# how to find series inductance of a transformer

I'm designing feedback loop compensator for inverter. here i have H bridge, output transformer and output capacitor. it is just like dc dc converter for inverter so i needed to know How to calculate series inductance of a transformer

• What is your numerical or technical starting point? Mar 16 '16 at 14:46
• i did not get you Mr. andy
– krs
Mar 17 '16 at 4:01
• What inductance do you need. What current is it rated at. These are numbers. Mar 17 '16 at 8:01
• transformer is 1:33, input is PWM unipolar pulse, current rating is 80A for 1kVA transformer, input is about 7.5V and output is 230V(aprox.)
– krs
Mar 17 '16 at 9:14
– krs
Mar 18 '16 at 10:09

Steps

1. What you have to know is the transformer rating.
2. Let's say the current rating is 10A for example.
3. short circuit the secondary but measure the current through the short.
4. You will need a phase angle meter such as an Arbiter 928A
5. Energize the primary with a voltage source being careful not to exceed the 10 amps on the secondary
6. Put the voltage channel A of the arbiter across the voltage element and measure the current using channel B of the arbiter. The arbiter will show the current with a positive lag angle theta by default. Say we get 45 degrees. This means that the voltage on channel A is 0 degrees and the current on channel B is 360-45=315 degrees. Say it took 10 volts to do this and the current in the primary is 2 amps. Z = 10 < 0 degrees / 2 < -45 degrees = 5 ohms < 45 degrees.

Theory

Z = V/I, its the LAW!!

Where I = the current through the primary. Where V = the voltage across the primary. simulate this circuit – Schematic created using CircuitLab