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Wye-delta Open Transition Starter - GE MM300 Instruction Manual

Motor management system low voltage motor protection and control.
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Wye-delta open
transition starter
Figure 5-7: Typical starter timing for two-speed starter
Motor current
Contactor A relay
Contactor B relay
The following additional setpoints are available for the two-speed starter.
High Speed FLA
Range: 0.5 to 1000.0 amps in steps of 0.1
Default: OFF
This setpoints specifies the maximum continuous phase current when running in high
High Speed Motor Rating
Range: 0.3 to 1100.0 kW in steps of 0.1 or OFF
Default: OFF
This setpoint specifies the high-speed motor rating for two-speed starters in kWs on the
line. This setpoint is for reference only and does not affect operation of the MM300.
High Speed Start Block
Range: Enabled, Disabled
Default: Enabled
When this setpoint is programmed as "Disabled", the relay allows the motor to be
started directly to high speed. When programmed as "Enabled", the motor must be
running in low-speed before switching to high-speed.
Transfer Time
Range: 0 to 125 seconds in steps of 1
Default: 1 second
This setpoint represents the time between running at high speed and starting at low
speed for the two speed starter.
The wye-delta open transition starter is a reduced voltage starter.
When a start A control is received, the pre-contactor relay (if any) is picked up for the set
. When the pre-contactor timer times out, the contactor A relay picks
Pre-Contactor Time
up and seals-in, picking up the 1S contactor, which connects the motor in wye
configuration. The 1S contactor in turn picks up the 1M contactor, which connects the
motor to the supply. The motor is now starting at 58% voltage. When the transfer time
timer expires, the contactor A relay is de-energized, contactor 1S drops out, opening the
wye and disconnecting the motor from the supply. When the contactor 1S status off is
received, the contactor B relay picks up and seals-in, picking up the 2M contactor, which
connects the motor in delta configuration. The 2M contactor in turn picks up the 1M
contactor, which connects the motor to the supply. The motor is now running at full
voltage. When a stop control is received, the contactor A and B relays are dropped out,
contactor 1S and 2M drop out, contactor 1M drops out, and the motor stops.
P - Pre-contactor time setting
T - Transfer time setting


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