Description - GE MM3 Instruction Manual

9 STARTER TYPES
9.7 AUTOTRANSFORMER OPEN TRANSITION STARTER
This starter type is a reduced voltage starter. When the start button is pressed, timing relay TR is picked up
and seals itself in. The 1S coil is also picked up which then picks up the 2S coil. The 1S contacts configure the
autotransformer windings into an open delta for two winding or wye for three winding autotransformers. The 2S
contacts bring the autotransformer on line providing reduced voltage to the motor. When the timing relay TR
times out 1S and 2S drop out and then contactor coil R picks up and full voltage is applied to the motor.
Figure 9–15: ELEMENTARY AUTOTRANSFORMER OPEN TRANSITION MAGNETIC STARTER
To program the MM3 for autotransformer open transition starter, set:
S1 CONFIGURATION\STARTER\STARTER TYPE: AUTOTRANS OPN TRANS
S1 CONFIGURATION\STARTER\CHANGE OVER TIME: 1 to 125 sec.
S1 CONFIGURATION\STARTER\CONTACTOR SEQUENCE: 1S-2S, 2S-1S
S1 CONFIGURATION\STARTER\STARTS PER HOUR: 1 to 40
S3 PROCESS\PROGRAMMABLE INPUTS\INTERLOCK INPUT 10: AUTOTRANS 2S CONTACT
S4 CONTROL\AUX 1 RELAY CONFIG\AUX RELAY 1 FUNCTION: AUTOTRANSFORMER 2S
The CONTACTOR SEQUENCE setpoint appears when STARTER TYPE is selected as AUTOTRANS OPN TRANS. The 1S-
2S value closes the 1S contactor ahead of the 2S contactor as per some manufacturer's wiring practices. The
2S-1S value closes the 2S contactor ahead of the 1S contactor, another common wiring practice.
The CHANGE OVER TIME setpoint appears when STARTER TYPE is selected as AUTOTRANS OPN TRANS. This repre-
sents the time delay from the closure of Contactor A until the opening of Contactor A.
The STARTS PER HOUR setpoint appears only when STARTER TYPE is selected as AUTOTRANS OPN TRANS. This
setpoint limits the number of starts per hour to prevent overheating of the autotransformer windings.
GE Power Management
9.7 AUTOTRANSFORMER OPEN TRANSITION STARTER
MM3 Motor Manager 3

9.7.1 DESCRIPTION

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