Soft Starter - GE MM300 Instruction Manual

CONFIGURATION SETPOINTS

Soft starter

5–12
Ramp Up Time
Range: 0 to 125 seconds in steps of 1
Default: 1second
This setpoint specifies the time after signalling the inverter starter to ramp up that the
up-to-speed feedback can be delayed without issuing a Drive Start Fail alarm.
Ramp Down Time
Range: 0 to 125 seconds in steps of 1
Default: 1second
This setpoint specifies the time after signalling the inverter starter to ramp down before
the main contactor is opened, cutting power to the starter. If speed feed back is still on
when this time expires, a Drive Stop Fail alarm is issued.
The "Soft Starter" type is used with an external soft starter that ramps the motor speed up
on start and down on stop. Once the motor is ramped up, the soft starter can be bypassed.
When a start A control is received, the pre-contactor (if any) is picked up for the set delay,
then relay1 picks up and seals-in, picking up contactor 1M. This provides power for the Soft
Starter to start up. Relay2 closes after a 1 second delay, and seals in, which signals the soft
starter to ramp up the motor. When a stop control is received, the relay2 drops out, and
the soft starter ramps down. When the ramp down time timer has expired, relay1 is
opened, contactor 1M drops out, cutting power to the soft starter and motor.
Forced starts (for example, external start) operate in the same fashion as other starts, with
the B contactor not calling for the soft starter to ramp until the pre-contactor timer times
out.
If up to speed feedback is not received from the soft starter via the contactor B status
within the setpoint during a start, a Drive Start Failed alarm is generated. If
Ramp Up Time
soft starter speed feedback remains when the
Drive Stop Fail alarm is generated. Neither results in a trip or a stop. The Drive Start Failed
alarm is latched until reset.
The B Open Contactor Control Circuit and B Welded Contactor alarms implemented in the
start/stop control element are defeated when the soft starter is selected.
If the soft starter does not provide an up to speed feedback signal, the contactor B relay
contact or an auxiliary contact of the B contactor should be connected to the up to speed
feedback contact input to suppress spurious Drive Failed To Start alarms.
The Undervoltage Autorestart feature is disabled for the Soft Starter.
The following figure illustrates typical starter timing beginning from the stopped state.
Figure 5-10: Typical starter timing for the soft starter
Motor current
Contactor A relay
Contactor B relay
Pre-contactor
P
Starting
Running
Stopping
The following additional setpoints are available for the soft starter.
Ramp Down Time
1s
P = Pre-contactor time setting
R = Ramp Down time setting
MM300 MOTOR MANAGEMENT SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETPOINTS
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853721A3.CDR