Category: D.C. Generators

A. demagnetisation of leading pole tip and magnetisation of trailing pole tip
B. demagnetisation of trailing pole tip and magnetisation of leading pole tip
C. damagnetising the center of all poles
D. magnetising the center of all poles

A. increasing its field resistance
B. decreasing its field resistance
C. increasing its speed
D. decreasing its speed

A. abrasion from dust
B. excessive spring pressure
C. rough commutator bars
D. high mica insulation between com-mutation bars
E. all of the above factors

A. flux/pole
B. speed of armature
C. number of poles
D. all of the above

A. negligibly low
B. equal to no-load terminal voltage
C. more than no-load terminal voltage
D. less than no-load terminal voltage

A. increase
B. decrease
C. remain unaffected
D. fluctuate heavily

A. flux density
B. reluctance
C. ampere-turns
D. resistance

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

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

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