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

Related Mcqs:

1. 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

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. __________is extensively used for those portions of magnetic circuit which carry steady flux and need superior mechanical properties ?

   A. Grey cast-iron
   B. Cast steel
   C. High carbon steel
   D. Stainless steel

4. The heat dissipated by from a surface depends upon its temperature and its characteristics like colour, roughness etc?

   A. conduction
   B. convection
   C. radiation
   D. any of the above

5. Machines cooled by direct cooling method may be called_____________?

   A. “supercharged”
   B. “inner cooled”
   C. “conductor cooled”
   D. any of the above

6. The distance between the starts of two consecutive coils measured in terms of coil sides is called_____________?

   A. front pitch
   B. winding pitch
   C. commutator pitch
   D. back pitch

7. In a D.C. machine the current per brush arm should not be more than_____________?

   A. 100 A
   B. 200 A
   E. 300 A
   D. 400 A

8. In a D.C. machine, the value of peripheral speed should not, normally, exceed___________?

   A. 10 m/s
   B. 20 m/s
   C. 30 m/s
   D. 40 m/s

9. In a D.C. machine the number of brush arms is _________ the number of poles?

   A. less than
   B. equal to
   C. greater than
   D. none of the above

10. The stator of a D.C. machine comprises of_____________?

    A. main poles
    B. interpoles
    C. frame
    D. all of the above