PHYSICS: D.C. MACHINE 08/08 Online Test

Which of the following equipments require high starting torque?
Crane
Reciprocating pumps
Electric locomotives
All of the above
The efficiency of D.C motor for maximum power transfer will be
50%
80%
90%
100%.
Which of the following generator do not have terminal voltage while running on no-load under healthy condition
Shunt generator
Series generator
Separately excited generator
Compound generator
To achieve spark less commutation, brushes of a D.C generator are sifted ahead so as to bring
Axis
In magnetic neutral axis
Just ahead of magnetic neutral axis
Just behind the magnetic neutral
For which of the following applications D.C motors are considered as most suitable?
Water pumps
Fans
Floor mills
Traction
In a D.C series motor, speed
Increase as flux decreases
Is controlled by shunt field
Increases as armature circuit resistance increases
Cannot be controlled by using diverter resistance
/
I only
II and III
I and III
III only
In which of the following braking, the terminal polarities are reversed during braking?
Plugging
Regenerative
Rheostatic
Dynamic
Number of toppings for each equalizer ring is equal to
Number of poles
Number of parallel paths
Number of pole pair
Number of commutator segments
In D.C generators, at no-load, the air gap flux distribution in space is
Pulsating
Sinusoidal
Flat topped
In a D.C motor back emf depends upon
Speed of the machine
Strength of the magnetic field
Number of armature conductors
All of these
Stray loss in a D.C machine is the sum of
Iron loss and mechanical loss
Copper loss and mechanical loss
Field copper loss and mechanical loss
Armature copper loss and iron loss
Which of the following may constitute short-circuit in the armature winding?
Insulator failure between two commutator segments
Inter turn insulation failure
(1) and or (2)
Loss of residual magnetism
Which of the following equipments require high starting torque?
Crane
Reciprocating pumps
Electric locomotives
All of the above
The efficiency of d.c. motor for maximum power transfer will be
50%
80%
90%
100%.
Which of the following generator do not have terminal voltage while running on no-load under healthy condition
Shunt generator
Series generator
Separately excited generator
Compound generator
For which of the following applications d.c. motors are considered as most suitable?
Water pumps
Fans
Floor mills
Traction
In a d.c. series motor, speed
Increase as flux decreases
Is controlled by shunt field
Increases as armature circuit resistance increases
Cannot be controlled by using diverter resistance
/
I only
II and III
I and III
III only
In which of the following braking, the terminal polarities are reversed during braking?
Plugging
Regenerative
Rheostatic
Dynamic
Description:

This is test is a part of a series of eight test which helps students to check the level of knowledge in Electricity, specifically in the DC Machine in Physics.

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