Re: MOT Caps DC Limit

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Paul Benham" <paulb@xxxxxxxxxxxxxxxxxxxx>

Hi Ted,



> Original poster: tesla@xxxxxxxxxxxxxxx
> Unclear about your ref to needing to be bridge rectified.

> I am extrapolating that if 2 MOT's secondaries in series as inductors on a
> smaller coil can take the back EMF of a fully charged inductor field
collapse
> then 3 in series (well isolated from each other and gnd) should be OK in a
> bigger coil.

I was using two MOT secondaries as my resonant charging choke in parallel
with another two in series.  With approximately 10kV DC feeding the choke
one of them eventually flashed over.  I then went to three in series in
parallel with three in series.

> I'm most impressed and the smooth current draw and easy control of power
these
> designs offer and want to convert my 6MOT stack AC SRSG design to a
> DC resonant
> charge system.
>
> Rgds
> Ted in NZ

I thought this too.  I set mine up so I could run almost 6kW at 600bps.  So
the resulting reactor value was not very large.  The higher the maximum BPS
you want run, the lower the value of the reactor needed.  However when I ran
near to the lower end of the BPS range, I'm guessing around 100BPS, the
rotary dwell time increased to the point where the current in the charging
reactor was getting too high during this time.  The power supply was unable
to provide the current and I was discharging the power supply capacitors.
The current in the gap ended up high enough for the arc to follow round
which was bad.

I am now re-configuring my setup so it will only fully charge the capacitor
at a maximum BPS of 200-300.  I will run it at a higher BPS than this, but
knowing that the capacitor will not get fully charged.  Also I am removing
four of my electrodes from my rotary and running it twice as fast to reduce
down the dwell time.  To get back to my 6kW maximum I am going to increase
the value of the primary capacitor.

So although the theory says you can run any BPS, in practice I found that
there is a lower limit depending on the value of the charging reactor and
dwell time of the rotary.

Cheers,

Paul.



This message has been scanned for viruses by MailController - 
www.MailController.altohiway.com