The Trip circuit of circuit breaker is normally wired through CB auxillary contacts and other interlocks (like spring charging full etc) and then connected to Trip solenoid coil of circuit breaker and control voltage source through fuse links. MRA- Pro-V2 continuously monitors these junction points. In the event of fault (like TC coil is open or short, TC coil supply is less than 40% or CB contact failure) in the trip circuit it immediately triggers the internal timer. After expiration of supervision time delay if the faulty condition persists then it is reported as fault by two output relay operation and CB failed LED indication. This scheme ensures that all trip circuit wiring (tripping route) from trip contact to the trip coil is supervised in either the breaker closed or open condition.
There are two modes of operation as under
a) Auto Mode: In this mode Trip circuit faulty status indication automatically gets reset once Trip circuit becomes healthy.
b) Manual Mode: In this mode Trip circuit faulty status indication will not be reset unless user reset it through a front RESET key through a single press.
To facilitate routine checkup there is a provision for TEST function in MRA- Pro-V2. User can enter into this mode by keeping the RESET key in pressed condition and then providing the auxiliary supply. To bring back to normal operation from this mode user has to switch off and then switch on the auxillary supply of MRA- Pro-V2