GE Power Management 750/760 Feeder Management Relay 3-
13
3 INSTALLATION 3.2 TYPICAL WIRING
3
3.2.11 TRIP / CLOSE COIL SUPERVISION
Supervision of a breaker trip coil requires the relay supervision circuit to be wired in parallel with the 1 TRIP
contact. Likewise, supervision of the close coil requires the supervision circuit to be wired in parallel with the 2
CLOSE contact. Each connection places an impedance across the associated contact, which allows a small
trickle current to flow through the related trip and close coil supervision circuitry. For external supply voltages in
the 30 to 250 V DC range, this current draw will be between 2 to 5 mA. If either the trip or close coil supervision
circuitry ceases to detect this trickle current, the appropriate failure will be declared by the relay.
When the
BREAKER STATE BYPASS
setpoints are disabled, the logic only allows a trip circuit to be monitored
when the breaker is closed and a close circuit to be monitored when the breaker is open.
Circuit breakers equipped with standard control circuits have a 52a auxiliary contact which only allows tripping
of the breaker when it is closed. In this breaker state, the 52a contact is closed and a trickle current will flow
through the trip circuitry. When the breaker is open, the 52a auxiliary contact is also open and no trickle current
will flow. When the breaker position monitoring inputs detect an open breaker, the trip coil supervision monitor-
ing function will be disabled.
Figure 3–16: TRIP / CLOSE COIL SUPERVISION CONNECTION
In a similar manner, the 52b auxiliary contact only allows closing of the breaker when it is open. In this breaker
state, the 52b contact is shorted and a trickle current will flow through the breaker’s close circuitry. When the
breaker is closed, the 52b auxiliary contact is open and no trickle current will flow. When the breaker position
monitoring inputs detect a closed breaker, the close coil supervision monitoring function will be disabled.
To Next Page
Loading...
Need help?
General
