Which transformer is used to trap the harmonics on the primary windings?

Which transformer is used to trap the harmonics on the primary windings?

a) k-type transformer
b) core type transformer
c) potential transformer
d) shell type transformer
e) Autotransformer




Answer: A

Double-wound transformers can be connected as?

Double-wound transformers can be connected as?

a) current transformer
b) core type transformer
c) potential transformer
d) shell type transformer
e) Autotransformer





Answer: E

Iron loses in a transformer are caused by?

Iron loses in a transformer are caused by?

a. Eddy currents
b. Magnetic hysteresis
c. Harmonic distortion
d. All of the above
e. A and B




Answer: E

All of the primary and secondary is wound on the centre leg. This transformer is called?

All of the primary and secondary is wound on the centre leg. This transformer is called?

a) current transformer
b) core type transformer
c) potential transformer
d) shell type transformer
e) resistance indicator





Answer: D

Primary and secondary windings are split into two equal parts, with one half of the primary and one half of the secondary wound on each of the two "legs" of the transformer. This transformer is called?

Primary and secondary windings are split into two equal parts, with one half of the primary and one half of the secondary wound on each of the two "legs" of the transformer. This transformer is called?

a) current transformer
b) core type transformer
c) potential transformer
d) shell type transformer
e) resistance indicator




Answer: B

If the secondary voltage is smaller than primary voltage in a transformer. This transformer is called?

If the secondary voltage is smaller than primary voltage in a transformer. This transformer is called?

a) current transformer
b) step down transformer
c) potential transformer
d) step up transformer
e) resistance indicator







Answer: B

If the number of secondary turns is greater than the number of primary turns in a transformer. This transformer is called?

If the number of secondary turns is greater than the number of primary turns in a transformer. This transformer is called?

a) current transformer
b) step down transformer
c) potential transformer
d) step up transformer
e) resistance indicator

Answer: D

In a dc circuit, self-inductance is __ when voltage is at maximum, while in a ac circuit self inductance is __

In a dc circuit, self-inductance is __ when voltage is at maximum, while in a ac circuit self inductance is __

a. Not a factor, continually a factor
b. Sometimes a factor, not a factor
c. Continually a factor, not a factor
d. Not a factor, sometimes a factor






Answer: A

When relative movement ceases, production of induced E ceases. This process is called

When relative movement ceases, production of induced E ceases. This process is called 

a. Harmonic distortion
b. Self inductance
c. Mutual inductance
d. Electromagnetic induction




Answer: D

The size of the conductor is __ to the size of the current.

The size of the conductor is __ to the size of the current.

a. Inversely proportional
b. Proportional
c. Equal
d. None of the above

Answer: B

Transformer cooling oil has

Transformer cooling oil has

a) a very high specific heat
b) a poorer insulating characteristic than air
c) a very high fire point
d) no factors which necessitate better wire insulation
e) a very low safety hazard






Answer: A

Current transformers step down the current rather than the

Current transformers step down the current rather than the

a) resistance
b) flux strength
c) conductance
d) number of poles
e) voltage





Answer: E

The capacity of a transformer can be increased by: 1. submerging the core and windings in a tank of oil 2. submerging the core and windings in a tank of water 3. forced air cooling the oil in a heat exchanger 4. wrapping the core with a thermal insulation 5. forced air cooling of the core

The capacity of a transformer can be increased by:
1. submerging the core and windings in a tank of oil
2. submerging the core and windings in a tank of water
3. forced air cooling the oil in a heat exchanger
4. wrapping the core with a thermal insulation
5. forced air cooling of the core

a) 1, 3, 5
b) 2, 3, 4
c) 1, 4, 5
d) 2, 3, 4, 5
e) 2, 4, 5





Answer: A

Transformers are rated in terms of: 1. Volt amperes 2. Kilowatts 3. Kilovolt amperes 4. Ohms

Transformers are rated in terms of:
1. Volt amperes
2. Kilowatts
3. Kilovolt amperes
4. Ohms

a) 1, 2
b) 2, 4
c) 2, 3
d) 3, 4
e) 1, 3





Answer: E

A device used to change the voltage and current from one level to another, is known as a/an

A device used to change the voltage and current from one level to another, is known as a/an

a) conductor
b) resistor
c) alternator
d) transformer
e) power booster





Answer: D

Copper losses in a transformer are reduced by

Copper losses in a transformer are reduced by

a) using fan cooling
b) using oil cooling
c) using larger diameter wire
d) reducing the primary voltage
e) increasing the secondary voltage

Answer: C

A transformer works on the principle of

A transformer works on the principle of

a) reverse polarity
b) magnetic induction
c) DC power flowing in one direction
d) straight polarity
e) automatic induction





Answer: B

Transformers require:

Transformers require:

a. More maintenance than other electric machinery
b. Less maintenance than most other electric machinery
c. No maintenance
d. Inspection every three years
e. Inspection every month





Answer: B

The voltage induced in the secondary windings of the transformer, is _____ the turns ratio of the transformer.

The voltage induced in the secondary windings of the transformer, is _____ the turns ratio of the transformer.

a. Directly proportional to
b. Reversed to
c. Unrelated to
d. Opposed by
e. Inversely proportional to




Answer: A

A phenomenon produced by electric switchgear that can result in excessively high voltages in transformers is known as:

A phenomenon produced by electric switchgear that can result in excessively high voltages in transformers is known as:

a. Capacitive reactance
b. Inductive reactance
c. Phase lag
d. Reactive voltage losses
e. Harmonic distortion





Answer: E