Electrical Engineering · Question Bank

Alternators

109 of 157 questions match · page 6 of 6. Answer in your head first, then check the solution.

#101📘 EE Pocket Reviewer RojasEasy

An alternator is delivering power at a particular frequency. Which of the following can increase the operating frequency?

AIncrease the excitation

BDecrease the excitation

CIncrease the armature speed

DDecrease the armature speed

#102📘 EE Pocket Reviewer RojasEasy

Which statement is true about a salient pole type rotor in comparison to a cylindrical pole type rotor?

AIt is smaller in diameter and larger in axial length

BIt is larger in diameter and smaller in axial length

CIt is larger in diameter as well as axial length

DIt is smaller in diameter as well as axial length

#103📘 EE Pocket Reviewer RojasEasy

What is the disadvantage of using a short pitched coil in an alternator?

AThe voltage around the coil is reduced

BIt will produce harmonics

CIt increases the copper losses at the end connection

DIt causes unbalanced to the three-phase

#104📘 EE Pocket Reviewer RojasEasy

Which of the following is the effect of overheating of the alternator’s windings?

AIt reduces the voltage generated

BIt reduces the life of the machine

CIt reduces the operating power factor

DIt doesn't have any significant effect

#105📘 EE Pocket Reviewer RojasEasy

High speed alternators are driven by which of the following types of prime movers?

ASteam turbines

BHydraulic turbines

CDiesel engines

DAny of these

#106📘 EE Pocket Reviewer RojasEasy

The field windings of an alternator is excited with what current?

AAC only

BDC only

CEither AC or DC

DAny type of current

#107📘 EE Pocket Reviewer RojasEasy

If the input of the alternator is kept constant but its excitation is increased, then which of the following will happen?

AIts kVA will be leading

BIts kVA will be lagging

CIts kW will increase and its kVAR the same

DIts kW will decrease and its kVAR will increase

#108📘 EE Pocket Reviewer RojasEasy

What is the advantage of using salient poles in an alternator?

ALosses are reduced

BBearing loads are reduced

CIt is applicable to both low and medium speed prime movers

DFriction and windage loss will be reduced

#109📘 EE Pocket Reviewer RojasEasy

Two alternators are connected in parallel. Their kVAR and kW shares can be changed respectively by changing which of the following?

ASpeed and driving torque

BSpeed and excitation

CDriving torque and excitation

DExcitation and driving torque

More Electrical Engineering topics