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.Management Sciences
Category: D.C. Generators
The e.m.f. generated in a D.C. generator is directly proportional to____________?
A. flux/pole
B. speed of armature
C. number of poles
D. all of the above
In a level compounded D.C. generator, full load terminal voltage is______________?
A. negligibly low
B. equal to no-load terminal voltage
C. more than no-load terminal voltage
D. less than no-load terminal voltage
In a D.C. generator in case the resistance of the field winding is increased, then output voltage will____________?
A. increase
B. decrease
C. remain unaffected
D. fluctuate heavily
Permeance is the reciprocal of______________?
A. flux density
B. reluctance
C. ampere-turns
D. resistance
In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when____________?
A. r.p.m. is more than 300
B. r.p.m. is less than 300
C. number of poles is 4
D. number of poles is 2
In a D.C. generator:___________________?
A. external resistance = internal char-acteristic – armature reaction
B. internal characteristic = magnetisation characteristic – ohmic drop
C. external characteristic = magnetisation characteristic – ohmic drop – armature reaction
D. magnetisation characteristic = external characteristic
Fleming’s right-hand rule regarding direction of induced e.m.f., correlates__________?
A. magnetic flux, direction of current flow and resultant force
B. magnetic flux, direction of motion and the direction of e.m.f. induced
C. magnetic field strength, induced voltage and current
D. magnetic flux, direction of force and direction of motion of conductor
In D.C. generators, current to the external circuit from armature is given through_____________?
A. commutator
B. solid connection
C. slip rings
D. none of above
In D.C. generators, lap winding is used for______________?
A. high voltage, high current
B. low voltage, high current
C. high voltage, low current
D. low voltage, low current
The material for commutator brushes is generally_______________?
A. mica
B. copper
C. cast iron
D. carbon
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