GE Power Management
469 Motor Management Relay
4-47
4 SETPOINT PROGRAMMING
4.7 S6 CURRENT ELEMENTS
4
4.7.2 OVERLOAD ALARM
If enabled as
"Latched"
or
"Unlatched"
, the Overload Alarm functions as follows. After a motor start, when the
equivalent motor heating current exceeds the
OVERLOAD PICKUP LEVEL
, an alarm will occur. If programmed as
Unlatched
, the overload alarm resets itself when the motor is no longer in overload. If programmed as
"Latched"
,
the
key must be pressed to reset the alarm once the overload condition is gone. Event recording for all
alarm features is optional.
For example, it may be desirable to have an unlatched alarm connected to a PLC that is controlling the load on
a motor.
4.7.3 MECHANICAL JAM
If turned On, the Mechanical Jam element function as follows. After a motor start, a Trip occurs once the mag-
nitude of Ia, Ib, or Ic exceeds the Pickup Level × FLA for a period of time specified by the
MECHANICAL JAM
DELAY
setpoint. This feature may be used to indicate a stall condition when running. Not only does it protect the
motor by taking it off-line quicker than the thermal model (overload curve), it may also prevent or limit damage
to the driven equipment if motor starting torque persists on jammed or broken equipment.
The
MECHANICAL JAM PICKUP
level should be set higher than motor loading during normal operation, but lower
than the motor stall level. Normally the delay is set to the minimum time delay or set so that no nuisance trips
occur due to momentary load fluctuations.
y
OVERLOAD ALARM
y
[ENTER] for more
OVERLOAD
ALARM: Off
Range: Off, Latched, Unlatched
ASSIGN ALARM RELAYS:
Alarm
Range:
Alarm, Auxiliary2, Auxiliary3, Alarm & Aux2,
Alarm & Aux3, Aux2 & Aux3, Alarm & Aux2 & Aux3
OVERLOAD ALARM
DELAY: 0.1 s
Range: 0.1 to 60 sec., step: 0.1
OVERLOAD ALARM
EVENTS: Off
Range: On, Off
y
MECHANICAL JAM
y
[ENTER] for more
MECHANICAL JAM
TRIP: Off
Range: Off, Latched, Unlatched
ASSIGN TRIP RELAYS:
Trip
Range:
Trip, Trip & Auxiliary2, Trip & Aux2 & Aux3;
Trip & Auxiliary3
MECHANICAL JAM
PICKUP: 1.50 x FLA
Range: 1.01 to 3.00 x FLA, step 0.01
MECHANICAL JAM
DELAY: 1 s
Range: 1 to 30 sec., step 1
ENTER
ESCAPE
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ð
MESSAGE
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RESET
ENTER
ESCAPE
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ð
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ESCAPE