Trip/Close Coil Supervision - GE 750 Instruction Manual

750/760 Electrical Installation
Feeder Management Relay
Trip/Close Coil Super-
Supervision of a breaker trip coil requires the relay supervision circuit to be wired in
vision parallel with the Trip contact. Likewise, supervision of the close coil requires the
supervision circuit to be wired in parallel with the 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 setpoint is "Disabled", the logic only allows a trip circuit
BRKR STATE BYPASS
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 monitoring function will be disabled.
FIGURE 3–17: Trip/Close Coil Supervision
GE Multilin
3–12
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