Re: NEW member Suitable conversions?

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