19
LUBRICATION
Under normal service conditions the motor, gearing,
bearings, and parts are all pre-lubricated and should
not require periodic maintenance. If for any reason the
unit is disassembled in the field, all oilite bushings
should be resaturated with an SAE-10, non-detergent
oil and all gearing heavily coated with Amoco Rykon
Premium Grease #2 or equivalent grease. Care should
be taken to ensure that no foreign material is allowed
to become combined with the grease in the gear train,
which will cause premature failure. Keep gearbox
clean and dry.
DRAG BRAKE ADJUSTMENT
The drag brake serves two functions: a) to prevent
actuator from backdriving at maximum rated torque;
and b) to allow the motor shaft to slip when
handcranking and the output shaft load is in excess of
rated torque.
The drag brake was factory set and should not need
readjustment. If it does need adjustment:
1. Apply an overhung load, equal to the maximum
torque rating to the output shaft.
2. Loosen drag brake jam nut until the motor shaft
starts to backdrive.
3. Tighten the drag brake jam nut just enough to
prevent backdriving.
4. While handcranking against the load, increase the
load until motor backdriving occurs.
Maintenance
TORQUE LIMIT SWITCH ALIGNMENT
The torque limit switches are factory set and field
adjustment is not advised unless proper test equip-
ment is available. If adjustment must be done, use the
following procedure:
1. Load the output shaft with a known load which
matches the torque rating of the actuator in an
opposing direction for the switch being adjusted.
2. Apply power to the motor and run the actuator to
drive the opposing load.
3. Increase the load by 5% to 10% and adjust the set
screw (140C) to trip the torque switch.
4. Remove the 5% to 10% increase of load and the
switch should reset.
5. Load the actuator in the opposite direction and set
the other switch in the same manner.
NOTE: When looking at the torque limit switch
assembly as it is mounted in the actuator, the switch
on the top of the assembly controls the CW torque
and the switch on the bottom controls the CCW
torque. The torque should be set near equal for both
directions.
When the actuator is driven into a torque condition
in the CW direction (looking at the output shaft), the
handcrank handle will move slightly outward. For
CCW direction the handle will pull slightly inward.
Summary of Contents for SM-1715
Page 23: ...23...
