Electrical Machine Mcqs Part 05

  1. In high nickel alloys the percentage of nickel is
    a. 5 to 10 percent
    b. 10 to 20 percent
    c. 30 to 50 percent
    d. 70 to 80 percent

42. Pumps, blowers and fans are usually called for
a. continuous duty
b. short time duty
c. intermittent periodic duty
d. intermittent periodic duty with starting and braking

43. Which of the following is normally called for continuous duty with starting and braking
a. Machine tools
b. Compressors
c. Sirens
d. Escalators

44. In lap windings, the equalizers rings are used to save
a. amature winding from carrying circulatings currents
b. commutator from carring circulating current
c. brushes from carrying circulating currents
d. amature core from eddy currents

45. Which of the following calls for intermittent duty with starting and braking
a. Pumps
b. Conveyors
c. Wind lasses
d. Cranes

46. The percentage of overload on a continue rating machine is
a. Zero
b. 5%
c. 10%
d. 50%

47. Open circuits test on a transformer is conducted to obtain
a. the leakage impedance
b. the ohmic loss
c. hysteresis loss only
d. core loss only
e. eddy current loss only

48. Heat transfer capability of hydrogen is nearly ….. times that of air
a. 2
b. 3
c. 7
d. 17

49. The density of hydrogen is that of air
a. 14
b. 1/4
c. 1/7
d. 1/14

50. Turbo-alternators of rating …….. and above are normally hydrogen cooled
a. 10 MW
b. 20 MW
c. 25 MW
d. 50 MW