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Re: Transformers
In a message dated 96-07-27 23:18:15 EDT, you write:
>
>Fellow coilers,
>
>Thanks to everybodys' hints and advice, I'm hopelessly " hooked on coilin "
>now. (I heard the warnings about it being addictive, just didn't think it'd
>happen to me :o) Now it seems like every time I improve or add somethin', I
>get bigger and better sparks! I can take away a few gaps, and fiddle with
>the tune so I can draw 15" arcs to myself, or add gaps and crank up the
>variac till the arcs come out 3-4 feet (haven't felt them yet ;o)
>
> Anyway, my specs are:
> four 9K 60ma neons-
> four homemade caps total .066 mfd-(soon will get commercial cap)
> eight static gaps at .028"-
> pri. coil is 1/4" copper tube 13 turns saucer (best sparks at turn #6)
> sec. coil is 6" dia. 28" winding on 1/8" plexi tube
> torroid is 5" alum. duct, 26" diameter, 1" above top turn of secondary
> average strikes to ground about 30" but a few longer ones to air, maybe 36"
>
> What I want to know is, after running for about 10 minutes (really 1 or 2
>min. maximum,with cooling off in between firings) one of the neons started
>smoking pretty good with a tar smell (understandably). The case doesn't even
>get warm, nor do the terminals, but the primary cord does heat up a little
>(about 18 gauge power cord) So I'm afraid they will eventually fry. I
>understand this is not unusual for neons to burn up after enough such abuse
>:o) I just was wonderin' if there are other (better) xformers between neons
>and pole pigs, that would be better for tesla coil use? I'm not too sure I'm
>ready for pigs yet, but don't wanna keep buyin' neons either. Are there
>smaller pole pig type xformers that can be used with 120v input? When I see
>a pig that is 10KVA, that is 10,000 volts, but what kind of current rating
>are they? I know my neons will work great at 1/2 or even 1/4 line
>voltage...can I use a pole pig the same way? (lower input for lower output)
>Any info will be much appreciated! Thanks!
>
> Ken Cravens
>
Ken,
First, you will get the best performance when the primary is tapped out near
the last turn or two. You should adjust your capacitor and toroid size to
allow the primary to be used to its full potential.
About the transformer question - I would buy two or three used neon sign
transformers at a time and then one or two a week sometimes. After a couple
of months, I could have paid for a pole pig. Then I finally did. Haven't
had a transformer problem since, many others of course. Mine is 14,400 volts
at 5kva which should produce about 350 ma of current. You can easily get
twice this much current out of these for several minutes at a time without
hurting them a bit. You will need a large 220 volt variac and something like
a welder for current limiting to use a pole pig. All in all, going to a pole
pig solves a lot of power supply problems but it is quite expensive. l am
lucky compared to what I have heard some people pay for this stuff. I paid
$100 for the pole pig and the same for the variac. For a welder, I borrow
the one from work.
Ed Sonderman