Flowserve AF-17 Electronic Positioner - Manual (Page 26)

26 AF-17 Electronic Positioner: Installation, Operation and Maintenance WCAIM2031
Flow Control Division
Worcester Controls
Check Action Notes and Cautions
8.3.10 Check temperature of motor(s). Allow the motor(s) to cool so that Duty cycle is specified at an
Each AC motor has a thermal the thermal switches can reset. ambient temperature of 70°F, 60 Hz.
cutout switch built in that opens at Normally the thermal switches will
about 210°F (winding temperature). not open unless the motor's rated
If the thermal cutout in one motor duty cycle is exceeded and/or the
has opened, the other motor by ambient temperature is very high.
itself may not be strong enough to Correct the problem.
move the valve (20-2375 sizes).
8.3.11 Check the operating torque of the If operating torque of valve exceeds If the actuator is removed from a
valve. If necessary, remove the the specified torque for the seats three-piece valve that requires the
actuator from the valve. Measure used and the DP across the valve, body bolts to also be removed, the
valve torque with an accurate determine cause and correct. If valve body bolts must be retorqued to
torque wrench. Check torque under torque falls within normal range, it specification before checking valve
actual operating conditions if possible. is possible that the actuator is torque. See Valve IOM.
undersized.
8.3.12 Check ambient temperature. Actuator duty cycles are specified Higher ambient derates duty cycle.
at an ambient temperature of 70°F.
8.3.13 Check to see that mechanical Replace defective mechanical brake. All 2" CPT valves with positioner
brake is operating correctly. If one was never installed, order a boards in actuator must have
kit and install it in actuator. mechanical brake installed to prevent
oscillation.
8.3.14 Check to see if actuator can move If motor(s) cannot start, go to
a high torque valve from a stop next larger size actuator.
under load when moving in the
same direction as last command
(mechanical brake does not allow
motor(s) to unwind).
8.3.15 Check to see which direction of Replace circuit board.
travel causes problem. If actuator is
coming off open limit switch
(traveling CW) when it slows down
or stops, then either Q1 or U1 is bad.
If actuator is coming off closed limit
switch (traveling CCW), then either
Q2 or U2 is bad. (AC boards only)