A. Increased I R losses
B. Increased core losses
C. Poor commutation
D. Change in motor parameters
E. All of the above
Related Mcqs:
- Which of the following materials is used in the manufacture of resistance grids to be used in the starters of large motors ?
A. Copper
B. Aluminium
C. Steel
D. Cast-iron - Which of the following in an application of D.C. motors?
A. Traction
B. Drives for process industry
C. Battery driven vehicles
D. Automatic control
E. 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 self cooled motors the cooling time constant is about ___________ than the heating time constant because cooling conditions are worse at standstill?
A. 2 to 3 times greater
B. 3 to 4 times greater
C. 4 to 5 times greater
D. none of the above - Which of the following methods does not take into account the maximum temperature rise under variable load conditions ?
A. Equivalent power method
B. Equivalent current method
C. Method of average losses
D. Equivalent torque method - The design of electromagnets is based upon which of the following fundamental equations ?
A. Force equation
B. Magnetic circuit equation
C. Heating equation
D. Voltage equation
E. All of the above - Which of the following brushes can be used for high values of current density ?
A. Metal graphite brushes
B. Hard carbon brushes
C. Electro-graphitic brushes
D. Natural graphite brushes - The high voltage winding is usually which of the following type ?
A. Cylindrical winding with circular conductors
B. Cross-over winding with either circular or small rectangular conductors
C. Continuous disc type winding with rectangular conductors
D. All of the above types - The voltage control in electric supply networks in required on account of which of the following reasons ?
A. Adjustment of voltage at consumers premises within statutory limits
B. Control of active and reactive power
C. Adjustment of short period daily and seasonal voltage variations in accordance with variations of load
D. All of the above - Which of the following is the major consideration to evolve a good design?
A. Cost
B. Durability
C. Compliance with performance criteria as laid down in specifications
D. All of the aboveSubmitted by: Abid