Hello James,
First of all, I recommend staying away from the ultra-cheap Chinese ones like this:
https://www.circuitspecialists.com/content/451335/tdgc2-2d-0.jpg
I know that it may be tempting to go for it simply because it's ridiculously cheap (for a variac), but usually if the price seems too good to be true, it is.These cheap Chinese-made ones have an extremely poor build quality and are known to fail very easily and frequently - the windings and contacts melt, causing irreparable damage and even safety hazards. Generally speaking, your best option is to look for older models. You might try Ebay, though shipping will probably be an issue due to the weight. Also check Craigslist or even Facebook Marketplace. You can sometimes find some gems there. Same with swap meets or hamfests. Also check with your local university, though I have never had much luck with this option. Then again, I live up in the sticks so there's really not a whole lot up here anyway....
Be mindful of the current rating of the Variac. While they can normally handle large surges (~10x their rated current) for very short periods of time, they should not be left connected to a load which draws above the rated current for an extended period of time. This can cause overheating and permanent damage to the windings and/or brushes. Choose one with a current rating that will be suitable for your application. Also be aware that if you buy one rated for higher than 15 amps, a standard household outlet will not be able to handle it.
Just a few tips to get you started.
Best,
Matt Lewis, Fairlee VT
-----Original Message-----
From: James Janota via Tesla <tesla@xxxxxxxxxx>
To: tesla <tesla@xxxxxxxxxx>
Sent: Wed, Aug 14, 2019 7:36 pm
Subject: [TCML] Variac choices.
I was looking at various Variac models and kind of concerned about what I should be looking at. Any advice from you all would be appreciated.
Regards
James Janota
(727)512-7112 Phone
(727)595-6625 Fax
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