New MMC has MASSIVE issues: root cause found

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Scott Hanson" <huil888@xxxxxxxxxxxx>

JT -

For your new MMC, you used TRW type X675 capacitors rated .022uF at 2kV.

TRW's capacitor business was bought out several years ago by ASC, who still
offer the X675 capacitors. If you look at ASC's datasheet for the X675
series caps

http://www.ascapacitor.com/PDF/x675.PDF

you will see that the .022uF units are rated for a peak current of only 3.8
amps!! No wonder they failed as soon as you applied power!

These caps are totally unsuitable for Tesla coil service, as your tank
circuit likely sees peak currents of at least 100 amps.

As so many people have suggested, throw these capacitors away and obtain
some Cornell-Dubilier type 942C film-foil caps. The .15uF 2kV parts have a
peak current rating of over 400 amps are are well-proven in Tesla coil
service.

Regards,
Scott Hanson

----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Tuesday, November 29, 2005 6:34 AM
Subject: New MMC has MASSIVE issues


> Original poster: "JT Bowles" <jasotb@xxxxxxxxxxx>
>
> Hi, remember me saying i am creating a new MMC, rated double my previous
cap?
>
> I did that!, and it is closer to matching my NST also.
>
> BUT HERES THE ISSUE:
> *If I look carefully I can see dielectric breakdown on 2 of 12
> capacitors, while in use
> *The Mylar heats up fast
> *My MMC randomly sparks from one capacitor to another. Sometimes it
> wont do this at all.
>
> HOW IS THIS POSSIBLE! when I had an 18KV rated MMC, and it gradually
> broke down. But when i inserted my new MMC, rated 36KV, the MMC began
> to degrade faster than my old one.
>
> HOW IS THIS POSSIBLE!!!!!?
>
> Wow, i just want a working MMC.
>
> Any solid ideas as to why this is happening, terry? It really is very
> dissappointing.
>
>
>
>
> >From: "Tesla list" <tesla@xxxxxxxxxx>
> >To: tesla@xxxxxxxxxx
> >Subject: Parting out 900 watt coil
> >Date: Mon, 28 Nov 2005 19:03:55 -0700
> >
> >Original poster: "Hooper, Christopher AZ"
<christopher.az.hooper@xxxxxxxxx>
> >
> >Good day great coilers,
> >
> >I am parting out this 900 watt spark gap coil and even the 60ma/15kv
> >transformer (less than 1 hour run time) @
> >http://users.cableaz.com/~chooper/800watt_1200.htm. The only item I am
> >not selling is the top load as Dave at D&M High voltage does not make
> >them anymore and they are rare. Terry Blake bought one on my plexy
> >primary and loved it. I have a lot of love and care into this coil from
> >the low pass filter to the tank to the secondary and just want what I
> >have in it. Why you ask, it is Steve Ward's fault, as he introduced me
> >to Solid State a few years ago and never run my spark gap coils any
> >more. Even the control panel is for sale as my next project is a 200 amp
> >x 240 volt DRSSTC and those CM6OO IGBT's are not cheap even on ebay.
> >Hope these parts can go to a loving home as they need a special place to
> >live.
> >
> >Rgs,
> >christopher
>
>