Manual

Page 33 of 64 General Machine Products Co., Inc.
PROCEDURE FOR SETTING THE RELIEF VALVE AND PRESSURE SWITCH FOR CA-
BLE SIZES 6-12 OD
When installing small diameter cables with “soft/flexible” characteristics, it will be necessary to
reduce the pressure relief valve and pressure switch settings to prevent the cable buckling or
being jammed in the air chamber mounted collet. The pressure relief valve should be set to
1015 psi (70 Bar). The pressure switch should be set to 870 psi (60 Bar) (For very “soft/
flexible” cables the above values may have to be reduced proportionally to enable successful
installation.)
TO SET PRESSURE RELIEF VALVE FOR SMALL DIAMETER (UNDER 12MM)
OR FLEXIBLE CABLE
Clamp a piece of 1” O.D. dowel/round bar x 13” long between top and bottom housings so it
butts up to the air chamber mounted collets (in effect placing the motors in stall mode).
Note: The below procedure will put the unit in a hydraulic bypass condition and will rapidly
heat the oil. Try to keep the time in bypass to a minimum as the heated oil could change your
readings.
1. Connect and start the power pack. With the electric control panel switched “off”, turn hy-
draulic on/off valve to the “on” position.
2. Rotate the speed control knob fully clockwise to “MAX” and observe pressure gauge read-
ing of approximately 1600 psi (110 Bar).
3. Adjust pressure relief valve (see fig. 1) until the pressure gauge pointer drops to 1015 psi
(70 Bar).
4. Rotate the speed control knob counter-clockwise (towards “MIN”) until the pressure gauge
reads 0 Bar.
5. Rotate the speed control knob again, fully clockwise to “MAX” and re-check pressure
gauge reading of approximately 1015 psi (70 Bar).
6. Re-adjust the relief valve slightly if needed until 1015 psi (70 Bar) is indicated on the
gauge. Finally tighten the relief valve lock nut while preventing the relief valve adjustment
from turning.
7. Rotate the speed control knob again, fully clockwise to “MAX” and re-check the pressure
reading of approximately 1015 psi (70 Bar) after lock nut is tightened. If different, readjust.
Pressure Relief Valve
Lock Nut
Adjusting Screw
Figure 1
Speed Control