Alternators MCQs

Question 1

The regulation of an alternator is

Accepted Answer

the increase in terminal voltage when load is thrown off

Answer

the reduction in terminal voltage when alternator is loaded

Answer

the variation of terminal voltage under the condition of maximum and minimum excitation

Answer

the change in terminal voltage from lagging power factor to leading power factor

Question 2

An alternator is said to be over excited when it is operating at

Accepted Answer

leading power factor

Answer

lagging power factor

Answer

unity power factor

Answer

lagging to leading power factor

Question 3

An alternator driven by a Francis hydraulic turbine is a alternator

Accepted Answer

low or medium speed

Answer

low speed

Answer

medium speed

Answer

high speed

Question 4

If two alternators are running in proper synchronism and the voltage of one machine is suddenly increased

Accepted Answer

synchronising torque will be produced to restore further synchronism

Answer

both machines will stop

Answer

one machine will stop

Answer

none of the above

Question 5

Two alternators are to be put in parallel. Which of the follwing factors shold be identical for both?

Accepted Answer

All of the above

Answer

Frequency

Answer

Phase sequence

Answer

Voltage

Question 6

If the steam supply of an alternator running in parallel with another identical alternator is increased keeping its excitation constant, then

Accepted Answer

it will supply greater portion of the load

Answer

the power factor would be decreased

Answer

it would over-run the other alternator

Answer

its rotor will fall back in phase with respect to the other machine

Question 7

An exciter for a generator is a

Accepted Answer

shunt generator

Answer

shunt motor

Answer

series motor

Answer

series generator

Question 8

Two alternators '1' and '2' are sharing an inductive load equally. If the exctitation of alternator '1' is increased

Accepted Answer

alternator '2' will deliver less current and alternator '1' will deliver more current

Answer

alternator '2' will deliver motor current and alternator ' I' will deliver less current

Answer

both will deliver more current

Answer

both will continue to share load equally

Question 9

Which of the following coils is an alternator will have e.m.f. closer to sine waveform?

Accepted Answer

Distributed winding in short pitch coils

Answer

Distributed winding in full pitch coils

Answer

Concentrated winding in full pitch coils

Answer

Concentrated winding in short pitch coils