Hobart 6921 Series Operation And Maintenance Manual page 35

OM-2040 / Operation and Maintenance Manual
90D20 / Generator Sets
d. Indicating lights
A green indicating light (13, Fig. 11) 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 (19, Fig. 4) . The purpose of the pressure
switch is to deactivate the protective circuit when the engine is stopped and prevent
discharge.
e. Fuel gage and blocking diodes
An electric fuel gage (7, Fig. 11) receives a signal from the sending unit mounted on the fuel
tank. Twelve-Volt DC operating power is supplied to the fuel gage system. To check fuel
quantity while engine is stopped, use switch (6) to turn ON panel lights.
A blocking diode (10, Fig. 14) , located on the back of the fuel gage, prevents feedback from
the alternator into the engine circuitry.
f. Cold weather starting aid control (Optional)
The push-button control (11, Fig. 11) operates a cold weather starting aid. The starting aid
consists of a group of items designed to inject a highly volatile fluid into the engine air intake
system. This assists ignition of fuel when air temperature is too low for the heat of
compression to ignite a normal fuel mixture. The starting aid consists of a cylindrical fluid
container and a valve (see 6, Fig. 3) which are mounted on the panel separating the
generator from the engine. The valve is operated by the control (11, Fig. 11) allowing fluid to
flow into the valve. Pushing the button IN forces fluid through a small tube and an atomizing
nozzle into the inlet manifold. The addition of atomized, highly volatile fuel into the inlet air
assists in igniting the diesel fuel mixture.
g. Engine stop control
The engine is normally stopped by use of the 3 position switch. Top position is START,
middle is RUN and bottom position is STOP.
h. Air cleaner indicator
The air cleaner indicator (See 1, Fig. 12) is mounted on the engine test panel. Its function
was explained in Para. 5, (3), See Fig. 5.
i. Test receptacle connector
This amphenol connector ( 1, Fig. 12) provides an attaching point for leads which are
connected to selected test points throughout the engine and generator electrical systems.
Connections and schematic diagrams indicate points at which the leads are connected. The
receptacle connector is designed to mate with a test box plug connector (See Fig. 15) .
February 28/94
Revised
Chapter 1-1
Page 17