200bps even firing was RE: [TCML] Setting optimal phase angle of SRSG motor

["Phil Tuck" <phil@xxxxxxxxxxx>]

Gary et al
You can get even firing with 200bps. Richie B has a PSpice simulation you
can download and my own spice trace (using his downloads) can be seen here
http://www.hvtesla.com/phase.html
2nd picture down.

You normally can hear a change in sound. At 200 bps you have a slight rasp
to the sound which disappears when it is in sync. (Got it on a YouTube video
somewhere where you can clearly hear it - no idea which one though)

I would love to have 100bps as it sounds better, but based solely on PSpice
simulations it seems with power over 5kw you need some caps that can take
some high voltage peaks of 50Kv or more, unless your very, very careful when
adjusting the phase.  Using an MMC is just not practicable at this size and
peak voltage handling. 200 bps keeps the peak voltages down and my 100nF
34Kv MMC handles it nicely and the 0.36 inch safety never fires (input 12Kv
pig)

Regards
Phil

www.hvtesla.com


-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of Gary Lau
Sent: 07 December 2010 19:42
To: Tesla Coil Mailing List
Subject: Re: [TCML] Setting optimal phase angle of SRSG motor

I assume that your electrodes are equally spaced, 90 degrees apart.
I'm not sure that it's possible to get all bangs the same size at 200BPS by
adusting just the motor phase, without some very deliberate electrode
geometry considerations.  The trouble is, the rate at which the cap charges
is non-linear with respect to time.  So instead of the fixed electrodes
being at 12, 3, 6, and 9 o'clock, they may need to be at 12, 2, 6, and 8
o'clock (picking numbers out of the air).  I think it was Finn Hammer who
posted that he did some PSpice simulations to determine the necessary
electrode placement for 200BPS.  I would guess that whatever geometry worked
for Finn would work for you, if he was willing to share.

Just curious - why 200 rather than 100 BPS?

Regards, Gary Lau
MA, USA



On Tue, Dec 7, 2010 at 12:19 PM, Teslalabor <teslalabor@xxxxxxxxxxx> wrote:

> Hi,
> I actually try to find out the optimal phase angle position of the 
> motor in my 200bps SRSG. I use a dummy load with halogen bulbs. I am 
> not sure WHAT exactly the optimal point is! Is it, when the 4 
> firing-sparks at the 4 electrodes seem to be of the equal "size" / 
> brightness when variac is at full voltage or when the bulbs are of 
> highest brightness (but this is not easy to see!) OR is it the point 
> where all 4 electrodes begin firing at the same time when rising the 
> voltage on the variac? But in this case, 2 of the
> 4 electrodes seem to fire much brighter then the other 2, when variac 
> at full voltage. So I am a little bit confused, which point I should take.
>
> Stefan
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
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>
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