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R7195A,B MOTOR POSITIONER
R7195
SUPPLY
OPERATION
Operating Principles
See Fig. 8 and 9.
When the motor positioner is connected to a reversing control
motor, proportioning controller, and power supply (as specified
in the application), the unit will operate as follows:
SENSOR
INPUT FROM
CONTROLLER
POWER SUPPLY
63-2582
R7195A,B
MOTOR POSITIONER
L2
L1
G
2
GROUND
NEUTRAL
HOT
120 VAC
L1
24 VAC
L2
2
3
1
M944B, E
MODUTROL
MOTORS
Y
T
G
Fig. 7. Connections to M944B,E Modutrol® Motors.
FEEDBACK
POTENTIOMETER
BALANCING BRIDGE CIRCUIT
(COMPARES INPUT TO
FEEDBACK POTENTIOMETER)
ZERO CROSSING CIRCUITS (220/240 VAC)
OPTO ISOLATORS (120 VAC)
(PROVIDE RFI PROTECTION;
ALSO DRIVES TRIACS)
Fig. 8. Block diagram.
6
5
6
4
3
B
W
1
R
–
+
TERMINALS TO
4-20 mA INPUT
The controller output signal is transmitted to the balancing
bridge portion of the motor positioner. The balancing bridge
will compare the controller output to the feedback
potentiometer voltage. This compared voltage is referred to as
the error signal voltage. The balancing bridge circuit will
amplify the error signal, causing a Triac switch to fire. This will
energize a motor winding and will re-position the feedback
potentiometer until the error signal is reduced to zero.
MOTOR
WINDINGS
TRIAC SWITCHES
B
W
R
CW
135-OHM
POTENTIOMETER
INPUT
M20792
M20793
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