[ianagos]

So here is the reason they need to have a Transformer there is always a reason electrical engineers design things the way they do

The Fadal requires the incoming voltage to be with in a controlled voltage for there VFD Drives they are using this is so it will not fail from over voltage, from the Fadal spec's I found these specs for the reasons why

The spindle inverter must have incoming voltage between 190VAC and 240VAC MAX. If you
underrate the voltage or push above 240VAC you are asking for an early failure. The amplifier
chassis is not quite as critical, but under voltage is a real
problem. It causes the amplifiers to push additional
current to make up for the under voltage condition and
can keep the amps in a redline situation; and that's never
good.

So the normal NA supply in most areas is 245v and can be higher so if you direct wired to a Fadal CNC machine that was using a Fadal VFD Drive it would not last very long without voltage regulation

So for those that are doing a single Phase connection and your machine has the Fadal VFD Drive than you will need to protect the VFD Drive form over Voltage or it will fail if you have a direct connected 240v Power supply using L1 / L2

I agree with what you are saying and the vfds fadal used especially the amc drives are extremely sensitive to over voltage and that’s the whole reason I suggest keeping the transformer in. I’ve now blown 2 amc drives due to over voltage.

Some of the other drives are more tolerant than the amc but his machine has an amc drive.

Mactec do you have a company that rebuilds vfds? I have an amc that is blown I’d consider sending your way.