GE 469 User Manual

CHAPTER 5: SETTINGS
469 MOTOR MANAGEMENT RELAY – INSTRUCTION MANUAL 5–59
5.7 S6 Current Elements
5.7.1 Short Circuit Trip
PATH: SETTINGS ZV S6 CURRENT ELEM. Z SHORT CIRCUIT TRIP
Care must be taken when turning On this feature. If the interrupting device (contactor
or circuit breaker) is not rated to break the fault current, this feature should be
disabled. Alternatively, this feature may be assigned to an auxiliary relay and
connected such that it trips an upstream device that is capable of breaking the fault
current.
If turned on, the Short Circuit element functions as follows.
A trip occurs once the magnitude of either Ia, Ib, or Ic exceeds the Pickup Level × Phase CT
Primary for the time specified by
INTENTIONAL S/C TRIP DELAY. A backup trip feature may
also be enabled. The
SHORT CIRCUIT TRIP BACKUP DELAY should be greater than the
INTENTIONAL S/C TRIP DELAY plus the breaker clearing time. If the SHORT CIRCUIT TRIP
BACKUP is “On” and a Short Circuit trip has initiated, a second trip occurs if the motor phase
current persists for a time exceeding the
SHORT CIRCUIT TRIP BACKUP DELAY. It is intended
that this second trip be assigned to 2 Auxiliary or 3 Auxiliary which would be dedicated as
an upstream breaker trip relay. Whenever the output relay assigned to backup trip
operates, it will remain latched regardless of how the trip relay is configured for the Short
Circuit Trip element.
Various situations (e.g. charging a long line to the motor or power factor correction
capacitors) may cause transient inrush currents during motor starting that may exceed
the
SHORT CIRCUIT TRIP PICKUP level for a very short period of time. The INTENTIONAL S/C
TRIP DELAY is adjustable in 10 ms increments. This delay can be fine tuned to an
application so it still responds very fast but rides through normal operational disturbances.
Normally, the
INTENTIONAL S/C TRIP DELAY is set as quick as possible, 0 ms. This time may

SHORT [
SHORT CIRCUIT
TRIP: Off
Range: Off, Latched, Unlatched
MESSAGE
SHORT CIRCUIT
TRIP
Range: On, Off
MESSAGE
ASSIGN TRIP
RELAYS:
Range: Tri, Trip & Aux 2, Trip & Aux2 &
Aux3, Trip & Aux3, Aux2, Aux2
& Aux3, Aux3
MESSAGE
SHORT CIRCUIT
TRIP
Range: 2.0 to 20.0 x CT in steps of 0.1
MESSAGE
INTENTIONAL S/C
TRIP
Range: 0 to 1000 ms in steps of 10
MESSAGE
SHORT CIRCUIT
TRIP
Range: On, Off
MESSAGE
ASSIGN BACKUP
RELAYS:
Range: Auxiliary2, Aux2 & Aux3,
Auxiliary3
MESSAGE
SHORT CIRCUIT
TRIP
Range: 10 to 2000 ms in steps of 10

GE 469 Specifications

General

Brand	GE
Model	469
Category	Relays
Language	English