Today I went to use my planer (3 phase, 9 HP) and when it wouldn’t feed the board, I realized that the motor (cutterhead and feed works) was running in reverse. Strange. There was way more contact “chatter” (clicking) than usual from the starter when starting the planer with subsequent test starts to confirm motor direction 2 or 3 times it clicked a lot, started to rotate for 2-3 seconds then turned itself off. It did eventually start and run but was confirmed to be running in reverse.
Confused, I then tested the table saw (3 phase, 5 HP) and had no problems starting it but it was also running in reverse. This would indicate that the change is coming from the rotary phase converter - detailed below.
I have not switched any leads in the last week since I last used the machines (that were running in normal rotation) and I’m the only one in my shop.
I am familiar with changing 2 of the leads to change direction (normally) when wiring a 3 phase machine.
I have a Kay Phasemaster RPC that is rated for up to 10 HP from any single motor. It is on a 60 amp single
phase breaker from my 200 amp panel and has never given me any issues before. It has always started the planer (largest load by far) just fine.
What would cause sudden change of motor rotation in this situation??
I called my electrician and chatted with him about it; he seemed stumped. he walked me through a few multimeter tests that I did on the RPC itself - ohm test of the fuses, checking voltages on the 3 phase output side. Unless I’m an multimeter idiot, then I think the fuses tested good. On the RPC output side, the voltage from 2 of the legs was steady fluctuating around 240 (+/- 2) and the 3rd leg tested closer to 230 V (+/- 2).
I have not changed any leads on plugs/receptacles at this point. I could, of course, try that on the (1) 3 phase 30 amp receptacle I have on the output side of the RPC and see what happens, but figured I’d ask here before I did that.
I can’t understand why the direction change would happen suddenly like this on its own. The starter clicking / chatter / resistance / whatever you want to call it was also new and seems related, but I’m no electrician and only have the most basic understanding enough to wire simple things like receptacles, plugs and sometimes switches.
Any help is appreciated. Electrician can’t come until Thursday at the earliest and the downtime is not so good for the commission work I was starting on when this happened! Thanks in advance !
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