[HomeBrew] Variac Transformer 100L

[Ian Fulton]

Hi Richard

Just refurbished one about six months ago but was for another amateur

The transformer is not isolated so careful where you touch it, think of it
as a mains coil with an adjustable tap.

It is very dusty and may need the top of the variac coil and brushes
cleaning but try it first before taking it to bits in the old adage if it
works leave it alone.

The two bottom connecters should be common and possibly connected, connect
your mains to the left hand side and switch on making sure you have a fuse
in line with the Variac and make sure the LIVE is on the proper terminal and
not on the common terminal. You should hear a thump and then humming from
the Variac when you switch on which is common. 

Put a voltmeter between the two terminals on the right. When the knob
pointer is fully anti clockwise there should be minimum voltage.

If you are happy that the Variac is working properly, then connect to your
rig and gradually increase the voltage in a period of about a week to make
sure your capacitors are reinvigorated.

73's

Ian G4XFC
www.g5fz.co.uk



-----Original Message-----
From: homebrew-bounces at mailman.qth.net
[mailto:homebrew-bounces at mailman.qth.net] On Behalf Of R. Blackman
Sent: 13 December 2010 03:13
To: HOMEBREW
Subject: [HomeBrew] Variac Transformer 100L

** Please do NOT cross-post messages when posting to HOMEBREW **

Hello to group and a happy holiday season to all.

I have a very old boatanchor radio that I would like to bring up on a
borrowed variac transformer.
I have no experience with variacs, this one is old and dusty, a web Google
gave me little information on it.

Photos of the variac are here:
http://picasaweb.google.com/blackman.richard/Variac100L#

There are six connection points, some unlabeled. The 115 and 230 are
obvious.

1)  is there a way to safely test this variac first without powering  it up?
And while on the 'powering up' subject:

2) can anyone give me some guidance on the connections so I don't blow
things up 'real good'?

3) after properly connected, what is the proper procedure for use?
For example: how slowly do you raise the voltage?

Many thanks

Richard VA3NDO 

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