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
Electrical Machine Design
In D.C. machines the width of the duct is usually_____________?
In D.C. machines the width of the duct is usually_____________?
A. 4 mm
B. 6 mm
C. 8 mm
D. 10 mm
In D.C. machines, the ________ in field mmf results in increase in size and cost of machines?
In D.C. machines, the ________ in field mmf results in increase in size and cost of machines?
A. increase
B. decrease
C. either of the above
D. none of the above
Which of the following methods may be adopted to reduce the effects of armature reaction ?
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
In D.C. machines the number of slots per pole usually lies___________?
In D.C. machines the number of slots per pole usually lies___________?
A. between 2 to 4
B. between 6 to 8
C. between 9 to 16
D. between 20 to 30
In transformers using hot rolled steel, the cross-section of the yoke is made about __________ greater than that of the core?
In transformers using hot rolled steel, the cross-section of the yoke is made about __________ greater than that of the core?
A. 5 percent
B. 10 percent
C. 15 percent
D. 30 percent
E. none of the above
Power transformers have rating_______________?
Power transformers have rating_______________?
A. equal to 50 kVA
B. equal to 100 kVA
C. above 200 kVA
D. none of the above
____________are always double layer type?
____________are always double layer type?
A. Closed windings
B. Open windings
C. Either of the above
D. None of the above
The winding where dummy coils are used is sometimes called______________?
The winding where dummy coils are used is sometimes called______________?
A. duplex winding
B. triplex winding
C. forced winding
D. none of the above
When the two coil sides forming a coil are spaced exactly one pole pitch apart they are said to be of_____________?
When the two coil sides forming a coil are spaced exactly one pole pitch apart they are said to be of_____________?
A. short pitch
B. full pitch
C. either of the above
D. none of the above