Circuit Breaker Wear Monitoring

Simple. RTFM. If the [F]M isn't available, then

the equipment manufacturer and get a replacement.

some of the vacuum contacts may have the warning alarm contacts and some of them they have a marked dot indicator when the vacuum contacts wear out the dots move beyond the tolerance and that is the indication for contact wear or vacuum leak.

By most of manufacturers it is not recommended to do a high pot test, check the manual. If you absolutely want to do the test you can perform the vacuum integrity test using a high pot

•Testing the integrity of the vacuum bottle:- Low resistance readings should be taken across each bottle in the closed position and compared to the manufacturer's limits. If not available, use comparisons to previous history or adjacent poles. Additionally, readings of like bottles in equipment of the same make, model, and age can be used .

•The integrity of the vacuum bottle could be tested

•Open the circuit breaker

•Make sure the phase barriers are in place

•Connect the Line lead on the primary pole

•Connect the (earth/return) lead on the load side vacuum bottle pole

•Place a jumper on the two phases not being tested and jump them to ground •Remove all personnel from the test area

•Assign one person as a guard

•On the Hi-pot, turn the power on and gradually raise the voltage (in 1KV step, each step for one minute) to 10KV. Stay on 10KV only for one minute.

•If no disruptive discharge occurs which permanently reduces the test voltage to zero, the primary insulation system is acceptable

suppose the 6.6kV HT vacuum breaker is used to supply a HT motor of 500kW of same voltage level. what is the summation of Line currents(in kA) we see on numerical motor protection relay as statictics? Is it an indication for breaker wear?

Is it a one contact pair type or a two contact pair type?

Use a good telescope to investigate the surface, when open.

Add-on to #4.

Unless you are willing to measure milliohms precariously perched on 10 kV.

I very firmly pass on that task.

This information should be in the manual or application notes and varies between products, suppliers and usage (breaking current levels, etc). Your equipment may not even be serviceable once the contacts reach their end of life.

Read the circuit breaker documentation and if the answer is not in there then contact the manufacturer. Failure to do so could result in equipment damage and/or death.