The core loss of a 5KVA single phase transformer with normal voltage applied to the primary is 74 watts. The maximum efficiency occurs at 70% of full-load KVA. What is the full load efficiency of the transformer at untiy power factor?

An 10000/100V, 50 Hz, single phase transformer has an exciting current of 0.8 A and a core loss of 400 W when its HV side is energized at rated voltage. The core loss component of the existing current is ?

Power transformers are designed to have maximum efficiency at

If a transformer have turn ratio 5, frequency 50 Hz, root mean square value of potential difference on primary winding is 100 volts and the resistance of the secondary winding is 500  then the peak value of voltage in secondary winding will be (the efficiency of the transformer is hundred percent)-

The no-load current drawn by the transformer is usually what percent of the full-load current ? (a) 0.2 to 0.5 per cent (b) 2 to 5 per cent (c) 12 to 15 percent (

A single Phase 50kVA, 2400/240V, 60Hz distribution transformer is used as a step downtransformer at the load end of a 2400V feeder whose series impedance is (1.0 + j2.0) ohms. Theequivalent series impedance of the transformer is (1.0 + j2.5) ohms referred to the high voltage (i.e.primary) side. The transformer is delivering rated total power at 0.8 power factor lagging, and atrated secondary voltage. Neglecting the transformer excitation current, determine:(a) The voltage at the transformer primary terminals,(b) The voltage at the sending end of the feeder,(c) The real and reactive power delivered to the sending end of the feeder.Work in the Per Unit System, using the transformer ratings as base quantities