Electrical machine design

41. The action of electromagnetic machines can be related to which of the following basic principles ?

Induction
Interaction
Alignment
All of the above

Detailed SolutionThe action of electromagnetic machines can be related to which of the following basic principles ?

42. Damping of the Ballistic galvanometer is made small to

get first deflection large
make the system oscillatory
make the system critically damped
get minimum overshoot

Detailed SolutionDamping of the Ballistic galvanometer is made small to

43. The design of electromagnets is based upon which of the following fundamental equations ?

Force equation
Magnetic circuit equation
Heating equation
Voltage equation E. All of the above

Detailed SolutionThe design of electromagnets is based upon which of the following fundamental equations ?

44. The adjustment of position of shading bands, in an energy meter is done to provide

friction compensation
creep compensation
braking torque
none of the above

Detailed SolutionThe adjustment of position of shading bands, in an energy meter is done to provide

45. In order to achieve high accuracy, the slide wire of a potentiometer should be

as long as possible
as short as possible
neither too small not too large
very thick

Detailed SolutionIn order to achieve high accuracy, the slide wire of a potentiometer should be

46. ________ has a lowrelative permeability and is used principally in field frames when cost is of primary importance and extra weight is not objectionable.

Cast steel
Aluminium
Soft steel
Cast iron

Detailed Solution________ has a lowrelative permeability and is used principally in field frames when cost is of primary importance and extra weight is not objectionable.

47. Two holes in the disc of energy meter are drilled at the opposite sides of the spindle to

improve its ventilation
eliminate creeping at no load
increase its deflecting torque
increase its braking torque

Detailed SolutionTwo holes in the disc of energy meter are drilled at the opposite sides of the spindle to

48. Various adjustments in an energy meter include

light load or friction
lag and creep
overload and voltage compensation
temperature compensation E. all of the above

Detailed SolutionVarious adjustments in an energy meter include

49. In an energy meter braking torque is produced to

safe guard it against creep
brake the instrument
bring energy meter to stand still
maintain steady speed and equal to driving torque

Detailed SolutionIn an energy meter braking torque is produced to

50. The thermal conductivity of hydrogen is ______ times that of air

2
3
5
7

Detailed SolutionThe thermal conductivity of hydrogen is ______ times that of air

Page 1Page 2Page 3Page 4Page 5
Test 1Test 2Test 3Test 4