SERIES 71, 72, AND 76 MODUTROL IV™ MOTORS
11
63-2640—07
Fig. 12. Auxiliary switch adjustment.
OPERATION AND CHECKOUT
Operation
The internal shaft position feedback potentiometer in
conjunction with the actuator microprocessor and modulating
input circuit form a control loop. When the external controller’s
output remains at a fixed amplitude the actuator’s shaft
position is held at a position proportional to that input
amplitude. When the value of the external controllers output
changes the actuator responds by initiating movement of the
motor to proportionately compensate for the change in input
amplitude. When the motor reaches the control loop balance
point the system is again in a static state and the actuator
holds position until the next change of input from the external
controller.
M7685 motor also have a minimum position feature. An
external 130 ohm potentiometer wired to terminals 3 and 4
establishes a position beyond which the control input cannot
close the motor. If power to the T1-T2 is interrupted the M7685
motor will spring close.
Checkout
After installation and linkage adjustment, operate the motor
through the controller. Make sure that:
• The motor properly operates the damper or valve.
• The motor responds properly as the input is varied.
• The auxiliary switch, if used, operates at the desired point of
motor rotation.
Inspect the motor, linkage, and valve or damper to see that all
mechanical connections are correct and secure.
In damper installations, the pushrod should not extend more
than a few inches past the ball joints. Check to see that there is
adequate clearance for the linkage to move through its stroke
without binding or striking other objects.
See controller or system instructions for additional checkout
procedures.
Motor Operation Checkout
For motors with F, + and - terminals:
To close the motor, open ter, -, and F.
To open the motor connect terminal F to positive (+) or
negative (-).
NOTE: DO NOT SHORT + to -
M7164A1017 and M7164G1030 do not have + or –
terminals, and operate as follows:
The motor closes if it does not receive an input to F.
To open the motor, short F to C.
M7685A1025 is a normally open motor, and operates as
follows:
To close the motor, short 3 to 4 or short 3 to C.
The motor opens if it does not have an input to 3.
RIGHT/INNER
AUXILIARY
SWITCH
FAST RISE
PORTION
(APPROX.
1 DIFF.)
SLOW RISE
PORTION
(APPROX.
10 DIFF.)
INNER
AUXILIARY
CAM
(BLUE)
NOTE: CAMS ARE OFFSET
VERTICALLY TO PROVIDE
BETTER VIEW OF BACK CAM.
FAST RISE
PORTION
(APPROX.
1 DIFF.)
SLOW RISE
PORTION
(APPROX.
10 DIFF.)
MOTOR
OPEN
MOTOR
CLOSE
POWER
END
OUTER
AUXILIARY
CAM
(RED)
LEFT/OUTER
AUXILIARY
SWITCH
M17101
POWER END
OF MOTOR
OUTER AUXILIARY
CAM (RED)
INNER AUXILIARY
CAM (BLUE)
RIGHT/INNER
AUXILIARY SWITCH
LEFT/OUTER
AUXILIARY
SWITCH
MOVE SCREWDRIVER AT
TOP ONLY TO ADJUST CAM.
1/8 INCH
STRAIGHT-BLADE
SCREWDRIVER
