A 600 kVA, 1-ph transformer has an efficiency of 92 % both at full-load and half-load at unity power factor. Determine its efficiency at 60 % of full load at 0.8 power factor lag.

When the transformer is loaded in a balanced fashion up to its nominal rating (10 MVA), calculate the high side line-to-line phasor voltages (ab, bc, ca). and low side phasor voltages both line-to-line and line-to-neutral (ab, bc, ca, a, b,c). as a reference for calculations the low side A line to neutral voltage is 7620V at an angle of 0 degrees when the transformer is at rated power.  The transformer has the following characteristics: V: 138kV delta high side/ 13.2 kV wye low side 9% impedance X/R ratio of 20

A 1,000/200 V transformer takes 0.3 at p.f. of 0.2 on open circuit. Find the magnetising, and iron loss component of no- load primary current.

A 25 kVA, 2 kV(rms)/100 V(rms) single phase transformer is connected between a 120 V(rms) utility supply and a resistive load. The load current was measured to be 20 A(rms). i. Determine the active power of the load. ii. Determine the primary RMS current. iii. Determine the equivalent resistance of the transformer as seen by the utility supply.