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Re: I need a bigger variac. (fwd)
---------- Forwarded message ----------
Date: Wed, 17 Dec 97 17:39:11 -0500
From: Adam <absmith-at-tiac-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: I need a bigger variac. (fwd)
>> I know that these can be purchased at hamfests, but there aren't any in
>> Boston in winter as far as I know, and I need the variac like, yesterday.
>> This is the only thing that keeps me from firing up to full power today.
>> Surplus catalogs that I've got have these for about $300+, but I know
>> that when I was last at the Rochester Hamfest these were selling for
>> around $20-$30. Huge difference.
>Your transformers should draw about 5 amps each for a total of 10 amps. Your
>present variac should be able to handle that without getting too hot.
>This is providing you are using power factor correction caps across the
primary of
>the transformers. Without pfc caps, the total input current may be 15 amps or
>more, which is too much for your variac.
>
>Ed Sonderman
If the PFC caps will help extend the small variac's range, it's certainly
worth a try! Mostly I was looking for a new variac so that I can add
another transformer to the project stack for a total of 9kV -at- 180mA, and
I can use the small variac for my spark gap fan speed control. I was
using no PFC caps with the two transformers, and the variac was growling
and blowing the 10A fuse when I cranked it up to 140V. I'll buy some
caps.
In the time elapsed since I sent that post, a lengthy search through the
ham radio usenet groups has scored me an 18amp powerstat for $35. I
almost overlooked those groups entirely.
So this subject is now resolved, thanks.
-Adam
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absmith-at-tiac-dot-net
Epoch, Inc. Digital Music Project
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