Question

7. A transformer is rated at 75kVA, with a primary voltage of 32kV. When tested under "Full Load" condition, its copper loss is 870W and core loss is 320W. If an industrial load rated at 1500V with a pf = 0.76 is connected to the secondary, determine: a) The transformation ratio. b) Total power loss at "one-third load". c) Efficiency of the transformer at "one-third load". d) Primary and secondary currents at "one-third load".

Answer 1

A transformer is rated at 75kVA, with a primary voltage of 32 kv. When tested under full load condition its copper loss i l 1870 w, and core loss ń 320 w. If an industrial load rated at 1500 v with a pf = 0.75 is connected to the secondary, determine. a) the transformation ratio Solution transformation ratio = karena mereka = 32000 1500 = 21. 333 power loss at ļrd load. b) Total Solutioni Power loss at Ird load 3 = Core loss & Copper loss at 1 rd load = 320 + (5)*(870) 320 + 96.667 = 416.667 Watts. Scanned with CamScanner

Efficieny of the transformer at - red load. Solution : Poutput at ord load 'at hard load output at I od load + A Power loss at Ird load. - § *(75kVA) *0.76 ☆ * (75 kVA) *0.76 + (416.667) 19 000 19000 416.667 0.97854 = : 97.854 %, d) Primary and secondary currents at įrd board. 19000 - 1500 * 12, * 0.76 (3 rd load] 19000 .Se on fit cond) 1500 x 0.76 = 16.667 Amps. - - Pirae find load) In Cat 1 3rd load) k 16.667 21. 333 = 0.78125 Amps. co so Scanned with CamScanner