THEORY OF OPERATION
This work package contains functional descriptions of the generator set and explains how TQG functional systems interact
with one another.
ENGINE STARTING SYSTEM
The engine starting system consists of two 12-volt batteries connected in series, a 24 Vdc starter, a 24 volt battery charging
alternator, a magnetic pickup (for sensing engine speed) and the related switches and relays required for control of the
starting system. The PUSH TO STOP EMERGENCY STOP pushbutton on the EMCP will automatically disable the starting
system and shut down the TQG if it is pushed in. For engine cranking, battery power is supplied to the starter motor through
the starter solenoid which in turn is controlled by the EMCP. The starter engages the engine flywheel causing the engine to
crank. As the engine accelerates to above idle speed (sensed by the magnetic pickup), the EMCP disengages the starter. The
starting sequence may also be stopped by moving the ENGINE CONTROL switch on the EMCP to COOL DOWN/STOP.
The engine may be cranked without starting by engaging the DEAD CRANK SWITCH. The DEAD CRANK SWITCH is a
three-position switch. Up position is CRANK, the center position is OFF, and the lower position is NORMAL (operation).
With the DEAD CRANK SWITCH in CRANK position, the starter motor is energized without activating any other starting
or control function. With the switch in the OFF center position, the system is off. With the switch in NORMAL (operation)
position, the TQG will crank and start. The batteries are charged by the belt-driven battery charging alternator. The
battery charging alternator also supplies GSC power. Normal operating indication depends on the state of charge in the
batteries. A low charge, such as exists immediately after engine starting, will cause a high reading. Cold outside
temperatures make starting the engine difficult. To improve engine starting in cold weather the engine contains a 78A inlet
air preheater. This heater is described in the Air Intake and Exhaust System paragraph.