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Fig. 10—Auxiliary switch and adjustable cams.
OPERATION
The motor feedback potentiometer and control current
input circuit form a bridge circuit. As long as the final
control element remains at the position proportional to the
input current from the controller, the circuit is balanced,
and the motor does not run. When the value of the con-
trolled medium changes, the current from the controller
changes, and unbalance is amplified to energize the Triac
switching to run the motor in the proper direction to correct
the change in the temperature or the pressure. The motor
turns the feedback potentiometer to rebalance the circuit
and stop the motor.
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.
M7261,M7272,M7274,M7281,M7282,M7284,M7285,M7286,M7294
SETTINGS AND ADJUSTMENTS • OPERATION AND CHECKOUT
MOVE SCREWDRIVER AT TOP ONLY TO ADJUST CAM
1/8 IN. STRAIGHT-BLADE
SCREWDRIVER
SLOW RISE
PORTION
(APPROX.
10° DIFF.)
INNER
AUXILIARY
CAM
(BLUE)
LEFT/OUTER
AUXILIARY
SWITCH
OUTER
FAST RISE
AUXILIARY
PORTION
CAM
(APPROX.
(RED)
1° DIFF.)
MOTOR OPEN
POWER END
NOTE: CAMS ARE OFFSET VERTICALLY TO
PROVIDE BETTER VIEW OF BACK CAM.
Operation and Checkout
• The auxiliary switch, if used, operates at the desired
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 ob-
jects. See controller or system instructions for addi-
tional checkout procedures.
Motor Operation Checkout
Check motor operation as follows:
1. To close the motor, open terminals +, -, and F.
2. To open the motor, connect terminal F to the negative
(-) motor terminal.
11
RIGHT/INNER
AUXILIARY
SWITCH
FAST RISE
PORTION
(APPROX.
1° DIFF.)
SLOW RISE
PORTION
(APPROX.
10° DIFF.)
MOTOR CLOSED
M5775
point of motor rotation.
63-2202—3
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