Answer / guest

1. Insulation Resistance Measurement
a . For LT systems, use only 500V or 1000V Megger
b. For MV & HV systems, use 2500V or 5000V Megger
c. Remove Earth from Transformer neutral
2. Winding Resistance Measurement
R-N AND r-n
Y-N y-n
B-N b-n
3. Magnetic Current Test
Applied Voltage : RY YB BR
Measured Current : R Y B
4. Magnetic Balance Test
5. Vector Group Confirmation.
6 . Short Circuit Test and Differential Stability.
7 . REF Stability Test
8. Cooler Circuits.
9. Auxilliary Protection Circuits

Answer / brahma

Also Double voltage double frequency, if customer ask impulse

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