4Th Class Power Engineering Chapter 82

Front 1

When magnetic flux produced by one coil induces an EMF in a second coil, it is called:

1) Capacitive reactance

2) Inductive reactance

3) Self inductance

4) Mutual inductance

5) Electromagnetic induction

Back 1

Mutual inductance

Front 2

Step-down transformers:

1) Have smaller diameter wire in the secondary windings

2) Have larger diameter wire in the secondary windings

3) Require smaller diameter wire in secondary coils

4) Have larger diameter wire in the primary windings

5) Have primary and secondary coils the same wire diameter

Back 2

Have larger diameter wire in the secondary windings

Front 3

Auto-transformers:

1) Use two windings for primary and secondary circuits

2) Can use less copper

3) Use more copper

4) Have large ratios of transformation

5) Have an equal ratio of transformation

Back 3

Can use less copper

Front 4

Transformer cooling oil has:

1) A poorer insulating characteristic than air

2) A very high fire point

3) A very low safety hazard

4) No factors that necessitate better wire insulation

5) A very high specific heat

Back 4

A very high specific heat

Front 5

Three major losses which occur in a transformer are iron losses, copper losses, and:

1) Inductive losses

2) Capacitive losses

3) Flux leakage

4) Heat losses

5) Cooling losses

Back 5

Flux leakage

Front 6

Transformers function on the principle of:

1) Interaction of residual magnetism

2) Mutual inductance

3) High resistance to DC current

4) Mutual conductance

5) Conductance

Back 6

Mutual inductance

Front 7

A transformer works on the principle of:

1) DC power flowing in one direction

2) Reverse polarity

3) Straight polarity

4) Automatic induction

5) Magnetic induction

Back 7

Magnetic induction

Front 8

Current transformers are:

1) Current step-up transformers

2) Voltage step-up transformers

3) High power factor transformers

4) Rectifying transformers

5) Power step-up transformers

Back 8

Voltage step-up transformers