 30/89 Revised
OM-2029
1-1
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