Flowserve L120 Series Limitorque Actuation Systems - Manual (Page 25)

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Limitorque Actuation Systems L120 Series FCD LMENIM1201-04-AQ – 05/15
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5.3 Motor Operation
The actuator is always available for motor operation whenever the motor is energized
a CAUTION: Do not force the declutch lever into motor operation. Lever will automatically return to
motor operation when the motor is energized.
Reset the travel limit switches prior to motor operation if the actuator has been dismantled or removed
from the valve.
Piece numbers refer to Figure 5.2.
In motor operation, the Motor Gear Set (piece 35 and 38) drives the Wormshaft (piece 15) and Worm
Gear (piece 21) which in turn rotates the Clutch Sleeve (piece 19) by means of driving the lugs. The
clutch sleeve and worm gear may be assembled to produce either a “no lost motion” or “hammerblow”
effect. The Drive Sleeve (piece 25) is keyed to the clutch sleeve and hence rotates, producing the
required output rotary motion.
5.4 Torque and Travel Limiting
The geared limit switch is driven by a bevel gear connected to the upper drive lugs of the clutch sleeve.
The limit switch is directly connected to the output of the actuator. Once properly set, the limit switch
remains in step with the valve position regardless of electric or manual operation of the Limitorque
actuator.
The worm and wormshaft are supported by two rotating spring packs. As torque is generated by the
actuator, the worm moves axially against one of the spring packs. Each pack is precalibrated and hence
a finite compression represents a finite torque output. Movement of the worm operates the torque
switch, which interrupts the power to the motor. The torque switch is adjustable and can be set to
operate at predetermined torque levels.