DRAFT
TM 5-4210-249-13&P-1
0003
120/240 VAC HYDRAULIC GENERATOR SYSTEM
The TFFT is equipped with a complete electrical power system. Output of generator is controlled by an internal
hydraulic system. An electrical instrument gauge panel (right rear) stowage box is provided for operator to monitor
and control all electrical operations and outputs.
Generator utilizes main chassis transmission to power generator. Generator is driven by engine transmission PTO
unit, through a hydraulic pump and motor. An electric/hydraulic valve supplies hydraulic fluid to clutch engagement
unit provided on chassis PTO drive. Main load center is equipped with circuit breakers rated to load demand.
Individual breakers are provided for all on-line equipment to isolate a tripped breaker from affecting any other on-
line equipment.
WINTERIZATION PACKAGE
A winterization package is provided to allow operation of the pump, foam system, and body up to -25F (-32C).
The package includes two diesel-fired 27,300 BTU heaters, one inside the pump compartment and one used to
heat the rear compartment. The heaters turn on at 39F (4C).
Two (2) 2,250 W water heaters are installed in the water tank. The tank heaters turn on at 40F (4C) and turn off
at 60F (16C). Some of the plumbing from the water tank to the pump is protected from freezing with heat trace
tape and insulation.
PRESSURE GOVERNOR
The pressure governor is designed to maintain a selected water pump pressure or water pump engine speed
setting. When the water pump engine is powered up, the water pump engine will remain at idle until the MODE
switch is pressed to select the desired operating mode, RPM mode, or PRESSURE mode.
When the pressure governor is in RPM mode, MESSAGE CENTER will display THROTTLE and the green RPM
LED will be illuminated. Water pump engine speed is controlled by the INCrease (INC) and DECrease (DEC)
switches, MESSAGE CENTER will display INCREASE or DECREASE as appropriate when these switches are
depressed. The water pump engine will maintain an RPM appropriate for the throttle signal being sent. If, while
operating in RPM mode, the pressure increases more than 50 psi (345 kPa) from the pressure logged at the last
switch pressed, the pressure governor will limit the pressure increase to no more than a 50 psi (345 kPa)
difference. The pressure governor may reduce water pump engine RPM to ensure pressure difference. PSI LIMIT
will be displayed in MESSAGE CENTER. The pressure governor will not attempt to regulate pressure in this
mode, only limit the pressure difference to 50 psi (345 kPa) from the pressure present when the last switch was
pressed.
When the pressure governor is operating in the PRESSURE mode, MESSAGE CENTER will display PRESSURE
and the amber PRESSURE LED will illuminate. Water pump pressure is set by using the INCrease and DECrease
switches. The pressure governor will attempt to maintain the last pressure achieved with these switches.
MESSAGE CENTER will display INCREASE or DECREASE as appropriate. The pressure governor maintains
water pump pressure by controlling water pump engine RPM in response to a signal from the pressure
transducers. When controlling in this manner, MESSAGE CENTER will display CTRL DEC or CTRL INC.
Pressing PRESET switch in either mode will control the water pump engine to attain the preset RPM or water pump
pressure programmed in the pressure governor memory. If there is more than 10 psi (69 kPa) pressure on the
water pump, the RPM preset is disabled and MESSAGE CENTER will display DISABLED.
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