With the engine running in high idle (EPG ON), the belt-driven primary hydraulic pump P1 in
the engine area is turning and pumping hydraulic fluid throughout selected components in the
ECU. The 24 Vdc, 200 amp system of the ECV provides the DC operating power for the CBPS.
The 24 Vdc voltage is applied to the inverter which provides a 115 Vac output for the CBPS AC
Under full CBPS load conditions, a maximum of 3,412 watts (142 amps) is possible. Since the
system is powered by a 200 amp generator, the remaining 58 amps should be adequate for
ECV systems and battery charging.
External Power. External AC power is normally provided by connecting the 10 kW TQG on the
HMT to the LMS power panel; however, any equivalent or greater 208 Vac, 3-phase external
source may be used. The AC input power from the 10 kW TQG is applied to CBPS components
including the AC motor A2M1 in the compartment on passenger side of ECV. The AC motor
drives a hydraulic pump P2. The hydraulic pump P2 pumps hydraulic fluid through selected
components of the ECU. AC is also applied to the converter 1A4A14 which provides the DC
operating power for the CBPS. Because the hydraulic system in the external mode is incapable
of providing the heat required by the system, AC electric heaters located in the ECU are used to
heat the CBPS.
b. LMS. During the deployment of the ABS, the LMS crew operates the controls and indicators for
inflating and pressurizing the ABS and sets the environmental temperature within the CBPS. The
LMS crew also monitors alarm indicators on the ECC and ensures that air is supplied to ABS.
Environmental Control. The ECU components are powered by the hydraulic system. Venting,
heating and cooling equipment housed in the ECU is controlled by ESS mode selector switch located
on rear control panel. Outside air is drawn into the ECU via vent (NBC) fan, directed through the
dust/water separator (vortex generator), through a plenum in ECU, to three NBC gas particulate
filters. The filtered air goes into a port where it is mixed with filtered return air from the LMS. The
recirculating blower motor fan directs the air across the heating coils or air conditioning fins for
heating or cooling. The air is blown into the soft air duct of the LMS and through the cloth duct of
the ABS. When in the cool mode, the air conditioner condenser coil is cooled by passing air over the
condenser coil and blowing the air out of the ECU with the condenser fan located on the driver's side
of the ECU.
Also located in the ECU is the rib fan used to inflate air beams. Air generated by the rib fan is
passed through a flexible hose in the LMS to the rib manifold in the ABS. The rib manifold connects
to each air beam and contains a check valve and shut-off valve. The check valve automatically stops
airflow from the air beam. The shut-off valves can be used to isolate a selected air beam for
maintenance purposes. A small hose from the air beam manifold to a fitting on the LMS is used for
measuring air beam pressure.
d. ABS. The ECV tailgate is lowered and the ABS is unrolled, inflated and secured with lines and
stakes. Before the air beams of the ABS can be inflated, it is necessary to verify that the turn-off
valves on the air beams are opened and the outside air beam dump caps are properly secured. Under
normal conditions, the rib blower motor will be on when the air beam pressure is 1.5 psi or lower and
will turn off when the pressure reaches 2.9 psi.
For NBC operation, the entire CBPS should be decontaminated. (Refer to FM 3-11.5.) The
ambulatory and TALP entry ways must be kept securely sealed to keep the contaminated outer
surfaces of the ABS from contaminating the interior of the ABS or LMS. For protection against
contaminants, the ABS should not be inflated lower than 0.5 inches of water, gage (iwg).