TM 9-4940-421-14
AR 701536
Figure 2-2. Air compressor drive motor controls, air receiver tank pressure gage and pressure switch
The service light switch (fig
reset switch will automatically disengage when a
l. Service Light Switch.
mechanical or electrical malfunction occurs in the air
panel.
system that causes the electrical circuit to be over-
loaded.
amount of air pressure in the air receiver tank. During
q. External Power Receptacle. The external power
normal operation it should read between 80 psi and 100
receptacle (fig 2-3) provides 115 volts ac single-phase
psi.
power to operate equipment.
r. Overspeed Safety Switch. The overspeed safety
operated electric switch that automatically starts and
switch (fig 2-4) will break the ignition circuit at 2140
stops the air compressor to maintain a minimum of 80
rpm or 68 hertz. To reset the overspeed safety switch,
psi and a maximum of 100 psi.
shut ignition switch off and restart engine.
s. High Temperature Safety Switch. As a safety pre-
safety device to protect the air system and personnel if
caution against overheating, a high temperature safety
a malfunction occurs that would cause the pressure in
switch has been mounted to the cylinder head at no. 2
the system to exceed a safe working pressure. The pop-
spark plug. The safety switch will automatically stop
off valve will open to let the air pressure escape from
the engine by shorting out the ignition system. A wait-
the system when the air pressure of 135 psi is reached.
ing period of about 15 minutes will be required before
p. Start, Stop and Reset Switch. The switch (fig 2-2)
the switch has cooled off sufficiently to restart the
is used to start and stop the air compressor system. The
engine.
