TM 5-3895-356-14&P
Plumbing and associated hardware have been minimized
Check for External Leaks: Hoses and fittings should be
by building the charge pump and check valves into the
checked regularly for leaks. Watch for cracks or wear
pump cover. The high and low pressure relief valves
replace when indicated.
and the shuttle valve are built into the motor. Therefore,
Change: Oil should be changed if color of hydraulic fluid
no separate hoses or connections are needed for these
changes, and once a year in any case. Use filtered or
items.
strained oil of correct type.
B. Operation
CAUTION
The pump operating control changes the amount and
Running the system with an inadequate oil
direction of flow. When the pump's variable cam is
supply can cause damage to the parts.
moved from neutral, oil flows from the pump to the
Reservoir should be checked daily for
motor through the main system lines. This causes the
presence of water or emulsification of oil. It
motor to rotate. The oil discharged from the motor is
presence is noted, completely drain and flush
returned directly to the inlet of the pump.
system. Refill with NEW oil. (Filter or strain
Moving the pump control through neutral (over center) to
as directed above.)
the reverse position causes the motor to reverse direction
FILTER:
by changing the side of the system develop high pressure
Under no circumstances should the suction filter on the
fluid. Either side of the system can be the high pressure
Dynapower charge pump be allowed to by-pass, thus
side. System valving provides proper operation and
permitting contaminants to enter the closed loop.
protection automatically when the system reverses.
Those filter units which have a by-pass feature should
Oil is supplied directly from the reservoir, through the filter,
have a spring or block installed to prevent any by-passing.
to the charge pump. It is discharged through one of the
Prior approval of the filter element manufacturer should
two check valves to charge the row pressure side of the
be obtained for this type of installation in the remote
system. This same oil also supplies pressure for the
possibility that the element might collapse under vacuum.
control, makeup and cooling oil to the closed system and
If it is determined by the filter element manufacturer that
inlet pressurization. Pressurization is maintained by the
the by-pass feature must be incorporated, the unit should
low pressure relief valve which relieves excess oil to the
have an 8-10 PSI minimum by-pass.
reservoir.
Note
See Figure 101.
If system contains a shut-off valve, (this is
The pilot-operated high pressure relief valve protects the
highly recommended) in the line between the
system from oversurges or extremely high-starting
filter and the reservoir, make doubly certain it
pressures. In order not to deplete the closed system of oil,
is open again prior to starting.
this high pressure relief valve discharges to the low
Change: Change filter after first 25 hours; then after each
pressure side of the system.
600 hours, or more frequently if dirt conditions of the
A pressure-actuated shuttle valve is used to direct both
particular installation make it desirable. If indicator-type
high and low pressure to the respective relief valves.
filter is used, change when indicator shows need.
When one line is high pressure, it moves the shuttle valve
Also: If a magnetic filter or screen is installed in the
towards the flow pressure side; this in turn ports the high
reservoir outlet, check and clean when changing filter
pressure to its relief valve. At the same time it ports the
element.
low pressure side to its relief valve. It is also the valve
CAUTION
used to direct the high pressure relief valve discharge to
Before re-starting system, check oil supply
the low pressure side of the system.
level in the reservoir. Damage can occur if
The ability of the pump to go "over center" has eliminated
system is run with an inadequate oil supply.
the need for four-way valves for reversing the motor.
Make sure shut-off valve is open.
C. Basic Care of the System
OPERATION INSPECTION
FLUID
Make a daily inspection of the entire installation.
The Dynapower transmission is designed to use and is
CLEANING
warranted with Type A suffix A automatic transmission
If it becomes obvious that cleaning is necessary, then
fluid as there are no fluids designed for 5000 PSI
remove complete system and flush with low pressure
operation.
steam or solvent. Upon completion of an overhaul
All other fluids should be submitted to the factory for
operation, flush system as directed above before
possible approval on specific applications.
reinstallation.
Check Reservior: Fluid supply should always be at
Note
specified level. If necessary to add, use correct type of
Never use pressures or heat sufficient to
filtered or strained oil. Reservoir should be checked every
damage the hoses or other rubber parts of the
4-5 hours on the first day of use, twice a day for the first
system. When steam is used, precautions
week and every day thereafter.
must be taken to remove all moisture from the
system.
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