Design of Electrical Machines Practice Test 4

1. The length of the mean turn of the winding is smallest with circular poles.

false

true

2. How are the bearing cooled in the construction?

air cooling

natural cooling

forced cooling

oil cooling

3. What type of winding is made use of small motors?

single layer lap winding

single layer wave winding

double layer wave winding

single layer mush winding

4. What type of winding is generally used for the stators?

single layer wave winding

single layer lap winding

double layer wave winding

double layer lap winding

5. What is the no load current percent of the full load current for the output of 0.75 KW?

40%

33%

90%

50%

6. What is the no load current percent of the full load current for the output of 37 KW?

67%

27%

30%

50%

7. What is the formula for mmf for air gap?

mmf for air gap = 800000 * air gap flux density / air gap factor * length of air gap

mmf for air gap = 800000 * air gap flux density * air gap factor / length of air gap

mmf for air gap = 800000 * air gap flux density * air gap factor * length of air gap

mmf for air gap = 800000 / air gap flux density * air gap factor * length of air gap

8. How are the stator windings of all synchronous generator connected?

star-delta connection

star connection

star connection with neutral earthed

delta connected

9. Which machine makes use of the forged steel construction?

high speed

very high speed

medium speed

low speed

10. The increase in number of poles, the dispersion coefficient increases and this gives a low power factor.

true

false