Re: Air Gap MOT Reactor

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

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



> Original poster: "S & J Young by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<youngs-at-konnections-dot-net>
>
> Recent Tesla List wisdom from Ritchie and others indicates DC charging
> reactors really need an air gap in them so they don't saturate as easily and
> lead to power arcing in RSGs.  So I decided to sacrifice one of my salvaged
> MOTs and convert it into an inductor with an air gap.  It turned out to be
> much easier than I anticipated.

Great work!

> My MOT measured about 19 Henry before surgery.

    That's somehow more than I expected.  Cool.


*snip*I removed the shunts, primary and filament windings, leaving just the

> secondary.  I then measured the inductance for various gap thicknesses
> (using post-it squares as spacers).  Here are the approximate measurements
> of gap thickness vs inductance in Henries:
> None = 16.5 Henry
> 0.004 inch = 13.8
> 0.008 = 12.0
> 0.015 = 9.6
> 0.03 = 7.4
> 0.06 = 5.6
> Infinity (no "I" core) = 2.5

    a mil is .001 inches, so the first thickness is 4 mils and the last is
60--for those of you who
will be making plastic spacers.

> After I retune my twin TC for a bigger MMC I just finished, I will try the
> following experiment:  With no reactor air gap, I will determine the
> approximate break rate at full power which causes the RSG to start power
> arcing.  I will repeat with a 0.01 inch MOT air gap and see if the RSG can
> go slower before it power arcs.  This would indicate the reactor can indeed
> withstand more current through it without saturating.  Stay tuned for the
> next exciting episode . . .

    Eagerly anticipated.  Much thanks from us who are tossing around the
reactor idea.  I'll probably
be making one, since I have a large number of surplus Mots.
        --Mike