Question

A 25 kVA, 13,800/240 V distribution transformer has a full load efficiency of 97% at unity power factor, at which the core loss is 80% of the copper loss. The transformer operates over a 24-hour period as follows: 22.5 kW load, 0.9 power factor lagging for four hours; 12.5 kW load, unity power factor for two hours; 6.25 kW load, unity power factor for eight hours, and no load for ten hours. Find the all-day efficiency of the transformer.

Name: a 25 kva 13800240 v distribution transformer has full load efficiency of 97 at unity power factor at which the core loss is 80 of the copper loss the transformer operates over a 24 hour peri 97792
Uploaded: 2023-09-03T03:37:49-08:00
Duration: 2 min 22 s
Channel: Adi S
Description: a 25 kva 13800240 v distribution transformer has full load efficiency of 97 at unity power factor at which the core loss is 80 of the copper loss the transformer operates over a 24 hour peri 97792

          A 25 kVA, 13,800/240 V distribution transformer has a full load efficiency of 97% at unity power factor, at which the core loss is 80% of the copper loss. The transformer operates over a 24-hour period as follows: 22.5 kW load, 0.9 power factor lagging for four hours; 12.5 kW load, unity power factor for two hours; 6.25 kW load, unity power factor for eight hours, and no load for ten hours. Find the all-day efficiency of the transformer.

Added by Deborah T.

University Physics with Modern Physics

Hugh D. Young 14th Edition

Instant Answer

Solved by Expert Adi S

09/03/2023

Step 1

Calculate the copper loss and core loss at full load: Copper loss = (I^2)R = (25,000/13,800)^2 x R = 41.67 R Core loss = 0.8 x Copper loss = 33.33 R Show more…

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A 25 kVA, 13,800/240 V distribution transformer has a full load efficiency of 97% at unity power factor, at which the core loss is 80% of the copper loss. The transformer operates over a 24-hour period as follows: 22.5 kW load, 0.9 power factor lagging for four hours; 12.5 kW load, unity power factor for two hours; 6.25 kW load, unity power factor for eight hours, and no load for ten hours. Find the all-day efficiency of the transformer.