a) loud speakers and tachometers
b) synchronous motors and moving iron instruments
c) dc shunt machines and solenoids
d) reluctance motors and synchronous motors
12) Electromagnetic torque in rotating electrical machinery is present when
a) air gap is uniform
b) stator winding alone carries current
c) rotor winding alone carries current
d) both stator and rotor windings carry current
13) A coil consists of
a) two conductors
b) two coil sides
c) two turns
d) four turns
14) A sinusoidal current sheet in a rotating electrical machine has peak value along q-axis.The peak value of sinusoidal mmf would be
a) in phase with current peak
b) 90 degree lagging the current peak
c) 90 degree leading the current peak
d) may lag or lead depending upon the type of machine
15) In all rotating electrical machines, electrical torque is developed when relative speed between stator field and rotor field is
a) zero
b) equal to rotor speed
c) equal and opposite to rotor speed
d) dependent upon the type of electrical machine
16) The torque speed characteristics of a repulsion motor resembles which of the following dc motor characteristics
a) Separately excited
b) Shunt
c) Series
d) Compound
17) Which type of motor is most suitable for computer printer drive
a) reluctance motor
b) hysteresis motor
c) Shaded pole motor
d) Stepper motor
18) The dc motor,which can provide zero speed regulation at full load with out any controller is
a) series
b) shunt
c) cumulative compound
d) differential compound
19) A 4 point starter is used to start and control the speed of a
a) dc shunt motor with armature resistance control
b) dc shunt motor with field weakening control
c) dc series motor
d) dc compound motor
20) An electric motor with constant out power will have a torque speed characteristic in the form of a
a) straight line through the origin
b) straight line parallel to the speed axis
c) circle about the origin
d) rectangular hyperbola
No comments:
Post a Comment