Re: strange variac

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com> 


Some variacs vary, but usually the 120 VAC input is placed across terminals
1 & 4.  Output is terminal 3.  Check with voltmeter between 3 and 4 to
determine correct 120 VAC output.  Sometimes the hot is on 4 and common
(neutral) is 1, and other times the hot and netrual are reversed, ie, hot on
1 and common on 4.

Dr. Resonance

 >
 > This is my first time attempting to post anything, so please bare with
 > me.  At any rate, I am in the process of building my first coil and at a
 > recent Ham-fest, I picked up a variac that looked as though it was in
 > excellent shape (good brush, easy rotation, no burnt windings).  Anyways,
I
 > have come to find out that I cannot find any litterature anywhere about
the
 > terminal assignments for this thing(except for the brush on T-3).  It is a
 > Staco Adjust-a-Volt with the following characteristics:
 > Type: 500 BU
 > Rated Current:  7.5A
 > Input V: 120V 50/60Hz
 > Output V: 0-140V
 > Additionally, it has 7 terminals to choose from(That is the real source
for
 > my confusion).
 >
 > The first time I hooked it up with the common on T-4 and hot on T-5, I got
 > 140V at max scale between common and brush.
 > The second time, I used T-4 for common and T-6 for hot and tripped the
 > circuit breaker.
 > Then, I changed it back to T-4 and T-5 and was checking the current into
it
 > with my meter in series.  It was not drawing much current in a steady
state
 > senario, but once I hit the terminal and backed of and hit it again and a
 > nice spark roasted my fine point of my meter into a flat.  Is this the
 > effect of "inrush current?" (BTW, it was still operating at the prescribed
 > 140V out at max on the scale.)
 > Also, if anybody knows anything about this crazy variac.  How do I hook it
 > up to get 120V max output for my NST?
 > I cannot find anything from Staco's site that says that this thing ever
 > existed, so any help will be greatly appreciated.
 >
 > Thanks,
 > Andy
 >
 >
 >