0 : 0 : 1
1000 Design Electrical Machines
Which of the following is used to connect the armature conductors to the commutator?
b) Equalizer ring
What process takes place in an electric machine when stationary is kept in a time-varying field?
a) Energy conversion
b) Energy transference
c) Rotation of coil
d) Movement of coil
Which of the following is the same as the transformer emf?
a) Pulsational emf
b) Induction emf
c) Interactional emf
d) Motional emf
How will be the size and cost of a rotating electric machine that has a higher output coefficient be?
a) small size and more cost
b) small size and less cost
c) large size and more cost
d) large size and less cost
How will high specific loading according to rotating electric machine affect the efficiency?
a) Efficiency increases
b) Efficiency decreases
c) Efficiency may increase or decrease
d) Efficiency is not affected
What kind of layer winding in an electric machine occupies the whole slot by one coil side of the coil?
a) Single layer
b) Double layer
c) Single layer or Double layer
d) Mixture of single layer and double layer
What are the different types of interpoles in DC electric machines?
a) Parallel sided and Tapered
b) Open and closed
c) Single layer and double layer
d) Armature and field
What is the relation between hysteresis and the number of poles?
a) hysteresis loss decreases with an increase in number of poles
b) hysteresis loss increases with an increase in number of poles
c) hysteresis loss remains constant with an increase in number of poles
d) hysteresis loss may increase or decreases with an increase in number of poles
Which of these will increase with an increase in the number of poles?
a) Weight of field copper
c) Overall diameter of machine
d) Weight of armature copper
How should be the value of field mmf to prevent excessive distortion of field form by armature reaction in an electric machine?
a) large compared to armature mmf
b) small compared to armature mmf
d) large or small compared to armature mmf
Which of these windings are said to be bifurcated windings?
a) Whole coil winding
b) Semi-closed winding
c) half-coil winding
d) Hemitropic windings
How will the length of the air gap in a DC electric machine affect pulsational loss in pole faces?
a) Pulsational loss increases with an increase in air gap length
b) Pulsational loss decreases with an increase in air gap length
c) Pulsational loss does not change with an increase in air gap length
d) Pulsational loss may increase or decrease with an increase in air gap length
Which of these options are correct for a DC electric machine with a large air gap?
a) More pulsational loss in pole face
b) Quieter operation of the machine
c) Distorting effect of armature reaction more
d) No proper ventilation
How should be the number of slots in a DC electric machine for better cooling of armature conductors?
a) Large number of slots
b) Less number of slots
c) Slots equal to the number of poles
d) Number of slots depends on commutation
Which of the following circuit is made to insulate one conductor from another?
a) Electric circuit
b) Magnetic circuit
c) Dielectric circuit
d) Thermal circuit
How is the saturation level of ferromagnetic materials determined in electrical machines?
a) Using maximum allowable flux density
b) Using specific permeance
c) Using the linear velocity of material
d) Using maximum allowable loss
What part of electric machines will the temperature rise mainly affect?
a) Conductance of winding
b) Insulation of machine
c) Speed of machine
d) Torque of machine
How is the size of insulation determined?
a) By maximum voltage stress and maximum saturation
b) By mechanical stress
c) By maximum saturation and mechanical stress
d) By maximum voltage stress and mechanical stress
0 h : 0 m : 1 s
What's an issue?
Question is wrong
Answer is wrong
Want to elaborate a bit more? (optional)