Mm3 Sequences - GE MM3 Instruction Manual

9.2 FV REVERSING STARTER 9 STARTER TYPES

9.2.2 MM3 SEQUENCES

START:
1. Start A command received by the MM3 (serial, switch input or faceplate).
2. Close and maintain Contactor A output relay – the motor is now across the line in the forward direction.
STOP/TRIP:
1. Stop command received by the MM3 or a trip occurs.
2. Open the currently closed Contactor output relay – the motor stops.
REVERSE (if the motor is running in the forward direction):
1. Start B command is received by the MM3 (serial, switch input or faceplate).
2. Open Contactor A relay – the motor is now off line
3. Wait the required transfer time.
4. Close and maintain Contactor B output relay – the motor is now across the line in the reverse direction.
9.2.3 NOTES
All output relays de-energize when the MM3 power is interrupted, causing them to open and stop the motor.
The MM3 can only be wired for fail-safe operation.
If used, the VT input must have a separate PT so that the current and voltage inputs remain in phase regard-
less of which direction the motor is running. See Figure 9–4: FV REVERSING STARTER on page 9–5.
If feedback is not received from either the F or the R contactor to Contactor Status N.O. inputs within one sec-
ond of closing Contactor A or B output relays, an OPEN CONTROL CIRCUIT alarm will occur. This will cause
the currently closed relay to open.
If feedback remains at the Contactor (A or B) Status N.O. input more than one second after opening Contactor
A or B output relays, a WELDED CONTACTOR alarm will occur.
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9-4 MM3 Motor Manager 3 GE Power Management