Which phase?

[gltapley]

Mostly a question for you builders out there who have basically a full machine shop at your disposal. Did you convert your electrical feed to 3 phase or did you stay on single phase and use an inverter.
I know that a tool made for 3 phase is more efficient than single phase but the cost of conversion can be a little daunting...plus if you are not running the machine (knee mill or lathe. etc) all day long then the machine is not that big an electric pig. Three phase is definately cheaper to run.

Just trying to see what you folks have done.

GTapley

[EricKeller]

I use one VFD per machine. Phase converters using a motor are an acceptable solution. However, a VFD has many benefits. First, they soft start the motor and they are variable speed. Generally, phase converters are used with more than one machine so you have to have special wiring whereas a VFD would be wired into a single phase circuit.

I can't get 3 phase where I am, and it seems that the electric companies are rather proud of 3 phase wiring in places where it is available. I think for everything but a compressor, three phase isn't really all that beneficial. I would never put a single phase motor on a 3 phase machine if that is one of the options you are considering.

[gltapley]

Eric,

Thanks for the info. You confirmed most everything I wanted to know. At my day job with Intel Corp the piece of equipment I maintain uses AC and DC motor controllers for everything here at work all of our large motors are 3 phase 400 volt units with sophisticated controllers very similiar to what you are talking about. Really I just wanted to see how many folks out there had spend the big and I mean big $$$'s to convert to 3 phase. You were a wealth of info and agiain thank you very much for the reply.

George