Related Questions

A wound rotor induction motor is preferred, as compared to squirrel cage induction motor, when major consideration is
A Slop speed operation
B High starting torque
C Low windage losses
D All of the above
A thin mild steel wire is loaded by adding loads in equal increments till it breaks. The extensions noted with increasing loads will behave as under
A Uniform throughout
B Increase uniformly
C First increase and then decrease
D Increase uniformly first and then increase rapidly
While starting a synchronous motor by induction motor action, field winding is usually
A connected to D.C. supply
B short-circuited by low resistance
C kept open-circuited
D none of the above
A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is mainly because
A synchronous motor has no slip
B stator supply is not required to produce magnetic field
C mechanical load on the rotor remains constant
D synchronous motor has large airgap
While starting a salient pole synchronous motor by induction motor action and connecting field discharge resistance across field, starting and accelerting torque is produced by
A induction motor torque in field winding
B induction motor torque in damper winding
C eddy current and hysteresis torque in pole faces
D reHetance motor torque due to saliency of the rotor
E all of the above methods
Slip ring motor is preferred over squirrel cage induction motor where
A High starting torque is required
B Load torque is heavy
C Heavy pull out torque is required
D All of the above
The power factor of a synchronous motor is better than that of induction motor because
A stator supply is relieved of responsibility of producing magnetic field
B mechanical load on the motor can be adjusted
C synchronous motor runs at synchronous speed
D synchronous motor has large air gap
An important advantage of a synchronous motor over wound round induction motor is that
A its power factor may be varied at will
B its speed is independent of supply frequency
C its speed may be controlled more easily
D none of the above
Mass moment of inertia of a thin rod about its one end is ___________ the mass moment of inertia of the same rod about its mid-point
A Same as
B Twice
C Thrice
D Four times
The ratio of the moment of inertia of a rectangle about its centroidal axis to the moment of inertia about its base, is
A $$\frac{1}{4}$$
B $$\frac{1}{2}$$
C $$\frac{3}{4}$$
D $$2$$

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