[Fredrik88]

I am doing a retrofit on a Dynamyte DM4400.

I am going with Centroid Acorn for the moment and have the drives and new steppermotors all wired in and ready.

But i am having questions regarding the spindel. And my plan is to use a VFD. The problem is i can only find VFD´s with the output of 220v.
And the spindelmotor is rated to 180v. Do anybody have a suggestion on where i can find a VFD that works with this spindelmotor?

[Jim Dawson]

Many VFDs have an setable maximum output voltage.

[Fredrik88]

Ok, Thanx for quick answer.

Im looking at something like this. But this one and many others say that they are in the range of 204-240volt.

https://www.ebay.com/itm/7-5KW-VFD-1...gAAOSwJkJWlLX2

[Jim Dawson]

The voltage they are talking about in the ad is the maximum output voltage, based on the input voltage. The settable output voltage is different, but you would have to have the manual to be able to determine what the setable output range actually is. My VFD has a minimum possible setting of 200V, which by good luck is my 7.5 KW spindle motor nameplate voltage.

Could you run a 180V motor at 200V? I suspect it would work fine, that's +10%, close enough I think. But look at the nameplate amps on the motor and make sure the VFD is rated at least the nameplate current.

What kind of machine spindle would this be running? Lathe, Mill, Router?

[Fredrik88]

I have added a picture of the nameplate of the motor.

The motor is on a mill.

[Jim Dawson]

That is a DC motor, you are not going to be able to run it on a VFD

[Fredrik88]

Dang, Thant no good. What are my options?

[Jim Dawson]

Maybe you can interface the Acorn with the existing spindle drive. The existing drive should take the same inputs as a VFD, so if the Acorn can run a VFD, then it should run the existing drive. If you have a electrical diagram of the original panel it might not be too hard to sort out.

Failing that, I see a new spindle motor and VFD in your future. You linked to a 7.5KW VFD above, is your spindle actually 7.5KW?