You do not know the secondary voltage, so anything you do is guesswork. You
can try the following:
If you have another transformer that puts out 10 or so volts, connect the
secondary of the unknown transformer to the 10 volts and measure the primary
voltage. If it is reasonable (120 volts or so), attach a 25 watt 120 volt
light bulb to the primary to see if it will work.
Well, if you are just trying to determine the turns ratio, then you connect
your 10 volts from the KNOWN transformer to what you hope and believe in the
PRIMARY. You expect about 1 volt out.
To a first approximation the DC resistance is in proportion to the SQUARE of
the turns ratio. The higher voltage winding should have MUCH higher DC
resistance. (Note that I didn't say the PRIMARY had higher DC resistance.
It is quite possible that your transformer was designed as a step UP
Without having the manufactures specifications or data there is not much you
can do other than do a simple continuity check of the primary and secondary
winding(s). The continuity test however will not tell you if any of the
windings are shorted.
Without manufacturer's specs you cannot tell, because what matters is
impedence (micoHenrys?) not ohms. For example I connected an ohm meter to
the AC side of a power brick rated 120V~0.3A 60Hz and it measured .000
ohms, but it works fine. So you cannot necessarily tell with an ohm meter
if there is a short, only if there is no connection at all.
PS: you forgot to tell us its output rating.
David Efflandt - All spam ignored http://www.de-srv.com /
http://www.autox.chicago.il.us/ http://www.berniesfloral.net /
Thanks to all who responded to my question.
The transformer is used in a circular flourescent lamp-magnifying glass
combo that is about 40 or so years old.
The lamp does not light up and the bulb has been checked OK. That leaves the
switch (a special switch for flourescent lighting) and the transformer
suspect. I guessing that the transformer acts as the ballast for the bulb
but I may be wrong. I believe that the output of the transformer is 22
I'm trying to repair this lamp for an individual that is losing his sight.
<snip quoted message incorrectly placed at bottom>
It's not a transformer, it's a ballast.
By "special switch", do you mean the starter, which is typically a small
cylindrical object which fits into a socket, approximately 2cm in diameter
by 4cm long.
Does anything happen when you turn the light on?
http://inquisitor.i.am/ | mailto: firstname.lastname@example.org | Ian Stirling.
It is not the typical starter switch that you describe as a cylindrical
The manufacturer's name on the switch is Gaynor-Andrews of Bridgeport, CT.
I did a "Google" and found a Edwin Gaynor Corp.in Stratford, CT.
If you go to www.egaynor.com/wd1170.htm , you will find a similar type of
switch except for the fact that the old one is a two button switch versus
the new one is a rocker. These are made expressly for flourescent lighting.
I'm going to contact the manufacturer and see if they can help me. Thank you
for your interest.
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