Mm3 Sequence - GE MM3 Instruction Manual

9.11 WYE-DELTA CLOSED TRANSITION STARTER
START sequence:
1. Start command received by the MM3.
2. Close Contactor A relay – this causes the 1S wye contactor to pick up which connects the motor windings
in the wye configuration.
3. Wait approximately 20 ms.
4. Close AUX Relay 1 – this causes the 1M main contactor to pick up which starts the motor.
5. Maintain 1S and 1M contactors until CHANGE OVER CURRENT or CHANGE OVER TIME initiates a transition from
wye to delta. See CHANGE OVER CURRENT and CHANGE OVER TIME descriptions above for more detail.
6. Close Contactor B relay – this causes the 2S resistor contactor to pick up which connects the resistors
across the line.
7. Wait approximately 20 ms.
8. Open Contactor A output relay. This causes the 1S wye contactor to drop out. The normally closed auxil-
iary contacts on the 1S wye contactor pick up the 2M delta contactor which connects the motor in the delta
configuration. The normally closed auxiliary contacts on the 2M contactor drop out the 2S resistor contac-
tor.
STOP/TRIP sequence:
1. Stop command received by the MM3 or a trip occurs.
2. Open 1M and 2M contactors.
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., Contactor B Status N.O. or the WYE DELTA 1M
CONTACT inputs within one second of closing the corresponding output relay, an OPEN CONTROL CIRCUIT
alarm will occur. This will open all three output relays which will stop the motor.
If feedback remains at the programmable switch input that has been configured to WYE DELTA 2S CONTACT
for more than one second, a WELDED CONTACTOR alarm will occur. This will open all three output relays
which will stop the motor. This will prevent the resistors from burning out if the 2S contactor does not open after
switching to the delta configuration.
If feedback remains at Contactor A Status N.O., Contactor B Status N.O. or WYE DELTA 1M CONTACT inputs
for more than one second after opening the corresponding output relay, a WELDED CONTACTOR alarm will
occur.
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9-32 MM3 Motor Manager 3
9 STARTER TYPES

9.11.2 MM3 SEQUENCE

GE Power Management