New Power Feeder, or Phase Converter?
Advice on how to run an old 3-phase power feeder when moving to a location without 3-phase power. May 18, 2010
Question
I have only one 3 phase machine in the shop, an elderly but very reliable power feeder. I have it set up on my shaper and on my table saw, which are the only two machines I use it on. Just moved to a new shop where there's only single phase. Think I'd be better off getting a new feeder or a phase converter?
Forum Responses
(Solid Wood Machining Forum)
From contributor G:
If you buy an Add a Phase type unit, a static converter, one of those little capacitor boxes for about $75 bucks, you can go on with old faithful, but she will have lost 1/3 of her hp (unless you load it heavily, that would not be an issue.)
All other solutions such as a rotary phase converter would cost quite a bit more, as would one of the VFD or electronic magic boxes. Might be worth it in the long run, as most better feeders seem to be three phase (if old faithful ever quits or you need the horsepower).
From the original questioner:
Very interesting. This is my first experience with needing a phase converter. I'd never heard of the Add-a-Phase type of converter. It sounds perfect for Old Faithful!
From contributor R:
Do a search for a static phase converter - there are tons of them on eBay. Make sure you buy one sized for the motor you intend to run. You would be far better off with a rotary unit and it would still cost much less than a new feeder.
From the original questioner:
If the info I read online is accurate, the static type converters just get the motor going on 3 phase, then the motor actually runs on single phase after that. Is that right? And this accounts for the diminished power? So the rotary type is what you would recommend?
From contributor D:
Or, you could add an AC drive and have full power and variable speed control.
From contributor R:
I agree - an AC drive is a good solution for older lathes and shapers or other machines where variable speed control is needed. A feeder normally has enough range of speeds to negate this function.
From contributor M:
Very common problem. Lots of good solutions. To get going do a few things:
(1) Find out the size of your current meter base. It will be rated in amps. If you can't find that information, find out how big the main breaker in your service entrance panel is.
(2) Find out if you can upgrade to three phase and if so, at what cost.
(3) Find out if you can go to 400 amp single phase service. This can be cheap sometimes.
(4) Get the HP ratings from your motor.
(5) Do a mental inventory of your shop and ask yourself if you could use real 3 phase in a way that reduces time/cost, etc. One of those etcs is the size and price of motors and machines that use high HP single phase motors.
(6) You need a lot of this information before you go too far. For example, a true rotary phase converter can require as much as a 125 amp single phase circuit to operate a 15 HP 3 phase motor. Basically, nothing is free.
