Element of Electrical Design (3160918) MCQs

MCQs of GENERAL DESIGN ASPECTS

Showing 21 to 30 out of 84 Questions
21.

Out of the following materials, the area of hysteresis loop will be least for………

(a)

soft steel

(b)

silicon steel

(c)

hard steel

(d)

wrought iron

Answer:

Option (b)

22.

Which factor is used to justify the following statement? 

"The length of the core is not occupied by iron only; some part of the length is occupied by ventilating ducts as well as insulation between the steel lamination. 

(a)

Stacking Factor

(b)

Leakage Flux co-eficient 

(c)

Field Form Factor

(d)

Winding Factor

Answer:

Option (a)

23.

____________________ = Net iron length LiGross iron length Lg

(a)

Field Form Factor 

(b)

Carter’s gap coefficient

(c)

Carters fringe curves

(d)

Stacking Factor 

Answer:

Option (d)

24.

What is the function of the leakage flux?

(a)

contributes to the transfer of energy

(b)

contributes to the conversion of energy

(c)

contributes to both the conversion of energy and transfer of energy

(d)

does not contributes to the conversion or transfer of energy

Answer:

Option (d)

25.

What is the formula to obtain the hysteresis loss devised by Steinmetz?

(a)

hysteresis loss = hysteresis coefficient / frequency of magnetization * (maximum flux density)steinmetz coefficient

(b)

hysteresis loss = hysteresis coefficient * frequency of magnetization / (maximum flux density)steinmetz coefficient

(c)

hysteresis loss = hysteresis coefficient * frequency of magnetization * (maximum flux density)Steinmetz coefficient

(d)

hysteresis loss = 1/hysteresis coefficient * frequency of magnetization * (maximum flux density)Steinmetz coefficient

Answer:

Option (c)

26.

How are the eddy current losses in the machine reduced?

(a)

by using conducting materials

(b)

by using magnetic materials

(c)

by using insulating materials

(d)

by laminating the core

Answer:

Option (d)

27.

What are the factors the slot leakage permeance will depend upon?

(a)

shape of the slot

(b)

arrangement of winding in the slot

(c)

number of windings

(d)

shape of the slot and arrangement of winding in the slot

Answer:

Option (d)

28.

What is the formula of the permeance of the strip in the conductor portion?

(a)

permeance of the strip = permeability in air * area of the flux path * length of flux path

(b)

permeance of the strip = permeability in air / area of the flux path * length of flux path

(c)

permeance of the strip = permeability in air * area of the flux path / length of flux path

(d)

permeance of the strip =1 / permeability in air * area of the flux path * length of flux path

Answer:

Option (c)

29.

 What is the formula of the effective permeance of conductor portion?

(a)

effective permeance of conductor portion = 1/total flux linkages * total turns * total mmf

(b)

effective permeance of conductor portion = total flux linkages / total turns * total mmf

(c)

effective permeance of conductor portion = total flux linkages * total turns * total mmf

(d)

effective permeance of conductor portion = total flux linkages * total turns / total mmf

Answer:

Option (b)

30.

What is pulsation losses?

(a)

flux pulsations are caused due to the slotted armature

(b)

flux pulsations are caused due to the rotation of machine

(c)

flux pulsation occurs due to rotor slots are rotating

(d)

flux pulsations occur due to the change in reluctance

Answer:

Option (d)

Showing 21 to 30 out of 84 Questions