Re: inductor current limiting for MOTs

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

Original poster: "Paul Benham by way of Terry Fritz <twftesla-at-qwest-dot-net>" <paulb-at-woodanddouglas.co.uk>

For my 2.5" secondary coil running from two MOT's in series(primary's in
parallel), I have four MOT's in series with the incoming mains supply for my
ballast.

The ballast MOT's all have their HV outputs shorted out, and they are all
grounded to mains earth.  It runs around 200W input power with this
setup(240V 50Hz input).  I loose about 90V across the ballast, so I just use
a variac set up for step-up operation.

My primary cap is 13.6nF, and no resonant rise problems have been seen.  I
am using a static gap.

Interestingly, when I had PFC directly on the two MOT's in series it ended
up resonating with my ballast, and I had to remove it.  If I add it again,
it will be added at the variac output, before any ballast.

Cheers,

Paul B.

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, July 08, 2002 3:16 PM
Subject: inductor current limiting for MOTs


> Original poster: "Laurence Davis by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <meknar-at-hotmail-dot-com>
>
> I've gathered a few MOTs and realized that I have to current limit
> them.  I want to build a small static gap coil with 1 or 2 of them.
> Some of the people running MOTs have used inductive current limiting.
> However I don't know the equations for calculating the
> inductance required.  can someone point me towards the equations?
> What shape of core should i use for the choke;
> cylindrical or toroidal?  And to choose the material... I'm assuming the
> current limiter would be placed before the chokes limiting the feedback
> of the high frequency from the primary tank circuit.  Therefore the
> frequency would be 60hz.
>
> thanks, larry d.
>
>
>