Transformers

A transformer is rated at 550 / 220 v. With the low voltage winding shorted, it requires 25 v across the 550 v winding to permit rated current through both windings of the transformer. Calculate the percent impedance.

The load of a certain transformer is reduced to 50%, the copper loss would become

A transformer has 4% resistance and 6% reactance drop. Find the voltage regulation at full-load unity power factor

A single phase transformer when supplied from 220V, 50 Hz has eddy current loss of 50W. If the transformer is connected to a voltage of 330V, 50Hz, the eddy current loss will be

A Y-∆ connected transformer has a turns ratio of 1:1. If the primary line current is 5 amperes, what is the secondary line current?

In a T-T connected transformer, if the terminal voltage in the primary side is 220 volts, what is the voltage across the teaser transformer?

A single-phase transformer is rated 110/440 V, 2.5 kVA. Leakage reactance measured from the low-tension side is 0.06 Ω. Determine the leakage reactance on the high-tension side in per unit.

Three units of 1:10 Transformers are connected in ∆/Y to supply a 3-phase load from a 400-v, 3-phase source. What is the line voltage on the load side?

A 10:1 ideal transformer has a load of 0.1μF on the secondary. What is the load capacitance, as referred to the primary?

A 50-kVA single-phase transformer has on full-load a copper loss of 560 watts and iron loss of 500 watts. Calculate the efficiency at 25% of full-load for a power factor of 0.8 lagging.

A power transformer rated 50MVA, 34.5kV/13.8 kV is connected wye-wye. What is the rated primary line current?

What will happen to the current of a transformer when the temperature of the transformers winding increases?

Transformers are used to change the value of the following EXCEPT

When a V-V system is converted into Δ-Δ system, increase in the capacity of the system is _____ percent.

The applied voltage in a transformer is increased by 50 % and frequency is reduced by 50 %. The maximum core flux density will become ______________.

A transformer has 4 % resistance and 6 % reactance drop. Find the voltage regulation at full-load 0.8 p.f. lagging.

A 13.8 kV/440 V, 50 kVA single-phase transformer has a leakage reactance of 300 ohms referred to the 13.8 kV side. Determine the per unit value of the leakage reactance on the low voltage base.

Compute for the core loss if the transformer consumes 75 watts when it is connected across a 240 v source and taking 1.4 A. The primary resistance is 0.25 Ω

The primary of transformer has 200 turns and is excited by a 240 v, 60 Hz source. What is the maximum value of the core flux?

Which is not a characteristic of an ideal transformer?