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Old 5th Dec 2013, 12:26 am   #16
Wendymott
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Join Date: Jun 2013
Location: Huddersfield, West Yorkshire, UK.
Posts: 1,782
Default Re: Testing a transformer for shorted turns

Why has no one suggested the "Ringing" Method ? With TV line output transformers, yes I know they work at 16Khz, but the theory should still work. Take a capacitor (say 1uf) for experimental purposes. from the "Sweep Sawtooth output" from a scope to the "Top end" of the primary of the transformer, also attach the scope probe to this point. The ground of the scope to the other end of the primary winding. Use a GOOD known transformer to set the parameters. Set the sweep to about 2ms/cm, and adjust the display for a pulse on the left of screen and there should be a decaying sinewave, displayed. If you short any secondary the ringing will be severely damped. Now transfer this to the suspect transformer. If I have time tomorrow I will try this method and post the scope settings and cap value.
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Wendy Mott G8BZY
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