Specifications

G19
GE Limitamp
®
Medium Voltage Motor Control
Components
G
Description
The DIE#SP-0330 motor restart control relay is an 11 pin
plug-in relay (socket # CIC#RB11) that provides automatic
restart of a motor following a momentary interruption of
control power. Since the control power is derived from the
power bus, the relay may be used to monitor interruptions
on the power system.
The relay consists of two adjustable timing functions. The first
timer, called the UV timer (adjustable from 0.2 - 6 seconds)
limits the time the control power may be interrupted for an
auto-restart to occur. If the interruption lasts longer than the
timer setting, the motor will not restart on restoration of power
and a manual restart will be required. If power is restored
before the timer times out, then the motor will restart auto-
matically after a second timer delay.
The second timer, called the restart delay timer (adjustable
from 0.2 - 60 seconds) is a delay on restart following
restoration of control power. This second timer can be set to
allow time for rotor currents to decay following an interruption
of power, so that a motor (particularly a synchronous motor)
is not re-energized out of phase with field or squirrel-cage
current present. Motor auto-restart relays in a group of motor
controllers can be independently set to allow for a staggered
restart of motors over a period of time to minimize impact to
the power system on restoration of power.
The relay also has the feature of distinguishing between
control power interruptions and “STOP” pushbutton operations.
Following a “STOP” pushbutton operation, the relay is locked-
open and inadvertent spontaneous motor starts will not occur
due to rapid momentary “STOP” pushbutton operations or
control power disturbances.
The following diagram is a simplified elementary showing
relay wiring:
Please note the following restrictions:
• Overload contact must be normally closed, so Multilin
relays must have trip contact set “non-failsafe”.
• Place no contacts of any kind between UVAR (6) and MX
relay coil.
• Use this relay only when momentary start and stop push-
buttons are used. Do not use with maintained contact
start- stop schemes.
Nomenclature
UVAR - TIME DELAY UNDERVOLTAGE MO
TOR AUTO-RESTART RELAY
M - MAIN MOTOR CONTACTOR
MX - CONTROL RELAY
OL - OVERLOAD OR OTHER PROTECTIVE RELAY
PB - MANUAL PUSHBUTTON
MX
UV Delay: 2 Secs
Restart Timer Delay: 1 Sec
120VAC Control
OL Stop PB
Start PB
MX
(2)(8) PWR
UVAR
(
6)(5)
M
M
120VAC Control
Motor Auto-Restart Relay