Re: MOT Caps DC Limit

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Chris Rutherford" <chris1@xxxxxxxxxxxxxxxxxxx>

Hi All,

Having just tried a few experiments with a 50ma 10KV NST, it turns out that 
MMOCs don't work unless they are bridge rectified.  The losses must be too 
great for any significant charge to be built up in the first place.  The 
only way I could get any spark was by tying a piece of wire to the end of a 
nylon pole and 'helping' my RSG.

They work fine in a DC voltage multiplier configuration using a MOT, and 
with an inductive charger they work very well as a Tesla DC PSU.  I have 
used 4 * 2400AC capacitors in series with 11KV (2000AC multiplied by 4 
using diodes) across them with no problems (so far).

My only problem is getting hold of a HV inductive charger that lasts for 
more than 5 minutes.  The words self, wound and core spring to mind. :-) 
But 40 Henries is an awful lot of winding using well insulated wire... Any 
ideas?

Thanks

Chris

----- Original Message ----- From: "Chris Rutherford" 
<chris1@xxxxxxxxxxxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Sunday, July 17, 2005 11:52 AM
Subject: Re: MOT Caps DC Limit


> Hi Ted,
>
> I'm looking to build a MMOC (Multiple Microwave Oven Capacitor).  Here is 
> a useful site vie found: -
>
> http://www.capacitorindustries.com/PFC/microwave.htm
>
> Some coilers recommend removing the solder oil seal to allow for pressure 
> equalisation during in heating, and placing the whole capacitor string in 
> a oil tub.
>
> Today I'm going to perform some experiments (outside!) to see what a 
> string of 10 x1.3uF MO capacitors can withstand.
>
> 1st NST short circuit across string, measure temp rise of capacitor case.
>
> 2nd RSG 100BPS, small inductance, measure temp rise.
>
> Thanks
>
> Chris
>
>
> ----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
> To: <tesla@xxxxxxxxxx>
> Sent: Sunday, July 17, 2005 6:29 AM
> Subject: MOT Caps DC Limit
>
>
> > Original poster: tesla <tesla@xxxxxxxxxxxxxxx>
> >
> > Team
> > I'm looking to use MOT caps rated around 2300v AC as DC filter caps for a DC
> > based coil.
> > You would not believe how hard it is to find  HV caps in NZ of 3uF to 6uF
> > 10kv wkg. 5 Yrs ago a glut as old high power TV and MF xmitters changed to
> > SS. Mostly dumped or sent back to mfr ( due pcb's)
> >
> > One that I have notes its Test Voltage was 10kv.
> >
> > Has anybody experience with just how far I can take a MOT cap in DC filter
> > service. My guess is about 6kV DC for short period (1 min or so) is probably
> > OK
> >
> > FWIW The system is to be 3 MOTS per side rectified for Plus and minus 8kV
> > into 50 Hy or so and ASRSG up to 200bps with 90nF of Tank Cap
> > Tnx
> > Ted L in NZ