5–60
469 MOTOR MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS
5.7
S6 Current Elements
5.7.1
Short Circuit Trip
PATH: SETTINGS
S6 CURRENT ELEM.
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 [
]
CIRCUIT TRIP
SHORT CIRCUIT
TRIP: Off
Range: Off, Latched, Unlatched
MESSAGE
SHORT CIRCUIT TRIP
OVERREACH FILTER: Off
Range: On, Off
MESSAGE
ASSIGN TRIP RELAYS:
Trip
Range: Trip, Trip & Aux 2, Trip & Aux2 &
Aux3, Trip & Aux3, Aux2, Aux2 &
Aux3, Aux3
MESSAGE
SHORT CIRCUIT TRIP
PICKUP: 10.0 x CT
Range: 2.0 to 20.0 x CT in steps of 0.1
MESSAGE
INTENTIONAL S/C TRIP
DELAY: 0 ms
Range: 0 to 1000 ms in steps of 10
MESSAGE
SHORT CIRCUIT TRIP
BACKUP: Off
Range: On, Off
MESSAGE
ASSIGN BACKUP
RELAYS: Auxiliary2
Range: Auxiliary2, Aux2 & Aux3,
Auxiliary3
MESSAGE
SHORT CIRCUIT TRIP
BACKUP DELAY: 200 ms
Range: 10 to 2000 ms in steps of 10
Summary of Contents for Masoneilan 469 Series
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Page 92: ...3 28 469 MOTOR MANAGEMENT RELAY INSTRUCTION MANUAL CHAPTER 3 INSTALLATION ...
Page 256: ...5 112 469 MOTOR MANAGEMENT RELAY INSTRUCTION MANUAL CHAPTER 5 SETTINGS ...
Page 298: ...6 42 469 MOTOR MANAGEMENT RELAY INSTRUCTION MANUAL CHAPTER 6 ACTUAL VALUES ...
Page 321: ...CHAPTER 8 APPENDIX 469 MOTOR MANAGEMENT RELAY INSTRUCTION MANUAL 8 9 808712A1 CDR ...
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