Control Power - GE 750 Instruction Manual

CHAPTER 3: INSTALLATION
3.2.8 Trip/Close Coil
Supervision
750 FEEDER MANAGEMENT RELAY – INSTRUCTION MANUAL
Supervision of a breaker trip coil requires the relay supervision circuit to be wired in 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
BRKR STATE BYPASS
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 3–14: Control Power Connection
setpoint is "Disabled", the logic only allows a trip circuit to be
ELECTRICAL INSTALLATION
996618AL.CDR
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