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Re: First Light!!! Now, how to tune it?
Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
At 10:42 PM 5/12/2001 -0400, you wrote:
>Tesla list wrote:
>> Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
>> 15/180 resonant size is 31.83nF and LTR is 45nF. With 60nF I think you
>> will hit a 60Hz charge BPS which probably is not too bad. You should use
>> input line fuses to each transformer. With such a large cap, the shunts
>> may saturate and it could draw a lot of current. Maybe a 15 amp fuse per
>> NST. However, this is far less a problem with a static gap design. You
>> should consider getting one more 15/60 NST :-)) You may also want to add
>> about 150uF of power factor correction to each NST. That will drop the
>> current to each NST about 6 amps for a total of 18 amps less current draw
>> which is a big deal in this case.
>Can you recommend a particular PFC cap? Maybe something from digikey?
A number of people have mentioned surplus ones for a very good price. I
use 20uF ones from DigiKey but they are like $6 each. Good for
experimental work to get any value but too expensive considering they can
be had in large values for a few dollars on the surplus market. I forget
the places that have them right off but look in the archives.
>I did pop the house line breaker a couple of times. Is this a serious
>problem? If so, I'll put fuses on the NST's. Can breakers be used
>instead of fuses, if only so as not to have to replace fuses?
Breakers are fine. The PFC caps may help prevent the house circuit
breakers from tripping.
>> >Toroid: 6" aluminum dryer duct wrapped around an 8" diameter disk
>> >(actually two aluminum pie
>> >pans). Used a thumbtack as a breakout point, but there were streamers
>> >coming out all over (is that a good sign?).
>> 6 inch cord with 14 inch center to center spacing...
>> >Toroid? Does it need to be bigger? How big?
>> It does strike me as small for 2700 Watts input. You will get smaller
>> multiple streamers instead of a longer single streamer. But that is cool
>> too so what ever you like.
>I'll probably make another, maybe a double toroid. The pie pans work
>real well - very easy construction - but they only come so big.
Get Pizza pans from K-Mart or whatever. Mine are 16 inches in diameter.
The stainless steel ones are cheaper than the aluminum ones here.
>Another question: I have my NST's mounted on a cart, and they sit
>alongside the coil during operation. Should I be concerned about
>strikes to the power supply? I thought about putting some grounded
>chicken wire over the supply to catch strikes; would that help?
Streamers don't have a lot of current but it is hard to say. I have done
fault studies that suggest there is little danger but a grounded wire sure
seems like a great idea.
>Thanks again for the help.
> - Bill Vanyo