Breaker Trip Coil monitor 1

[JetsKnicksYankees]

We have a high voltage breaker with 2 trip coil per phase. We want to monitor the status of this trip coil and we installed TIR from USI in series with these trip coils. The TIRs are activated by sensing the presence of current in the trip coil.

Question is whether the series connected relay would be adequate to monitor the status of the trip coil or not. Would there be a condition when TIR won't adequately monitor the status of the trip coil? E.g. if TIR is tripped out already and breaker is in trip position and trip signal is sent to Trip coil.

 

[davidbeach]

Ideally you want something that will trickle current through the trip coil all the time. We use a relay input in parallel with the trip output. The trip coil is a low enough resistance that the input will pickup when there is continuity through the trip circuit. The input has a high enough resistance that the current through the trip coil will be a few milliamps at most, less than the old incandescent red light.

 

[mgtrp]

Just to confirm - are you trying to determine whether the trip coil is healthy, which is what davidbeach describes above, or something similar to this, which monitors whether or not a the circuit breaker is tripped? Your title says one, but your post seems to say the other.

 

[GTstartup]

"Question is whether the series connected relay would be adequate to monitor the status of the trip coil or not. Would there be a condition when TIR won't adequately monitor the status of the trip coil? E.g. if TIR is tripped out already and breaker is in trip position and trip signal is sent to Trip coil"

If the breaker is tripped already you can't monitor the current to the trip coil because the trip coil is disconnected by the position contacts of the breaker (anti pumping).

 

[ScottyUK]

Actually it's quite simple to use a pair of auxiliary contacts to ensure that the coil is monitored in both states. At least you can if the TCS relay uses the conventional method of bleeding a small current through a resistor and through the tripping coil; if your relay uses some different method then maybe that wouldn't work.