Re: Phase converter for CNC lathe

Randy,

Interesting what you say about the European motors. I have an Emco
Mairer (sp?, I should've learned to spell it by now) CNC lathe which
I purchased new 14 years ago. My purchase was with the guarantee it
would run off an Arco phase converter that I already owned. The
spindle motor is rated around 6 hp. It runs fine most of the time,
except when our line voltage drops, like around dinner time. Then
the machine errors out, with a "spindle drive not ready" message,
which translates to, "shut down for the day and come back tomorrow".
For whatever reason they set these machines up to be very sensitive
to incoming voltage, but that sensitivity only affects the spindle
motor, everything else works in a low voltage condition.

Like other European machines I've seen this one came with a multi-tap
transformer because it runs on 380V, 3 phase. You can switch the
transformer leads around to get it to run with most any line voltage
condition, we've setup for the most common line voltage which is
fairly steady from morning to late afternoon. Incidently, forget
about even trying to run on Thanksgiving or Christmas.

Doug

--- In CAD_CAM_EDM_DRO@y..., cnc002@a... wrote:
> In a message dated 4/30/01 10:48:27 AM Eastern Daylight Time,

>
> 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@a...
>
>
> [Non-text portions of this message have been removed]