RE: SISG MOT system ballasting question?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Mark Dunn" <mdunn@xxxxxxxxxxxx>


Terry:

My coil is MOT based and uses an MOT inductor to ballast the primary
side.  I take a saws-all and cut the I-core loose from the E-core(be
careful to cut thru the center of the weld so the laminations don't fall
apart).  Then the secondary can be removed and discarded and the primary
used.  Typically, an MOT with primary alone has about 100 Ohms impedence
and thus 250 mH inductance at 120volt and 60Hz.  By shimming the I-Core
you can drop the inductance to what you need.  You can also take
windings off of the MOT primary(Most MOT primaries have 100 Turns).

Dr. R's numbers for you inductive ballast are based on a power factor of
1.0.  MOT's have terribly low power factor so for your 280 watts you
will have in excess of 600 VA(My eperience with MOT's).  Thus you will
need to current limit around 5 amps which would mean 24 ohms reactance
and 64 mH of inductance(Dr. R was figuring only ~2.5 amps).

Based on my data for this you should need ~ .040" shim to get 64 mH on a
MOT similar to the ones I use.  If you don't have what you need for
this, I have an MOT and could modify it and test it on Sunday and ship
it to you Monday(I'm out of town until Sun AM - contact me at my home
e-mail).

Mark R Dunn, P.E.
Engineering Manager
Wm. W. Meyer & Sons, Inc.
847-673-0312 x244

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-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Wednesday, May 17, 2006 8:53 PM
To: tesla@xxxxxxxxxx
Subject: SISG MOT system ballasting question?


Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi,

I have been working on collecting parts for the 280W SISG
system.  Tons of parts come in tomorrow.

But I am a little "stuck" on "how" to ballast the MOTs.  It is a dual
MOT full bridge rectifier.  The MOTS charge a 150nF cap to 5600V at 120
BPS.

http://hot-streamer.com/temp/SISG-MOT-System.gif

My brain is sort of fried at this point and I never have played with
ballasted systems before...  It is run off a variac so there is room
to play...  I was going to model it and all, but fighting the models
will take hours...  Maybe someone just knows the value of inductor or
resistor it needs?  *:-))

I got the "parts" to make anything...

The SISG will fire at 5600 volts, so I need to recharge the 150nF cap
at 120BPS for 282 watts of fun ;-)

I was going to figure it out tomorrow morning but the county ran an
earth mover into a fence...  So I will be in the mountains tomorrow
stretching wire...

Cheers,

	Terry