ECN Forum Forums General Topics of the Trade General Discussion Area 480 Open Delta voltage readings

The winding between the 87 and 401v legs is shorted to the case is my bet. I bet the ohm readings are just about the same proportions too.

Greg,

The ground monitor would not help in this situation, since it is already known that there is a problem.

However, in the future, immediate attention could be given to the first ground fault. Ignoring the first ground fault can lead to more serious problems when a second ground fault occurs on another phase. These faults can have a fairly high impedance so OCPD's may not trip and fires can occur.

There is a listed product on the market that has the 3 lights and there are more sophisticated products which provide relay outputs. I, too, prefer an audible alarm since the building occupants may not realize the dangers involved. A light being out is easily ignored, but a horn sounding is not (of course, they might fill the horn with shaving cream to quiet it down).

For those interested, here's a pair of sites to visit
http://www.bender.org/irdh.aspx
http://www.atcdiversified.com/Diversified/GFD_series.htm

" (of course, they might fill the horn with shaving cream to quiet it down)."

Round here it would usually be filled with a ball peen hammer

Most common here is "Cut the red wire" (pool door alarms).

Good call gentlemen!!! The motor in question, ran nice and cool and sounded normal. However....a meg test revealed it to be faulty.
Thanks a lot!!