Transformer MCQ Questions and Answers

381. Open circuit test on transformer is used to find

1. No-load current
2. Full load copper loss
3. Equivalent resistance referred to metering side
4. Equivalent resistance referred to metering side and no-load current both

382. Transformers can be connected in

1. Both series and parallel
2. Series
3. Parallel
4. Neither series nor parallel

383. In a transformer on load the total primary current is given by

1. Load component of secondary current
2. Sum of magnetizing current and reflected load current on the primary side
3. Reflected load current on the primary side
4. Magnetizing current

384. The efficiency of a transformer depends

1. On both power factor and load magnitude
2. On load power factor
3. On load magnitude
4. Neither on load power factor nor on load magnitude

385. The no-load primary current will be approximately in the range of ________ time the rated load current in a transformer.

1. 0.8
2. 0.1
3. 0.9
4. 0.5

386. Transformers _______ Reactive power.

1. Generate
2. Neither generate nor absorb
3. Absorb
4. Absorb as well as generate

387. The short circuit test in a transformer is carried out by solidly shorting

1. Only high voltage windings
2. Only low voltage windings
3. Either high voltage and low voltage windings
4. Both high voltage and low voltage windings

388. The frequency affects

1. Both hysteresis and eddy current loss
2. Only eddy current loss
3. Neither hysteresis nor eddy current loss
4. Only hysteresis loss

389. The flux density affects

1. Neither hysteresis nor eddy current loss
2. Only eddy current loss
3. Only core loss
4. Only hysteresis loss

390. A transformer is equivalent to an ideal transformer

1. With inductive coil connected in the secondary circuit
2. When no coils are connected to primary and secondary
3. With inductive coil connected in only the primary circuit
4. With inductive coils connected in both the primary and secondary circuits

391. In a transformer the leakage flux

1. Contributes to transfer of energy from primary to secondary
2. Does not contribute to transfer of energy from primary to secondary
3. Contributes to transfer of energy from secondary to primary
4. Contributes to transfer of energy between both coils simulataneously

392. The sheet steel material used in transformer core has

1. High core loss and low permeability
2. Low core loss and low permeability
3. Low core loss and high permeability
4. High core loss and high permeability

393. Booster tranformers are used to

1. To change the voltage magnitude and phase angle
2. Reduce the voltage magnitude
3. Increase the voltage magnitude
4. To change phase angle

394. Regulation of a transformer is defined by rise in primary voltage required to maintain rated output voltage at a given power factor for a lagging power factor load

1. From no load to 50% of full load
2. From no load to full load
3. From no load to 25% of full load
4. From no load to 75% of full load

395. The short circuit test in a transformer is carried out

1. At full load current
2. At half load current
3. At very small load current
4. At greater than full load current

396. An exact equivalent circuit of a transformer is given by

1. Conductance and susceptance for mutual flux
2. Resistance and inductance for primary & secondary windings and conductance and susceptance to represent the mutual flux
3. Resistance and inductance for primary and secondary windings respectively
4. Resistance and inductance for primary , secondary and mutual flux linkages respectively

397. The no load primary input is approximately equal to the

1. Iron loss of transformer
2. Sum of iron loss and copper loss of transformer
3. Neither iron loss of transformer nor copper loss
4. Copper loss of transformer