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9.12 DUTY/STANDBY STARTER
9.12 DUTY/STANDBY STARTER
This starter type is a full voltage starter and allows a single MM3 to control two identical motors. This starter
type has two modes, manual and automatic. In manual mode a switch input determines which of the two
motors is available for operation. In automatic mode the MM3 selects which motor should run based on the
number of starts performed. An even number of starts will start motor A and an odd number will start motor B.
To program the MM3 for duty/standby starter, set:
S1 CONFIGURATION\STARTER\STARTER TYPE: DUTY/STANDBY
S3 PROCESS\PROGRAMMABLE INPUTS\INTERLOCK INPUT 1: DUTY SELECT MAN/AUTO
S3 PROCESS\PROGRAMMABLE INPUTS\INTERLOCK INPUT 2: MOTOR SELECTOR A/B
START (manual) sequence:
1. Duty Select MAN/AUTO open.
2. Motor Selector A/B open.
3. Start A command received by the MM3.
4. Close Contactor A relay – Motor A is now running.
5. Stop command.
6. Motor Selector A/B closed.
7. Start A command received by the MM3.
8. Close Contactor B relay – Motor B is now running.
START (auto) sequence:
1. Duty Select MAN/AUTO closed.
2. Motor Selector A/B has no effect.
3. Start A command received by the MM3 (number of starts = 0, even).
4. Close Contactor A relay – Motor A is now running.
5. Stop command.
6. Start A command received by the MM3 (number of starts = 1, odd).
7. Close Contactor B relay – Motor B is now running.
STOP/TRIP sequence:
1. Stop command received by the MM3 or a trip occurs.
2. Open the active contactor A or B.
When the power to the MM3 is interrupted, all output relays on the MM3 will de-energize causing them to open
and stop the motor. The MM3 can only be wired for fail-safe operation.
If feedback is not received by the Contactor A Status N.O. or Contactor B Status N.O. inputs within one second
of closing the corresponding output relay, an OPEN CONTROL CIRCUIT alarm will occur. This will open the
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active output relay which will stop the motor.
If feedback remains at Contactor A Status N.O. or Contactor B Status N.O. inputs for more than one second
after opening the corresponding output relay, a WELDED CONTACTOR alarm will occur.
The Start A input and key are used to start motors A and B. The Start B input and faceplate key have no effect.
Serial Control starts override the mode of operation of the Duty/Standby starter. For example a serial start B
command will always start motor B and a serial start A will always start motor A. This is true for AUTO START
A and AUTO START B programmable interlock functions as well.
9-34
MM3 Motor Manager 3
9 STARTER TYPES
9.12.1 DESCRIPTION
9.12.2 MM3 SEQUENCES
GE Power Management
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