Electrical Machine Design MCQ

Welcome to your Electrical Machine Design MCQ

Which of the following kind of conductors will require thicker insulation?

Large sized conductor

Small-sized conductor

Conductors with high permeance

Conductors with low permeance

None

Which of the following materials is generally used in the design of electromagnetic machines?

Paramagnetic materials

Diamagnetic materials

Ferromagnetic materials

Core-magnetic materials

None

Which of the following circuit is designed to dissipate heat produced in the machine?

Electric circuit

Magnetic circuit

Dielectric circuit

Thermal circuit

None

What must be mainly ensured to keep the temperature rise within limits?

Good efficiency of the machine

Proper cooling and ventilation

Proper saturation level

Good insulation

None

How is the size of insulation determined?

By maximum voltage stress and maximum saturation

By mechanical stress

By maximum saturation and mechanical stress

By maximum voltage stress and mechanical stress

None

What part of electric machines will the temperature rise mainly affect?

Conductance of winding

Insulation of machine

Speed of machine

Torque of machine

None

How is the saturation level of ferromagnetic materials determined in electrical machines?

Using maximum allowable flux density

Using specific permeance

Using the linear velocity of material

Using maximum allowable loss

None

Which of the following circuit is made to insulate one conductor from another?

Electric circuit

Magnetic circuit

Dielectric circuit

Thermal circuit

None

How should be the number of slots in a DC electric machine for better cooling of armature conductors?

Large number of slots

Less number of slots

Slots equal to the number of poles

Number of slots depends on commutation

None

10.

How should be the value of field mmf to prevent excessive distortion of field form by armature reaction in an electric machine?

large compared to armature mmf

small compared to armature mmf

large or small compared to armature mmf

None

11.

Which of these windings are said to be bifurcated windings?

Whole coil winding

Semi-closed winding

half-coil winding

Hemitropic windings

None

12.

Which of these options are correct for a DC electric machine with a large air gap?

More pulsational loss in pole face

Quieter operation of the machine

Distorting effect of armature reaction more

No proper ventilation

None

13.

How will the length of the air gap in a DC electric machine affect pulsational loss in pole faces?

Pulsational loss increases with an increase in air gap length

Pulsational loss decreases with an increase in air gap length

Pulsational loss does not change with an increase in air gap length

Pulsational loss may increase or decrease with an increase in air gap length

None

14.

Which of the following factor mainly determines the type of insulation for an electrical machine?

Maximum allowable flux density

Maximum operating temperature

Maximum efficiency of the machine

Maximum allowable loss in machine

None

15.

What kind of materials are used to design electrical heating devices?

High Conductivity Materials

High Resistivity Materials

High Weldability Materials

High Solderability Materials

None

16.

What determines the output of a dc electric machine?

Only Total Magnetic loading

Only Total Electric loading

Total loadings

Either Total Magnetic loading or Total Electric loading

None

17.

What are the main dimensions of a rotating electric machine?

Field diameter and Armature core length

Armature diameter and Armature core length

Armature diameter and Field core length

Field diameter and Field core length

None

18.

What kind of emf is produced in an electric machine when the coil is stationary and flux varies with time?

Transformer emf

Motional emf

Interactional emf

Induction emf

None

19.

How should be the magnetic and electrical loadings in a highly efficient electric machine?

It must be small

It must be large

It must be equal to the current density

It must be equal to the flux density

None

20.

How will the size and cost of a rotating electric machine be if it is designed with greater speed?

small size and more cost

small size and less cost

large size and more cost

large size and less cost

None

21.

How should be the specific loadings to design a machine with reduced dimensions?

Increased values of specific loadings

Decreased values of specific loadings

Zero specific loadings

Moderate values of specific loadings

None

22.

How should be the output coefficient of a rotating electric machine from an economics point of view?

High

Low

Moderate

Output coefficient does not affect the economics

None

23.

What is the relation between the output coefficient to the volume of active parts in a rotating electric machine?

directly proportional

inversely proportional

equal to

No relation can be established

None

24.

Where does maximum flux density occur in a well-designed electric machine?

In the rotor

In the air gap

In the teeth

In the poles

None

25.

What is the other name for a short-pitched coil electrical machine?

Coiled

Commutated

Winded

Chorded

None

1 out of 25

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