TM 10-5410-228-24
When the hydraulic circuit is in the vent mode (figure 1-25) and air beam pressure is reduced to below 1.5
psi for any reason, the rib fan motor, M4, is automatically turned on. This is accomplished by applying +24
Vdc to the coils of solenoid valves SV2, SV5, SV7, and SV8. SV2, SV5, and SV8 are opened and SV7 is closed.
This diverts the hydraulic fluid flow away from the condenser fan, M1C, and through the rib fan motor, M4.
The speed of the rib fan is controlled by flow control FP5 which diverts hydraulic fluid flow around the rib
fan motor to limit its speed and pressure for safety. When air beam pressure is increased to 2.9 psi, the
system is returned to the previous condition.
Valve
SV1
SV2
SV4
SV5
SV6
SV7
SV8
SV9
Energized State
OFF
ON
OFF
ON
ON
ON
ON
OFF
Position
Closed
Open
Closed
Open
Open
Closed
Open
Open
Figure 1-28. Static Mode, External Power, Rib Fan On, NBC Off