TM 9-6115-729-24
0003
AIR INLET AND EXHAUST SYSTEM - Continued
engine will crank and try to start normally. During engine cranking, if the sum of the coolant temperature
and the inlet manifold temperature is less than 109F (25C), the heater will be turned on. The heater will remain
on during cranking. If the engine fails to start, the heater will revert to preheat and the heater will come on for 30
seconds. After the engine has started, if the sum of the coolant temperature and the inlet manifold temperature is
less than 109F (25C), the heater will remain on continuously for 7 minutes. If the same temperature conditions
exist afterwards, the heater will remain on for 13 minutes, turning on for 10 seconds and turning off for 10
seconds. After the 13-minute heat cycle, the heater will turn off. If the coolant temperature sensor fails, the
heater will activate if the inlet manifold air temperature is less than 50F (10C). If the inlet manifold temperature
sensor fails, the heater will activate if the coolant temperature is less than 104F (40C). After the engine has
been running, if the sum of the coolant temperature and the inlet manifold temperature does not exceed 127F
(35C), the heater will be activated again. The heater will be activated for no more than 20 minutes at a time.
The normal current draw of the air inlet heater is 77 to 95 amps.
AC POWER OUTPUT
The AC output system (Figure 7) consists primarily of the AC generator, the output load terminal board, the
voltage reconnection terminal board, the main load contactor and the AC CIRCUIT INTERRUPTER switch on the
EMCP. Power created by the AC generator is supplied through the voltage reconnection terminal board and
the main load contactor to the output load terminals on the output load terminal board. The voltage reconnection
terminal board allows configuration of the generator set for 120/208 volt connections or 240/416 volt connections.
The DVR and GSC must be reprogrammed for voltage changes. The AC CIRCUIT INTERRUPTER switch
located on the EMCP closes and opens the main load contactor. This enables or interrupts the power flow
between the voltage reconnection terminal board and the output load terminals. The main load contactor is
also opened automatically during any of the specified set faults. The Digital Voltage Regulator (DVR) module in
the EMCP senses AC generator output voltage and provides excitation voltage to the AC generator to maintain
the desired output voltage. The VOLTAGE adjust potentiometer is connected to the DVR to allow minor voltage
adjustments. The user can select which output load terminals to monitor for current and voltage measurements
with the GSC keypad AC METER key. The values and terminals are indicated on the upper and lower displays.
Refer to AC POWER DISTRIBUTION for a more detailed discussion.
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