TM 11-7440-278-14
CHAPTER 5
FUNCTIONING OF THE EQUIPMENT
5-1.
Hydraulic Console, Controls and Indicators
Control or Indicator
Function
C (L3) is excessive, the heater operates the overload
START PUMP MOTOR
Starts pump motor to develop
switch, opening the circuit to the relay coil. To operate
switch
fluid pressure for movement
the system again, the RESET switch must be operated
of the equipment rack.
before depressing the START switch. Depressing the
STOP PUMP MOTOR
Stops the pump motor.
STOP switch opens the circuit from the L1 line to the
switch
relay coil, allowing the relay contacts to open.
IN pushbutton
Moves equipment rack against
the van wall.
OUT pushbutton
Moves equipment rack to the
5-3.
Hydraulic System, Fluid Flow
center of the van.
a. When power is applied to the motor pump,
pressure is built-up in the tank. Operation of the OUT
OIL PRESS gauge
Indicates the pressure in the
switch operates the control valve to allow the fluid from
hydraulic system.
the tank to flow from the B side of the valve. The fluid is
OIL LEVEL gauge
Indicates the amount of fluid
forced through a flow divider and into the rear section of
in the hydraulic system tank.
the hydraulic cylinder. The fluid pressure forces the
equipment rack to move away from the van wall. This
forces the fluid in the front section of the cylinder to
5-2.
Hydraulic System Theory of Operation
return through the second flow divider and the control
The three phase power from circuit breaker CB7 of the
valve to the tank.
black power distribution panel is applied to the magnetic
b. When the IN switch is operated, the fluid flow is
starter. Depressing the console START switch applies
in the A direction and the return is from the B section of
208 volts to the starter relay coil, causing its contacts to
the cylinders.
close and apply-ing the three phase power to the
hydraulic pump motor. In addition, phase A (L1) power
is ap-plied to the IN and OUT switches through the
STOP switch. Depressing the OUT or IN switches
5-4.
Major Components
operates their associated control valves, allowing the
Refer to the applicable technical manuals in appendix A
output pressure to move the No. 4 equipment rack. If
for an explanation of the functioning of the other major
the current through the heater in phase
components comprising the AN/MYK-8 (V) (*).
5-1
