Objective type
What will happen if the exciter switch in the primemover is in the "ON" position during starting?
What happen to the Synchronous Motor if the exciter control knob is varied?
Which of the following is not a factor for the terminal voltage of a Separately Excited DC Shunt
Generator to decrease?
Which of the following is/are true for DC Shunt Generator:
(i) When the load increase, terminal voltage increases.
(ii) When the load increase, armature current increases.
(iii) When the load increase, power generated increases.
When is the degree of compounding of a DC Compound Generator is said to be flat compounded
What type of compounding is ideal to be utilized when the output of the generator needs to be
transmitted over long distances via cables or bus bar?
What do you call the compounding when the flux created by the series field opposes that of the shunt
field?
True or False
In a dc motor, it is not possible to have an odd number of poles.
n a dc motor, it is possible to have an odd number of parallel paths
In a dc motor, it is not possible to have an odd number of conductors
In dc motors, there are no classifications like self-excited or separately excited motors.
To change the rotation of a dc motor, either change the connection of the field or of the armature but
not both.
The smaller is the load of the motor, the smaller is its counter emf.
In a shunt motor, if the field circuit resistance is not changed, the flux of the motor may be considered
as constant.
In a motor, as the flux increases, the torque decreases.
In a motor, as the flux increases, the speed decreases.
In a dc motor, the speed at full-load is always less than the speed at no-load
In a dc generator, the counter emf at standstill is equal to the terminal voltage.
If a dc motor has no-load, its armature current is zero.
For constant speed application, the higher is the speed regulation, the better.
If in dc generators there are self-excited and separately excited, in dc motors there are also self-excited
and separately excited
If a dc motor has no-load, its armature current is zero
For constant speed application, the higher is the speed regulation, the better
The smaller is the armature current in a motor, the smaller is the torque
The starting current of a motor is higher than its running current.
In a motor, the starting torque is less than the running torque
As the flux increases in a motor, the speed also increases
In a motor, the counter emf may be greater than the terminal voltage
In a motor, the counter emf is always less than the terminal voltage.
In a motor, the higher is the starter resistance, the higher is the starting current.
As the load of a motor increases, its speed decreases
1 N-m of torque is greater than 1 ft-lb of torque.
1 rps of speed is the same as 60 rpm of speed.
Short Answer
A 150-V shunt motor has an armature and shunt field resistances of 0.20 and 150 Ohms respectively.
This motor draws 32 A of current from its source. Its rotational losses amount to 400 W. If the brush
contact drop is 3 V total, find the armature current
A 150-V shunt motor has an armature and shunt field resistances of 0.20 and 150 Ohms respectively.
This motor draws 32 A of current from its source. Its rotational losses amount to 400 W. If the brush
contact drop is 3 V total, find the motor's counter emf.
A 150-V shunt motor has an armature and shunt field resistances of 0.20 and 150 Ohms respectively.
This motor draws 32 A of current from its source. Its rotational losses amount to 400 W. If the brush
contact drop is 3 V total, find horsepower developed.
What is the rated torque in N-m of a motor if it has a rating of 12 Hp, and a speed of 1,200 rpm?
A 6-pole, 50 conductor, lap winding, 115-V shunt motor has an armature and shunt field resistances of
0.12 and 115 Ohms respectively. This motor draws 20 A of current from its source and establishes a field
of 200 mWb per pole. The brush contact drop is 2 V total. Its rotational losses is 200 watts. Find the
motor's speed in rpm.