Magnetic Balance test used to find the distribution of Flux (Magnetic), Core Assembly Condition and defect in winding (If any).
It may check at HV Side or LV Side as per requirement/ site condition.
For Star Connection, apply the supply at U & N measure the values at V & N as well as W & N, then repeat the apply at V & N measure other two values, repeat it to apply at W & N.
For Delta connections, apply voltage must be in Phase - Phase like U & V, V & W and W & U.
For Ex:
U & N = (V & N) + (W & N); 240 = 198 + 42
Example : Results of 16 MVA, 110/ 33 KV Transformer, Vector Group of Dyn 11 (Delta Star 11)
Magnetic Balance at HV side
1U - 1V 1V - 1W 1W - 1U
417.0 (Appl) 401.0 22.0
232.0 419.0 (Appl) 189.0
20.0 402 420 (Appl)
Magnetic Balance at LV Side:
2u - 2n 2v - 2n 2w - 2n
238 (App) 208 31
122 241 (App) 119
38 207 245 (App)
Nice
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