Top 350+ Solved Electrical Machine 1 MCQ Questions Answer
Q. Auto-transformer makes effective saving on copper and copper losses, whenitstransformation ratio is
a. approximately equal to one
b. less than one
c. great than one
d. none of the above
Q. Minimum voltage regulation occurs when the power factor of the load is
a. unity
b. lagging
c. leading
d. zero
Q. In a step-down transformer, there is a change of 15 A in the load current. This results inchange of supply current of
a. less than 15 A
b. more than 15 A
c. 15 A
d. none of the above
Q. No-load speed of which of the following motor will be highest ?
a. Shunt motor
b. Series motor
c. Cumulative compound motor
d. Differentiate compound motor
Q. The direction of rotation of a D.C. series motor can be changed by
a. interchanging supply terminals
b. interchanging field terminals
c. either of (a) and (b) above
d. None of the above
Q. Which of the following application requires high starting torque ?
a. Lathe machine
b. Centrifugal pump
c. Locomotive
d. Air blower
Q. If a D.C. motor is to be selected for conveyors, which rriotor would be preferred ?
a. Series motor
b. Shunt motor
c. Differentially compound motor
d. Cumulative compound motor
Q. Which D.C. motor will be preferred for machine tools ?
a. Series motor
b. Shunt motor
c. Cumulative compound motor
d. Differential compound motor
Q. Differentially compound D.C. motors can find applicationsrequiring
a. high starting torque
b. low starting torque
c. variable speed
d. frequent on-off cycles
Q. Which D.C. motor is preferred for elevators ?
a. Shunt motor
b. Series motor
c. Differential compound motor
d. Cumulative compound motor
Q. If the field of a D.C. shunt motor gets opened while motor is running
a. the speed of motor will be reduced %
b. the armature current will reduce
c. the motor will attain dangerously high speed 1
d. the motor will continue to nuvat constantspeed
Q. Starters are used with D.C. motors because
a. these motors have high starting torque
b. these motors are not self-starting
c. back e.m.f. of these motors is zero initially
d. to restrict armature current as there is no back e.m.f. whilestarting
Q. In D.C. shunt motors as load is reduced
a. the speed will increase abruptly
b. the speed will increase in proportion to reduction in load
c. the speed will remain almost/constant
d. the speed will reduce
Q. A D.C. series motor is that which
a. has its field winding consisting of thick wire and lessturns
b. has a poor torque
c. can be started easily without load
d. has almost constant speed
Q. For starting a D.C. motor a starter is required because
a. it limits the speed of the motor
b. it limits the starting current to a safe value
c. it starts the motor
d. none of the above