Which of the following methods does not take into account the maximum temperature rise under variable load conditions ?

Related Mcqs:

1. By which of the following methods motor rating for variable load drives can be determined ?

   A. Method of average losses
   B. Equivalent current method
   C. Equivalent torque method
   D. Equivalent power method
   E. All of the above

2. By which of the following methods the temperature rise of windings and other parts may be determined ?

   A. Thermometer method
   B. Resistance method
   C. Embedded temperature detector method
   D. Any of the above

3. The time taken by the machine to attain 0.632 of its final steady temperature rise is called_____________?

   A. heating time constant
   B. cooling time constant
   C. either A. or B.
   D. none of the above

4. 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

5. If an insulating material is operated beyond the maximum allowable temperature, its life is_____________?

   A. drastically increased
   B. drastically reduced
   C. unaffected
   D. none of the above

6. Which of the following methods is used for air cooling of turbo-alternators ?

   A. One sided axial ventilation
   B. Two sided axial ventilation
   C. Multiple inlet system
   D. All of the above

7. Which of the following methods is most accurate ?

   A. Equivalent current method
   B. Equivalent power method
   C. Equivalent torque method
   D. Method of average losses

8. Which of the following methods may be adopted to reduce the effects of armature reaction ?

   A. Increase in length of air gap at pole tips
   B. Increasing reluctance of pole tips
   C. Compensating windings
   D. Interpoles
   E. All of the above

9. 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

10. The usual values of maximum flux densities for distribution transformers using hot rolled silicon steel are______________?

    A. 0.5 to 0.8 Wb/m2
    B. 0.8 to 1.0 Wb/m2
    C. 1.1 to 1.35 Wb/m2
    D. 1.4 to 1.8 Wb/m2