Re: ARSG Motors (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sat, 25 Aug 2007 19:57:44 +0000
From: David Rieben <drieben@xxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Cc: drieben@xxxxxxxxxxx
Subject: Re: ARSG Motors (fwd)

Hi Chris, 

Most asynch rotary gap coilers get excellent results with 300 to 500 
BPS. With a disc with 8 flying electrodes, 3600 RPMs would yield 
480 BPS. I have seen some ARSGs that are set up with 10,000 RPM
universal drive motors but their input voltage is almost always "toned
down" with a variac and most seldom run their RSG at the full rated
10,000 RPMs. My ARSG on my Green Monster coil only goes up
to 3500 RPMs with a treadmill motor and 8 flying electrodes and that
is plenty fast as I usually get the best results wiht the speed control 
variac set around 75 to 80 on the 0 -100 dial. Of course, with a
SRSG, you want a break rate that's a direct multiple of the 60 hz
(50 hz for those coilers across the big pond) of the mains power supply
(usually 120 or 240 BPS for 60 hz , 100 or 200 BPS for 50 hz).

If the BPS get's too high, the transformer dosen't have enough time
to fully charge the primary capacitor between each bang and therefore
each bang will fire at a reduced voltage. I'm sure others can explain the 
theory better but there's a point where the reduced capacitor discharge
voltage is no longer able to keep extending the ionized path and from 
that point on, the sparks will get shorter, not longer, with additional in-
crease in the BPS.

Also, the centrifugal and vibrational forces on the rotary disc will increase 
as the square of the RPMs, so running relatively high RPMs (>5000) on any 
homemade disc, other than a very precision made, professionally  machined 
one, can be quite dangerous.


David Rieben

-------------- Original message -------------- 
From: "Tesla list" <tesla@xxxxxxxxxx> 

> 
> ---------- Forwarded message ---------- 
> Date: Fri, 24 Aug 2007 10:39:45 -0500 
> From: Crispy 
> To: Tesla list 
> Subject: Re: ARSG Motors (fwd) 
> 
> What is "too fast" for an ARSG? Is it just power consumption, or is 
> there another issue? I may be wrong, but it seems to be that the faster 
> the speed on the ARSG, the more frequent bangs, and the better old 
> ionized trails help new sparks extend to new lengths by being allowed 
> less time to dissipate. 
> 
> Chris 
> 
> On Fri, 2007-08-24 at 06:42 -0600, Tesla list wrote: 
> > ---------- Forwarded message ---------- 
> > Date: Fri, 24 Aug 2007 15:11:19 +0930 
> > From: The Engine Centre 
> > To: Tesla list 
> > Subject: Re: ARSG Motors (fwd) 
> > 
> > A washing machine, spin motor or a main motor, most are universal brush 
> > motors,they are easy to get and cheap, i have one which runs 13000 no load, 
> > which is far too fast BUT with a small variac you can control the speed to 
> > what ever you want. 
> > Paul,--- Original Message ----- 
> > From: "Tesla list" 
> > To: 
> > Sent: Friday, August 24, 2007 12:34 PM 
> > Subject: ARSG Motors (fwd) 
> > 
> > 
> > > 
> > > ---------- Forwarded message ---------- 
> > > Date: Thu, 23 Aug 2007 21:51:14 -0500 
> > > From: Crispy 
> > > To: tesla@xxxxxxxxxx 
> > > Subject: ARSG Motors 
> > > 
> > > Hello, 
> > > 
> > > Can anyone suggest reasonably fast (10000rpm+) and cheap motors for 
> > > building a propeller-type ARSG? I found some very cheap angle grinders 
> > > ($5 a piece, $15 shipping, 11000rpm) on ebay, but they use 600W, which 
> > > is more than I can support. The motor doesn't have to be that cheap 
> > > either. The imposed total limit is 800W, and the power supply will be a 
> > > 12/30 NST (360W). Thanks a lot. 
> > > 
> > > Chris 
> > > 
> > > 
> > > 
> > 
> > 
> > 
> 
> 
>