Transformers

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Paulson

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I am looking for a formula that will calculate the voltage and current for a transformer with multiple winding primary and a multiple winding secondary.

I haven't been able to find anything up to this point
 
Vin/Vout ~ # of primary turns/# of secondary turns.

For an existing transformer, if you can
get a peek at the wire size used in winding, and
measure the winding resistance, and
measure the volume of the winding,
you could, in principle, figure out how many turns there are.

Do this with each winding and then use the formula above.

The number of turns in the primary is determined by the desired flux density in the core. Done by hand, transformer design is not all that easy. It's all non-linear.
 
Maybe I didn't understand your question.
The power levels that a transformer of a given size can handle can be estimated from a transformer catalog. Use the stated power level and dimensions and plot volume vs. power.
Ideally you should plot this on whatever kind of scales (log, linear, reciprocal, etc.) give you a straight line.
 
Here's my problem. I have a transformer with two 120 vac primary windings and two 30 vac secondary windings. If I apply 120 vac to one of the primary windings and short the other primary winding what do I get on the secondary windings. Also the transformer is constructed such that shorting a primary winding does not blow the primary fuses.
 
I have a transformer with two 120 vac primary windings and two 30 vac secondary windings. If I apply 120 vac to one of the primary windings and short the other primary winding what do I get on the secondary windings.

>Back in school, you had to draw the equivalent circuit of the transformer and then calculate this.
>I'd try it and measure it, though I don't know why you would want to short it. Don't leave the short on very long.
>I'd think this transformer is meant to run on 120v or 240v, and the secondaries can put out 30v at high current (windings paralleled) or 60v at lower current.
>This is a versatile transformer. If you parallel windings be sure they are phased correctly.

Also the transformer is constructed such that shorting a primary winding does not blow the primary fuses.

>Some transformers, like doorbell transformers, are constructed magnetically so they shut down if shorted, rather than putting out high current. These kinds of transformers are bulky for the amount of VA they deliver.
 
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