Experience with MV Contactors
Experience with MV Contactors
(OP)
Hello,
I am working on replacing 1950's vintage circuit breakers on the output of 800 kW hydro generators. One proposal I have received is using MV contactors instead of circuit breakers. The generator output is 2400V delta and the system fault current is around 6kA.
Does anyone have any experience using MV contactors in this type of application?
Thank you
I am working on replacing 1950's vintage circuit breakers on the output of 800 kW hydro generators. One proposal I have received is using MV contactors instead of circuit breakers. The generator output is 2400V delta and the system fault current is around 6kA.
Does anyone have any experience using MV contactors in this type of application?
Thank you






RE: Experience with MV Contactors
RE: Experience with MV Contactors
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Experience with MV Contactors
RE: Experience with MV Contactors
Be very careful if you wanting to use vacuum-contactors, even more so in this case, because you want to use it on an old machine. Due to different contact materials and operating speeds, (contactors vs circuit breakers) contactors are much more prone to pre-strike (switching on) and re-strike (switching off) voltages, which may stress and puncture the coil insulation. Although the vacuum-technology has improved a lot over the last years, it might be a problem due to lower BIL-ratings (BIL = breakdown insulation level) on older machines. Modern machines are normally designed to have a much higher BIL-rating than previously.
Nicely picked up, Gunnar. Like Skogs said, if you are going to use it, do not use it without arresters.
Regards
Ralph
Failure seldom stops us, it is the fear for failure that stops us - Jack Lemmon
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