Cheap LCR meter to measure leakage inductance in transformer?

[grizedale]

Hello,

Is it ok to use a cheap standard LCR meter to measure leakage inductance of a switch mode transformer?

The transformer is for use in a 250W half bridge converter with vin = 90vac to 265vac.

-there is no PFC stage as its not required for our audio application.

The outputs are +-50V, -each at 130W, and 16V at 6W.

 

[mtwieg]

Depends on what kind of leakages you're talking about. For measuring several uH or more a DMM with an LCR function might be good. But anything less than a couple uH will require a good benchtop LCR meter with kelvin sense leads, and a high measurement frequency. I own an old stanford research SR715 LCR meter which is pretty good (measures up to 10KHz), but a LCR720 (100KHz) would be much better. They show up on ebay occasionally for 150-400USD.

 

[grizedale]

Hi,


The converter will run at 11KHz, is it important to measure leakage using this frequency?

 

[mtwieg]

No, leakage inductance shouldn't change with frequency, unless you go way up in frequency near the resonance of the transformer.