Winding resistance test of transformer

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Hey good morning everyone!

I was trying to figure out how to figure out how many amps do you push to the high side and low side of the xfmr. What formula do you use or how do you figure out.

Thank you

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I did a Megger webinar and as I recall they said you should use 10% of rated current, so that’s what I go with now.

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Hi
Injection is by DC and it shall not exceed 10% of rated current
You can do 1% or more but not exceeding 10% and make sure uou de magnatize the core after that

All the information avaliable at Cigre 445

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Per NETA ATS 2025 7.2.2.B.8: Measure the resistance of each winding at each tap connection. Test current not to exceed 10 percent rated current according to IEEE C57.152.

You can find the rated current on the nameplate of the transformer.

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You don’t “push” amps. The load determines secondary current, and the primary current is calculated from that using the turns ratio. For a power transformer, primary current = (secondary voltage × secondary current) / primary voltage.