In a D.C. generator the critical resistance refers to the resistance of_____________?
A. brushes
B. field
C. armature
D. load
D.C. Generators
The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be_____________?
The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be_____________?
A. 640 V
B. 620 V
C. 600 V
D. 580 V
In the case of lap winding resultant pitch is____________?
In the case of lap winding resultant pitch is____________?
A. multiplication of front and back pitches
B. division of front pitch by back pitch
C. sum of front and back pitches
D. difference of front and back pitches
The function of pole shoes in the case of D.C. machine is______________?
The function of pole shoes in the case of D.C. machine is______________?
A. to reduce the reluctance of the mag¬netic path
B. to spread out the flux to achieve uniform flux density
C. to support the field coil
D. to discharge all the above functions
Flashing the field of D.C. generator means:______________?
Flashing the field of D.C. generator means:______________?
A. neutralising residual magnetism
B. creating residual magnetism by a D.C. source
C. making the magnetic losses of forces parallel
D. increasing flux density by adding extra turns of windings on poles
For a D.C. machines laboratory following type of D.C. supply will be suitable___________?
For a D.C. machines laboratory following type of D.C. supply will be suitable___________?
A. rotary converter
B. mercury are rectifier
C. induction motor D.C. generator set
D. synchronous motor D.C. generator set
In case of D.C. machine winding, number of commutator segments is equal to______________?
In case of D.C. machine winding, number of commutator segments is equal to______________?
A. number of armature coils
B. number of armature coil sides
C. number of armature conductors
D. number of armature turns
Welding generator will have____________?
Welding generator will have____________?
A. lap winding
B. wave winding
C. delta winding
D. duplex wave winding
Equilizer rings are required in case armature is_______________?
Equilizer rings are required in case armature is_______________?
A. wave wound
B. lap wound
C. delta wound
D. duplex wound
Eddy currents are induced in the pole shoes of a D.C. machine due to______________?
Eddy currents are induced in the pole shoes of a D.C. machine due to______________?
A. oscillating magnetic field
B. pulsating magnetic flux
C. relative rotation between field and armature
D. all above