Toshiba VCB
Toshiba VCB
(OP)
I am looking at a Toshiba VCB that was used as a contactor for a 4160-V motor. There was an arcing fault at the contactor. Does anyone have experience with this type of failure? Especially with a Toshiba VCB?
Thanks
Thanks






RE: Toshiba VCB
I have used a lot of Toshiba vacuum contactors on 4160V and beyond. I have never had an arcing problem. Arcing faults in MV gear can happen from a lot of things, but IMHO if there were a design problem in the contactor, it would be immediately evident to someone like Toshiba who sells thousands of them every month.
I have had moisture problems in MV cabinets that allowed tracking from the terminations to the back panel, which once it happens, is very difficult to correct without rebuilding your isolation system. But that isn't really a problem with the contactor design.
I have also had GE vacuum contactors that failed to ground during UL testing because GE had reduced clearances in their LimitAmp gear at some point and apparently never retested with UL. But that was not technically a contactor design problem either and was easily solved.
I've had a flash-over in Joslyn gear from the contactor terminals too, but that was after a voltage event that cause some MOVs in the same cabinet to vaporize, which provided a flash-over path through the ionized atmosphere in the cabinet. Again, not a design problem with the contactor.
Describe your event in more detail.
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RE: Toshiba VCB