Re: Spindle Motors

2f. Re: Spindle motors
Posted by: "Jon Elson" elson@... jmelson2
Date: Wed Aug 29, 2007 9:42 am ((PDT))

I have a Rockwell/Precise 54,000 RPM ball bearing spindle that
is intended for production work. It can mill or grind, and came
with a 1/8" carbide end mill in it. It is rated at 3/4 Hp.

I also have a Westwind air bearing spindle, designed for at
least that much speed. Due to the air bearings, it can run all
day for years.

>
>>As discussed I think heat removal will be a problem.
>

Both of these motors are air cooled. The Rockwell/Precise has a
filter on it, but I'm guessing that is to keep dirt out, it
seems positive pressure has to be a better solution. The
Westwind uses compressed air, which is easy to come by as it is
the same air used for the bearings, but it uses a LOT of air for
cooling - not too efficient. Newer Westwind motors are water
cooled.

I run the Westwind on a standard VFD with series inductors. It
is a traditional induction 3-phase motor, just very long and skinny.

The Rockwell/Precise is a 2-phase motor, and I haven't built up
a drive for it yet, although I have designed it.

Jon

Hi Jon;

[I've got a Rockwell/Precise spindle too, and I was wondering about how to
slow it down. Are they all 2-phase? Would a regular cheapie "router speed
control" work, or would that lose all my torque? Care to share anything
about your drive design?]

Andrew Werby
www.computersculpture.com