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What is the relation of the copper loss and brush contacts with the total loss in small dc motors?
b Explanation: The copper loss and brush contact loss is being compared with the total loss in order to deduce an equation. The copper loss and brush contact loss is 2/3 times the total loss.
b
See lessExplanation: The copper loss and brush contact loss is being compared with the total
loss in order to deduce an equation. The copper loss and brush contact loss is 2/3 times
the total loss.
What type of excitation is used in the small universal commutator motors and what type of supply is provided?
b Explanation: The excitation which is provided is the series excitation in the small universal commutator motors. The type of supply provided is dc or ac supply
b
See lessExplanation: The excitation which is provided is the series excitation in the small
universal commutator motors. The type of supply provided is dc or ac supply
What is the angle at which the electromagnetic torque is maximum?
b Explanation: The electromagnetic torque is maximum at the angle of 45°. The range of operation of the reluctance motor lies in the range of 0-45
b
See lessExplanation: The electromagnetic torque is maximum at the angle of 45°. The range of
operation of the reluctance motor lies in the range of 0-45
What is the power factor in the reluctance motor and the range of efficiency?
d Explanation: The power factor in the reluctance motor is lagging power factor. The efficiency of the machine is about 55-75%
d
See lessExplanation: The power factor in the reluctance motor is lagging power factor. The
efficiency of the machine is about 55-75%
.What is the relation of the input voltage with the magnetic flux?
: c Explanation: The input voltage is given constant, which results in the constant magnetic flux. The magnetic flux is independent of the excitation
: c
See lessExplanation: The input voltage is given constant, which results in the constant magnetic
flux. The magnetic flux is independent of the excitation
Why is the three phase reluctance motor preferred over single phase reluctance motor?
a Explanation: The reluctance motor is a small synchronous motor with salient pole rotor. The single phase reluctance motors have the phenomenon of hunting.
a
See lessExplanation: The reluctance motor is a small synchronous motor with salient pole rotor.
The single phase reluctance motors have the phenomenon of hunting.
What is the relation between total iron loss for induction motors and the sum of stator tooth and core loss?
c Explanation: The total iron loss for induction motors is 1.5-2.5 times the sum of stator tooth and core loss. The total iron loss is due to fundamental frequency flux.
c
See lessExplanation: The total iron loss for induction motors is 1.5-2.5 times the sum of stator
tooth and core loss. The total iron loss is due to fundamental frequency flux.
.What is the formula of the end ring current?
Answer: d Explanation: The number of rotor slots and the bar current along with the number of poles is calculated. On substitution it gives the end ring current value
Answer: d
See lessExplanation: The number of rotor slots and the bar current along with the number of
poles is calculated. On substitution it gives the end ring current value
What is the range of the ratio of the total cross section of rotor bars to the total stator copper section for main winding for copper?
Answer: c Explanation: The minimum value of range of the ratio of the total cross section of rotor bars to the total stator copper section for main winding is 0.5. The maximum value range of the ratio of the total cross section of rotor bars to the total stator copper section for main winding is 0.8
Answer: c
See lessExplanation: The minimum value of range of the ratio of the total cross section of rotor
bars to the total stator copper section for main winding is 0.5. The maximum value range
of the ratio of the total cross section of rotor bars to the total stator copper section for
main winding is 0.8
What is the formula for the total cross section of rotor bars?
Answer: a Explanation: The number of rotor slots and area of each bar is first calculated. On substitution it gives the total cross section of rotor bars
Answer: a
Explanation: The number of rotor slots and area of each bar is first calculated. On
substitution it gives the total cross section of rotor bars
See less