Re: Choke Chat

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

Original poster: "Michael H Nolley by way of Terry Fritz <twftesla-at-qwest-dot-net>" <nolleym-at-willamette.edu>

>  I could use easy-to-wind round bobbins.
> I would wind these with about 5000 turns each of 28AWG
> and use one choke on each leg of the DC PSU output. I
> have no idea how to estimate the inductance of such a
> choke. I'm thinking I would drive the thing with two
> series MOTs for 4kvac into a full-wave voltage
> doubler, and use the chokes to bump the resulting
> 12kvdc to roughly 20kvdc.

    The problem with the straight core idea is that the resulting
inductance is less than if a
transformer core or "closed" core is used.  The Mot is ideal in this case
because it is already
there--i.e. you already have the core in place.  It is no problem to remove
the primary and add a second
secondary in series, since the primary isn't being used anyway.  This
doubles the inductance and gives
you about 4000 turns.  A couple of these would be plenty I would think.
You'd need to grind off the weld
beads on 4 Mots, but this is surely easier than a homebrew core IMHO.  To
avoid saturation, you could gap
them, or use fairly massive cores--the former probably being the best
solution.  Once the weld beads are
gone, gapping the core is easy:  just space with strips of thin plastic
(overhead films, perhaps) and
re-assemble using hardware store screw clamps.
            --Mike