Computer Programming MCQs

5739 MCQs  (Page 519 of 574)

While selecting motor for an air conditioner which of the following characteristics is of great importance ?
A. type of bearings
B. type of enclosure
C. nosie
D. arrangement for power transmis¬sion
Which of the following types of motor enclosure is safest ?
A. totally enclosed
B. totally enclosed fan cooled
C. open type
D. semi closed
For a D.C. shunt motor which of the following is incorrect ?
A. unsuitable for heavy duty starting
B. torque varies as armature current
C. torque-armature current is a straight line
D. torque is zero for zero armature current
Which of the following motors has series characteristics ?
A. shaded pole motor
B. repulsion motor
C. capacitor start motor
D. none of the above
In series motor which of the following methods can be used for changing the flux per pole ?
A. tapped field control
B. diverter field control
C. series-parallel control
D. any of the above
The diameter of the rotor shaft for an electric motor depends on which of the following ?
A. r.p.m. only
B. horse power only
C. horse power and r.p.m.
D. horse power, r.p.m. and power factor
Which of the following motors is preferred when smooth and precise speed control over a wide range is desired ?
A. d.c. motor
B. squirrel cage induction motor
C. wound rotor induction motor
D. synchronous motor
Which of the following happens when star-delta starter is used ?
A. starting voltage is reduced
B. starting current is reduced
C. both a. and b.
D. none of the above