Inductance in Transformers inductors


How can I find a transformers inductors value by using the derivative formula? If I want to generate high voltage spikes from a square wave generator of 10V p-p with a source resistance of 50Ω. I want 25V peak from my spikes.

Thank you.

Best Answer

We'll you can't really uncover the inductance value of an unknown winding by just knowing a formula. The normal tests to do this are an open secondary test and a shorted secondary test.

The open circuit test requires a measurement of primary current for an applied voltage. The impedance calculated from V and I is usually regarded as indicative of the primary mag inductance.

A short circuit secondary test with a smaller input voltage whilst measuring the primary current will reasonably hint at the leakage inductance of both windings together. Then, knowing the transformer turns ratio, you can start to put leakage inductance values on the primary and secondary.

If it's a HF transformer you need to adopt a different approach that measures resonant frequencies of the primary and secondary and, because leakage capacitance is significantly more dominant now, it's a bit trickier doing the estimations.