[jderou]

I have the opportunity to purchase a CNC Bed mill. It is currently running off 480 3 phase. Of course I only have 220 single available. The spindle is the only part of the machine that is wired for 480. The VFD accepts 360-480 input power. So it either I build/buy a step up transformer then add a RPC, or I replace the VFD with 220x3 plus RPC, or replace with a 220x1 VFD.
Or does anyone think it could be possible to rewire the VFD for 220?
This is for a 7.5hp spindle.
I am also wondering if I can build a step up transformer out of an old 180amp stick welder.
Thanks!
Joe

[underthetire]

Even if you change the VFD to a 220 unit, whats the motor rated for? If you can't re-tap the motor for 220, it would be a waist of time and money.

[Al_The_Man]

The motor is getting a bit large to run off of 220 1ph VFD, that is if it is a 220/480 volt motor?
It is quite possible that the rest of the machine is ran off of either a 480/120v 1 phase transformer or an internal 480 to 220 3ph then to 120v 1ph.
It is best to check out schematics to see exactly what you need in the way of 3ph?
Al.

[jderou]

Right now I am assuming the motor can be rewired for 220v. The rest of the machine, servos and all, is 110v, and is wired with a separate 110 plug.

[Al_The_Man]

. The rest of the machine, servos and all, is 110v, and is wired with a separate 110 plug.

It sounds like a bit of an amateurish conversion, normally you would have a disconnect with relative fusing and possibly a 460/120 transformer?
With spindle control integrated with the controller?
Al.

[jderou]

It is an Anilam control. I always thought it was a bit odd, but it is how they recommend it. Spindle control is integrated with the VFD.

[Al_The_Man]

BTW re- using the stick welder, if it is one of the older SMAW transformers, it is most likely variable reactance type, the voltage collapses proportionally as current increases.
Al.

[jderou]

Good point on the stick welder, how would I know if it was this type? This one has a sliding mechanism that goes into the core to change reactance.
Just checked the motor, it can be rewired for 220v.

[Al_The_Man]

Good point on the stick welder, how would I know if it was this type? This one has a sliding mechanism that goes into the core to change reactance.
.

That is it, no good for a regular supply transformer.
Al.