GE MM3, Instruction Manual, Page: 29 / 230

CHAPTER 2: INSTALLATION STARTER TYPES
MM3 MOTOR MANAGER 3 – INSTRUCTION MANUAL 2–11
2.4.3 Two-speed
Starter
When the low speed button is pressed, the CR coil will pick up and seal itself in. The L
contactor is then picked up and the motor starts in low speed. When the high speed button
is pressed, the L contactor drops out and the H contactor picks up and seals itself in; timing
relay TR is also picked up. If the low speed button is pressed, the TR relay will prevent the
motor from going to low speed until it times out and the motor has had time to slow down.
Figure 2-8: Elementary Two-speed Magnetic Starter
To program the MM3 Motor Manager 3 for two-speed starter, set:
S1 CONFIGURATION ÖØ STARTER Ö STARTER TYPE
: TWO-SPEED
S1 CONFIGURATION
ÖØ
STARTER
ÖØ
TRANSFER TIME
: 1 to 125 sec.
S1 CONFIGURATION ÖØ STARTER ÖØ HIGH SPEED START BLOCK
: ENABLE or DISABLE
The TRANSFER TIME setpoint appears when the STARTER TYPE is “TWO-SPEED”. This delay
may be required when the motor is switched from high-speed (contactor B) directly to low-
speed (contactor A). The delay starts when contactor B drops out.
The HIGH SPEED START BLOCK appears when the STARTER TYPE is “TWO-SPEED”. When
set to “DISABLED”, the MM3 Motor Manager 3 allows the motor to be started directly to
high speed. When set to “ENABLED”, the motor must be started in low-speed before
switching to high-speed.
Start low speed sequence:
1. Start A command received by the MM3 Motor Manager 3 (serial, switch input
or faceplate).
2. Close and maintain contactor A relay – the motor is now in low speed.
Start directly to high speed (motor stopped, HIGH SPEED START BLOCK not enabled):
1. Start B command received by the MM3 Motor Manager 3 (serial, switch input
or faceplate).
2. Close and maintain contactor B relay – the motor is now in high speed.