Re: NEW member Suitable conversions?

A 3400 rpm motor is better than a 1700 rpm motor and if you have a pulley on
the motor for additional flywheel action it is even better.
Darrell

----- Original Message -----
From: <paul@...>
To: <CAD_CAM_EDM_DRO@onelist.com>
Sent: Friday, February 18, 2000 4:27 PM
Subject: Re: [CAD_CAM_EDM_DRO] NEW member Suitable conversions?


> From: paul@...
>
> Bigger doesn't cost that much to run. The general rule of thumb is to
have
> a motor for your phase converter about 1.3 times bigger than what
> you want to run, so a 7.5 Hp would be fine for a 5 Hp motor.
>
> I use a 5 Hp idler with my 5 Hp LeBlond which leads to some unpleasant
> results when reversing the lathe (ocasionally, the phase converter will
> jump and reverse, leaving the lathe turning in the same direction. This
> is NOT good when threading to a shoulder - I have since added a thread
> dial so this isn't the problem it was, but there are situations where
> you'd want to reverse and stop the spindle quickly)
>
> When you have your mills running, they act as additional idler capacity.
> It works; the only question is how many machines so you want running
> to be able to get something done. My personal preference is to have
> only one machine on at a time - less to worry about.
>
> There are a number of good urls for phase converters, you can probably
> find something off of www.metalworking.com or the Metal Web News
> http://www.mindspring.com/~wgray1/
>
> Paul
> >
> > From: "Darrell" <dgehlsen@...>
> >
> > 15 HP for the converter sounds like over kill. Do you have anything that
is
> > 15 HP that you need to run?
> > I have a 5 HP converter and it runs my 5 HP lathe and two 2 HP mills all
at
> > the same time. In fact, if the mills are running the lathe seams to
start
> > easier. I think the phase converter only needs to be big enough to start
the
> > largest machine. After that, the other machines give additional power so
> > that if you had a 5 HP converter and a 2 HP mill running you could start
a &
> > HP motor.
> > As to the capacitor start, you need extra capacitors to start the
converter
> > and then drop some out to run. Capacitors really help balance the
voltage
> > and increase the efficiency.
> > Darrell
> >
> >
> > > I already got a 15 Hp 3 phase motor to build the converter.
> > >
> > > I have a motor and an electric clutch from an old copier salvage job.
> > >
> > > I figured on spinning the large motor up with the small one, and then
> > releasing
> > > the clutch and kicking in the relays to run it.
> > >
> > > I hear it should be possible to do the same thing with some caps, but
if
> > it
> > > doesn't start correctly just one time, it will burn up.
> > >
> > > A circuit to get the motor and power line in sync before kicking in
the
> > > relays would probably be a good addition.
> > >
> > > The drive motor for the lathe spindle is rated at 5 hp.
> > > It in turn runs the spindle with a single 1/2" V belt. Go figure.
> > >
> > > I even bought half a dozen 6" chunks of steel pipe, I don't know where
> > they
> > > went, but I bought them ;-).
> > >
> > > Marc
> > >
> > >
>
>
> --
> Paul Amaranth | Rochester MI, USA
> Aurora Group, Inc. | Systems & Software
> paul@... | Unix / Windows / NT
>
>
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