Technical Manual
hD8625 8-
5
/
8
” 35K Tong
7.5
hyDraulic coMponenTs
Technical Information - Two Speed Motor
DISPLACEMENT CHANGE
When a motor is shifted from full to partial displacement the
motor is changed to 50%, 35%, or 28% of its original
displacement depending on its shift ratio.
STANDARD SHIFT RATIO
The standard 15 Series displacements of 15, 13, 9.5, 8, 7,
and 6 CID are available in the 15 Series Two Speed with a
shift ratio of 2:1. For example, a 15 CID motor shifted to
partial displacement becomes a 7.5 CID motor.
SPECIAL SHIFT RATIOS
There are two special displacements available in the 15
Series Two Speed which offer higher shift ratios, the 10.5
and the 11.5 CID. The 10.5 CID motor has a shift ratio of
3.5:1, which when shifted becomes a 3 CID motor. The 11.5
CID motor has a shift ratio of 2.875:1, which when shifted
becomes a 4 CID motor.
SHIFTING METHOD
Selecting between full and partial displacement is
accomplished by shifting the two-position spool valve
incorporated in the motor. Motors are available in either
single or double pilot configurations.
SINGLE PILOT
Single pilot motors require a pilot line to be connected to port
"C". When port "C" is pressurized the spool shifts the motor
to partial displacement. When port "C" is vented to tank, an
internal spring shifts the spool, returning the motor to full
displacement.
DOUBLE PILOT
Double pilot motors require two pilot lines. One line is
connected to port "C" while the other line is connected to
port "D". The motor is in full displacement when port "D" is
pressurized and port "C" is vented to tank. The motor is in
partial displacement when port "C" is pressurized and port
"D" is vented to tank.
OPEN DURING CROSSOVER SPOOLS
Open during crossover spools allow port "A" to be directly
connected to port "B" when the spool is shifting between full
and partial displacement. Motors with -62 or -65 designations
are open during crossover.
WARNING! IN SOME WINCH APPLICATIONS, OPEN
DURING CROSSOVER SPOOLS (-62 or -65) ARE NOT
RECOMMMENDED.
CLOSED DURING CROSSOVER SPOOLS
Closed during crossover spools do not allow port "A" to be
directly connected to port "B" when the spool is shifting
between full and partial displacement. Motors with -63 or -67
designations are closed during crossover. These motors
contain an internal factory preset relief valve. This valve
protects the motor during shifting only and is not a system
relief valve.
PILOT PRESSURE
A minimum of 100 PSI over case drain pressure is required to
shift the spool. The maximum allowable pressure to port "C" or
"D" is 3,500 PSI.
SHIFT ON THE RUN
The 15 Series Two Speed Motor may be shifted on the run
while loaded or unloaded.
MAXIMUM SPEED
Maximum rated speed is the same for either full or partial
displacement as stated in the performance data.
CASE DRAIN AND CROSS PORT LEAKAGE
The combined case drain and cross port leakage of the 15
Series Two Speed Motor is approximately 1 GPM per 1,000
PSI. This will vary with the oil viscosity.
OTHER INFORMATION
All other information as specified under Techinal Information
also applies to the 15 Series Two Speed Motor. (See page 5)
Cross Section - Two Speed Motor
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