RSG opinions?

From:  RMC [SMTP:craven-at-globalnet.co.uk]
Sent:  Sunday, April 05, 1998 4:37 PM
To:  Tesla List
Subject:  RSG opinions?

I can buy a new 6" bench grinder in England from B & Q for twenty

It is a 3000rpm  half-HP motor (synchronous, I believe i.e. not a low
slip induction motor) and is intended to run a pair of grinding disks
(one on each end of the motor shaft).

If the effective mass of the RSG disk is less than or equal to that of
the grinding wheels it is replacing (such that torque loading will not
change), I might be able to modify the bench grinder to take at least
a 9" or even a 12" disk.

My intention is to make a couple of disks from Tufnol or similar rigid
insulator, with 12 contacts. The contacts will either be

tungsten carbide machine tool inserts    or
Copomel tungsten/copper (70/30)

these two materials cost less than elemental tungsten but have similar
relevant properties i.e. they don't melt and they're very hard. The
is still high and it means that it might be better for me to buy a
RSG from BillWysock, for example.

I will have four static contacts such that the switching path is onto
and off both wheels: 4 series breaks. This could be doubled up by
then going back through the disks on an opposite contact, so to speak.
This might negate the need for A Richard Quick cylinder quench gap.

It's for a 10kV primary running at 3-4 kVA upto 10kVA.

I would welcome :

1. Comments on using 2 wheels and upto 4 or 8 breaks in series
2. Comments on Copomel vs tungsten carbide vs tungsten vs thoriated
tungsten at 10kW
3. Comments on using 6" diameter rotors

Any comments or criticisms would be very welcome. My first RSG was a
bad job due to poor motor end-float and the fact that I used stainless
steel. And the fact that I'm not a mechanical engineer.

Richard Craven, Malvern, England.