[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Build own capacators
Original poster: "James Zimmerschied" <zimtesla@xxxxxxx>
Hello Terry and others on the List,
Some discussions about home built oil capacitors and performance:
I tried a little experiment with a small coil running a 30 ma NST. I
tuned the coil to run on 0.009 microF CD 942 MMC and observed the
streamers. Then I tried two 0.018 microF rolled poly oil caps in
series (0.009 microF). I retuned slightly to get the best output. The
streamers were very similar in length and color. Then I tried a
series set of barium titanate ceramic caps which I borrowed. These
were also 0.009 microF. The streamers were again about the same. As a
final test I used a 0.009 microF MMC made up of mica caps (2500 VDC
0.01microF). These gave less spark length than the other types I
tried (11" vs 16").
I also put a small incandescent bulb's filament in series with the
coil's secondary at the ground end to observe current draw in the
secondary. In this test, the rolled poly and mica caps produced the
most current (i.e. brightest glow in the bulb filament). Next was the
barium titanate and last was the CD MMC. It is not clear to me why
the CD MMC and the rolled poly produced similar arc quality when the
bulb indicates the power to the streamers was higher with the rolled
poly caps? Also puzzling is why the mica caps performance was low
when the power in the secondary was at least as high as the rolled
poly caps based on filament glow.
The conclusion I reached was that any of these types of caps (except
maybe the mica caps) would be good for this size of coil. The rolled
poly caps certainly equaled the CD MMC in performance at the expense
of being bulky and an oil spill hazard.
Jim Zimmerschied
----- Original Message -----
From: <mailto:tesla@xxxxxxxxxx>Tesla list
To: <mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx
Sent: Friday, December 16, 2005 5:47 PM
Subject: Re: Build own capacators
Original poster: Terry Fritz
<<mailto:vardin@xxxxxxxxxxxxxxxxxxxxxxx>vardin@twfpowerelectronicscom>
Hi Dave,
At 06:08 PM 12/16/2005, you wrote:
snip>
I don't think an MMC will perform noticeably better than a nice
rolled cap. They are both "so good" electrically that I think any
difference would not be very noticeable between them. Of course MMCs
have other nice advantages. But if you looking for better
performance only, the MMC should not matter.
Cheers,
Terry