RE: [CAD_CAM_EDM_DRO] VFDs and rotary phase converter

Hi Jon -

Do you mean I could use a 3-phase 208V input VFD and put in only
1-phase? I can understand needing to over-spec the VFD, but at
least that would give me options. I can't find any manufacture
that specifically sells a 1-phase input 5hp VFD.

Thanks,

Carlos Guillermo
VERVE Engineering & Design

-----Original Message-----
From: elson@...
[mailto:elson@...]On Behalf Of Jon Elson
Sent: Tuesday, January 29, 2002 2:28 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] VFDs and rotary phase converter

Unterhausen Umberto wrote:

> Carlos and Fitch were discussing VFDs and rotary phase
> converters.
>
> VFDs have trouble using single phase because of two
> factors: the size of the input diodes and the ripple
> voltage. However, if they have implemented some sort
> of phase checking for current draw, then you are out
> of luck with either the rotary converter or direct
> connect because you will get a phase fault.

Most modern (ie. 1990 or newer) VFDs will run fine on single
phase, at least up to 10 or 25 Hp. Larger (50 HP and up)
may have more sophisticated protection circuits.

Jon