WorksheetsDC Motors and Transformers Quiz
Total questions: 10
Worksheet time: 5mins
Back emf is the phenomena occurred in _________
DC generator
DC motor
AC motor
DC Machines
The main advantage of dc motors compared to ac motors is
Less maintenance
Low starting torque
Low cost
Speed control
In DC Motor speeds above the rated speed can be attained by varying which of the following winding current
Field winding
Armature winding
Either field or armature winding
Not possible
Starter is used in DC Motor for which of the following purpose:
Improve efficiency
Reduce starting current
Improving starting torque
Improving Back EMF
For machine tools, which DC motor can be used?
DC Series motor
DC Shunt motor
DC cumulative compound motor
DC differential compound motor
In a DC shunt motor, speed is related to armature current as _____________
Directly proportional to the armature current
Proportional to the square of the current
Independent of armature current
Inversely proportional to the armature current
If the supply frequency of a transformer increases, the secondary output voltage of the transformer
Increase
Decrease
Remain the same
Increase as a square of it
Transformer ratings are given in _____________
HP
KW
KVA
KVAR
The purpose of the transformer core is to provide ____________
Low reluctance path
High inductive path
High capacitive path
High reluctance path
Which type of flux does transformer action need?
Alternating electric flux
Constant magnetic flux
Increasing magnetic flux
Alternating magnetic flux
