Hobart 90 C 20 Operation And Maintenance Manual page 38

OM-2031
(d) Engine starting circuit
The pushbutton start switch (15) and permissive toggle switch (18) serve to connect power for closing
an auxiliary solenoid switch. The auxiliary switch then connects power to the starter solenoid which func-
tions 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 necessary 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 engage. The permissive toggle switch (18) also stops the engine when the toggle is
placed in the down (STOP) position.
(e) Indicating lights
A green indicating light (14) glows to indicate that power is available to the engine protective system.
The light operates only when the engine is running and fuel pressure is sufficiently 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.
Another green indicating light (9, Fig. 9) glows when the generator output load contactor is CLOSED
and power is available at the generator output terminal panel (13, Fig. 3).
(f) Cold weather starting aid control
The push-pull control (11) controls operation of a cold weather starting aid (Fig. 3). The starting aid
consists of a group of items designed to inject a highly volatile fluid into the engine air intake system to as-
sist ignition of fuel when air temperature is too low for the heat of compression to ignite a normal fuel mix-
ture. The starting aid consists of a cylindrical, fluid container and a valve (see 1-3, Fig. 4) which are
mounted on the lifting yoke. The valve is operated by the control (11, Fig. 9) . Pulling the control outward
allows fluid to flow into the valve. Pushing the control IN forces fluid through a small tube and an atomiz-
ing nozzle into the inlet manifold. The addition of atomized, highly volatile fuel into the inlet air assists in ig-
niting the diesel fuel mixture.
(g) Fuse
A 10-ampere fuse (13) protects the 12-V DC engine control circuit, hourmeter, illuminating light circuit,
and 12-V DC system in the main generator protective system.
(3) Air cleaner indicator
The air cleaner indicator (12) is mounted on the engine control panel for easy viewing. Its
function was explained in Para. 6, C, (3) (see Fig. 6).
(4) Test receptacle connector
This Amphenol connector (19) provides an attaching point for leads which are connected
to selected test points throughout the engine and generator electrical systems. Connec-
tions and schematic diagrams indicate points at which the leads are connected. The re-
ceptacle connector is designed to mate with a test box plug connector (see Fig. 12).
1-1
Page 22
April 30/96 Revised