MMC Caps - more tests and last UK orders please.


I've just tried out a string of the RS 0.047uF caps
in parallel with my 0.067uF cap.

Coil 200kHz, 8kV 250mA transformer.

ran fine with 6, 5 and even just 4 in series - these
caps are only rated for 1500V DC each! I didn't have
the courage to try 3, Ritchie has done some destructive
testing - they blew at about 3KV AC from memory.

I then took out my old caps and put in an array of
5 strings of 6 caps - all 0.047uF, mixture of Farnell
and RS equivalents.

(The Farnell ones have a slightly smaller diameter
and are rated for 2000V/uS.
The RS ones seem slightly better made and are
rated for 1800V/uS. - they are also cheaper -
Farnell doesn't give a further price at 1000+)

I was well impressed by the results - I was getting
bigger and better arcs with 0.04uF total capacitance
than I had been getting with 0.09uF in the old caps.

Run times have to be limited in the garage - not
enough room for the arcs - and even with the doors
open - I prefer to limit my exposure to ozone.

The caps were barely perceptably warm after a few
short runs.

I'm now keen to finish these caps - I'll be using 9
in series in the final caps - which will give a fair
safety margin.

Thanks to those who have expressed an interest in
the UK bulk order - I think that we are up to
about 1100  on the indications of interest so far,
I intend to order by the weekend. I can't really take many
more orders as the outlay is will be a bit steep for me.

Please if anyone out there has found a better cap
cheaper in the UK speak now or forever hold your peace.
(sorry thats my Saturday job coming out)

Have fun,

Alan Sharp (UK)