Related Questions

In _________ method of staging three phase induction motors the starting voltage is not reduced.
A Autotransformer
B Star-delta
C Slip ring
D Any of the above
Which one of the following is not necessarily the advantage of D.C. motors over A.C. motors?
A Low cost
B Wide speed range
C Stability
D High starting torque
If h₁ = inner film co-efficient and /h₂ = outer film co-efficient, then the overall heat transfer co-efficient is
A Always less than h₁
B Always between h₁ and h₂
C Always higher than h₂
D Dependent on metal resistance
Which of the following single-phase induction motors is generally used in time phonographs?
A Resistance start
B Capacitor start capacitor run
C Shaded pole
D Universal
In squirrel cage induction motors which of the following methods of starting cannot be used?
A Resistance in rotor circuit
B Resistance in stator circuit
C Autotransformer starting
D Star-delta starting
Which type of bearing is provided in small induction motors to support the rotor shaft?
A Ball bearings
B Cast iron bearings
C Bush bearings
D None of the above
In medium sized induction motors, the slip is generally around
A 0.04 %
B 0.4 %
C 4 %
D 14 %
Blocked rotor test on induction motors is used to find out
A Leakage reactance
B Power factor on short circuit
C Short-circuit current under rated voltage
D All of the above
In induction motors, the length of air gap in kept as small as mechanically possible is order to have
A low power factor
B high power factor
C high over load capacity
D any of the above
In three-phase squirrel-cage induction motors
A Rotor conductor ends are short-circuited through slip rings
B Rotor conductors are short-circuited through end rings
C Rotor conductors are kept open
D Rotor conductors are connected to insulation

Next steps