Re: [CAD_CAM_EDM_DRO] Re: Phase converter for CNC lathe

In a message dated 4/30/01 10:48:27 AM Eastern Daylight Time,
dougrasmussen@... writes:

> Randy,
>
> I forgot to mention it in my response, but I think the best option in
> this case is to make the purchase conditional on the machine running
> on a phase converter. If a seller wouldn't agree to that, I'd walk
> away.
>
> This is a tricky deal, an older machine, fairly large spindle motor,
> and who knows what else will complicate the situation. You can bet,
> whatever problems come up, the seller will blame the phase converter
> and it may well be the cause. Personally, I'd think long and hard
> before committing to this purchase (unless I was very knowledgeable
> of the machine's control).
>
> Doug
>
>
>
>

Doug:

I agree with that assessment. When I worked for a large woodworking
machinery manufacturer we would not warranty any three phase machine with a
motor over 10 HP if used on a phase converter. The reason being that the
machinery was Italian and European three phase motors are NOT made to the
same specs as ones made here in the U.S. That is not to say they are in any
way inferior, in fact the specs on them were tighter and therein lay the
problem. They would not accept as large a voltage swing as the U.S. motors
do. Because of the negative experience we had with the converters on
machines over 10 HP it was decided by the powers that be to put a disclaimer
on the warranty. Also, the startup load is very important in choosing
whether to use a phase converter at all or not and in choosing the converter
itself if the decision is made to use one.

Regards,

Randy Abernathy
Woodworking Machine Specialist
4626 Old Stilesboro Road NW
Acworth, GA 30101-4066
Phone/Fax: 770-974-5295
E-mail: cnc002@...


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