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Re: [TCML] why do variacs cost so much?
Has anyone considered using what I know as a "buck and boost circuit" to increase the effective power a Variac can handle?.
If you take a large ordinary transformer, with say a 50 volt secondary, the variac is connected to the primary of the transformer and is wired so that it can apply full line volts in either phase using the centre tap of the variac. The output of the large transformer is therefore varying 50 - 0 - 50
By adjusting the Variac, 50 volts can be subtracted or added to the line voltage if the transformer secondary is in series with the line supply.
The advantage of doing this is that the Variac doesn't handle the full power of the supply. The disadvantage is you heed another transformer and the lowest setting isn't zero volts
If the Variac doesn't have a centre tap, you could still use the circuit to add some antiphase volts to the line supply
Clive
________________________________
From: Co60bishop <co60bishop@xxxxxxx>
To: tesla@xxxxxxxxxx
Sent: Thursday, 12 July 2012, 2:25
Subject: Re: [TCML] why do variacs cost so much?
I have a 180 to 250 VAC 5.5 KVA 24 Amp one. Unfortunately you are looking for one twice that size.
Allen
-----Original Message-----
From: Neon Tesla <neontesla@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Wed, Jul 11, 2012 6:16 pm
Subject: Re: [TCML] why do variacs cost so much?
We then I'm out of luck because I need a 240V 50A
ariac, or perhaps a slide choke of there about.
-
Don't lower your expectations, raise the voltage !*
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