View Full Version : RPC Electical problem

02-11-2005, 06:15 PM
Ok I am going to cover what I have. Most of you probably remember what I have but...

Lathe: 2 speed motor 3phase 3hp and 1.5hp
Phase-A-Matic phase converter (no run caps)
Idler Motor: 5ph 3phase

My problem. When I try running my lathe in the "High Speed" setting, it either flips the fuse or it has cause another fuse for a different part of the house to flip. I tried running the lathe at the lowest RPM (81) of the "high speed" setting and that is when it flipped a fuse for another part of the house but not the lathe. It does NOT cause any troubles when the lathe is run in its "low speed" setting.

My fuse is a 30amps at the box for the lathe which is running 220 directly to the lathe with nothing in between.

What am I missing?

Thank you all for you help in the past and for the future!!

02-11-2005, 07:20 PM
What size wiring from the fuse panel to the convertor?

Also, I have had problems with fuses and rotary convertors. Mine will blow a 30amp fuse just by switching the convertor in.

The entire circuit is protected by a 50amp breaker and my wire is #6.

I have even used slow blow fuses still no good. I dont have any shorts, it may just be an inrush from the caps (for mine). JRouche

02-11-2005, 07:30 PM
I ran 8 or 10ga.

I had a problem with the fuse popping when I flipped the switch too, till I started spinning the idler motor before i flipped the power swithed. That solved that problem.

I used slow to blow buss fuses also, but replaced the start box with a 60amp switch box with no fuses. If I didnt get my idler motor spinning fast enough before I flipped the power switch, it would blow the slow fuse. Was tired of spending a buck a fuse.

02-11-2005, 09:42 PM

are you saying you are starting the 5HP motor with start caps and then run it with no run caps? if so, this could cause a current and voltage imbalance that could definitely blow fuses. i start my 5HP idler, and then fire up the 5HP motor on the shaper (and everything "grunts" for a few seconds) and i have never blown one of my 20A fuses. i think all my wiring is 8 ga.

andy b.

02-11-2005, 09:46 PM

I dont have run caps. Peter on the the PM website said run caps should fix the problem.

I will be ordering some and figuering out where to put them.

02-12-2005, 11:01 AM
Cuemnaker, if your blowing fuses on a branch circuit that your lathe is not connected to you have another serious problem. I would call an electrician to trace all your circuits. Uncrichie