Close Coil - GE 339 Instruction Manual

M3 BREAKER MAINTENANCE

Close coil

NOTE:
NOTE
7–10
Close coil monitoring is performed by a built-in voltage monitor on the Form A output relay:
#2 Close. The voltage monitor is connected across the Form A contact, and effectively the
relay detects healthy current through the circuit. To do that, an external jumper should be
made between terminals "B4", and "B5" for Close coil monitoring.
As long as the current through the Voltage Monitor is above the threshold of the trickle
currents (see Technical Specification for Form A output relays), the circuit integrity for the
Close coil is effectively normal. If the Close coil circuit gets disconnected, or if in general a
high resistance is detected in the circuitry, a Relay 2 Coil Monitor Alarm will be set and the
"ALARM" and "MAINTENANCE" LEDs will be on.
Example 1: The figure below shows the connection of the breaker close coil to the relay's
close output relay for voltage monitoring of the close circuit.
To monitor the close coil circuit integrity, use the relay terminals "B4" and "A4" to connect
the Close coil, and provide a jumper between terminals "B4" and "B5" (voltage monitor).
Figure 6: Close Coil circuit with voltage monitoring
Output Relay 2 (CLOSE)
Example 2: Some applications require that the Close Coil be monitored continuously,
regardless of the breaker position (open or closed). This can be achieved by connecting a
suitable resistor (see the table) across breaker auxiliary contact 52b in the Close circuit.
With such connections, the trickle current will be maintained by the resistor when the
breaker is closed. For these applications the setting for "BYPASS BKR STATUS" should be set
to ENABLED.
B4
A4
V
B5
52b
contact
Close
896785.cdr
339 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 7: MAINTENANCE
DC +
External
jumper
Coil
DC -