Re: RSG motor

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "S & J Young by way of Terry Fritz <twftesla-at-qwest-dot-net>" <youngs-at-konnections-dot-net>

Greg,
A bench grinder typically uses an induction motor which approximately locks
to a integer fraction of the power line frequency.  For 60 Hz power, a bench
grinder typically will rotate at slightly less than 3600 RPM since it is not
completely synchronous.  Varying the voltage to them mostly varies the
available torque, but the motor still wants to run at nearly 3600 rpm.

What you need is a so-called "universal" motor which can run on either AC or
DC, and which uses brushes. A  vacuum cleaner,  portable electric drill,
router, angle grinder, or weed trimmer motor are typical examples of
universal motors which can be speed controlled with a variac or a SCR
dimmer.  A good angle grinder with tight bearings and not too noisy gears
will do very well, and comes with a good means of attaching the rotor to the
driveshaft.
--Steve
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, December 31, 2001 9:34 PM
Subject: RSG motor


> Original poster: "Mr Gregory Peters by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <s371034-at-student.uq.edu.au>
>
> Hello all,
>
> I was considering using a bench grinder to drive my asynchronous rotary
> gap. I hooked mine up to a small variac, but can not get any
> significant speed fluctuation. Does anyone know how I could vary the
> speed? Would a light dimmer work? The motor is a 2850 rpm unit. I was
> contemplating using 12 electrodes for about 570 bps.
>
> Cheers,
>
> Greg Peters
> Department of Earth Sciences,
> University of Queensland, Australia
> Phone: 0402 841 677
> http://www.geocities-dot-com/gregjpeters
>
>
>
>
>