Table of Contents
Advertisement
17.2
TRIP CIRCUIT SUPERVISION FOR M-FAMILY RELAYS
M Family relays (MIF must be option 2 to include I/O & Logic configurability) can be used to monitor Trip circuit
integrity. The circuit is basically a Voltage Monitor connected to contact 52a. The circuit is continuously monitoring the
voltage level. The circuit below is designed to monitor the complete trip circuit. It includes the tripping coil of the
breaker and the trip circuit, the wiring between the relays, and the circuit breaker.
An alarm can be issued when the circuit is open. The figure below shows the typical wiring diagram that will provide
trip circuit monitoring while the circuit breaker is closed.
For monitoring the trip circuit while the breaker is open and when it is closed, a resistor must be added in parallel to
the 52a contact, as shown below:
+Vdc
TRIP
Breaker
Auxiliary
Contact (52a)
R
TRIP COIL
17-4
APPLICATION NOTES
+Vdc
TRIP
Breaker
Auxiliary
Contact (52a)
TRIP COIL
A5
A6
A8
A9
A10
MIF Digital Feeder Protection
A5
A6
A8
INP#1
A9
INP#2
A10
COM
TRIP
INP#1
INP#2
COM
TRIP
Value of resistor R
Supply
Ohms
48 Vdc
10 K
125 Vdc
25 K
250 Vdc
50 K
Watts
2
5
5
GEK-106273L
Advertisement
Table of Contents
