Can I convert single phase motor to three phase?
I have a compressor motor that is blowing the starting capacitor. I have checked the voltage and it is fine. I was wondering if I could just convert this motor to three phase and eliminate the starting and run capacitor.
I have searched and found tons of articles about converting three phase motors to single phase. I am sure it goes both ways, but I was wondering if someone else had already done this. I have three phase in my shop and converting this motor to three phase would be cheaper than buying a new three phase motor.
I have no idea why it is blowing caps, but I suspect that it is from too many starts per hour.
Any help is greatly appreciated.
Jim
Similar problem I had years ago - but solved as well
I had the same situation years ago on my compressor. It runs a 5hp Century (I think that's the brand) motor with both a start and run cap. Problem was a partially worn slip ring surface on the centrifugal switch. That lead to a high current load on start and poof! Man did that make a mess - LOL. I ended up giving the motor to the local rebuild shop for a good going over and bearing replacement as well. The price was well worth it (something around $60) and I grabbed a couple of extra caps as spares before I walked out.
On the subject of motors and phases mentioned in this thread no one ever seems to mention that on a single phase system both phases are 180 degrees apart due to transformer coupling at the pole (residential) and not the 120 degrees I think many are assuming and might lead to some confusion. I was told this, researched it and verified this many years ago by doing a phase measurement with o-scope on the home ac line. (measured in my home but that could be different elsewhere.) On a true three phase system you'll have that 120 degrees of separation between phases.
On a rotary phase converter you start with two phases 180 degrees apart (from residential power) and produce the third phase close to the others by adjusting the power factor with capacitance. Ultimately you will loose efficiency in the conversion but make up the difference in cost savings from not having to purchase industrial power. I spent much time researching phase converters and I could still have it wrong. (hope not!) so I invite someone to set me straight if need be. I should have a 7.5hp 3PH motor in my grasps to play with shortly down the road. The entire concept of RPC's just seems fun to get involved with and a lot cheaper than a frequency drive of similar hp at the moment.
Sounds like you solved your motor issue for sure. Just thought I would had a couple of words while reading the posts I missed over the last month or so.