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Re: multiple gap question
In <4.1.20000212132139.009f1100-at-pop.dnvr.uswest-dot-net>, on 02/13/00
at 05:22 PM, Tesla List <tesla-at-pupman-dot-com> said:
>Original Poster: "Ed Phillips" <evp-at-pacbell-dot-net>
>> I haven't built an in - line gap like that but I have built a RQ style gap.
>> I used one length of copper pipe and cut it into sections with a large
copper
>> tubing cutter. This left the ends slightly rolled in and made the diameter
<snip>
> How would you keep the nylon from melting? For that matter, I've always
>wondered about the PVC-supported gaps. Do the cooling fans really cool
>enough to keep the stuff from melting?
>Ed
I was having problems with the gaps overheating a few years ago. Without
any air cooling the 1/4" plexiglass would bend over and either short out
or open the gap and quit firing depending on which way it decided to bend.
Then I would have to lay it down and force it back into as flat a shape as
I could. So I built a box out of plywood and placed the gap on one end. A
vacuum motor was placed over a hole in the top of the box. The only room
on the table forced me to stand it on end with the gaps facing the roof.
Same thing would happen with this huge amount of air cooling. It still
bent in the middle causing me to shutdown, only it did last a few minutes
longer before sagging.
One of my RQ-gaps has scorch marks where the tubes touch the sides and
also on the inner piece of pvc used for an air block. I don't use either
of these anymore. I have a bigger RQ-gap, but it doesn't get much run-time
since I built a sync-gap. This gap has 1/2" plexiglass for a rotor. Yeah,
I know it isn't a good choice, but it is thick and only spins at 1800rpm.
It doesn't get hot, a little warm maybe.
If I were going to use a static-gap, it would have to have something other
than plastic supporting the electrodes.
Alan