Ward Leonard method of speed control is basically a______________?
(A) field control method
(B) armature controlled method
(C) field diverter
(D) frequency control method
Which of the following test can be performed on DC series motor?
(A) Swinburne test
(B) Hopkinson test
(C) Brake test
(D) Field test
Armature reaction in dc motor results___________?
(A) decrease in speed
(B) increase in speed
(C) short circuit
(D) open circuit
In a DC motor the inter-pole winding is connected in________________?
(A) series with field winding
(B) series speed armature winding
(C) parallel big field winding
(D) parallel with armature winding
A dc series motor should not be started on no load because it would___________?
(A) not develop starting torque
(B) fail to start without load
(C) run at dangerously high speed
(D) draw more current without producing sufficient torque
The resistance of armature winding depends on
(A) length of conductor
(B) cross-sectional area of the conductor
(C) number of conductors
(D) all of the above
The field coils of D.C. generator are usually made of_____________?
(A) mica
(B) copper
(C) cast iron
(D) carbon
In a commutator_____________?
(A) copper is harder than mica
(B) mica and copper are equally hard
(C) mica is harder than copper
(D) none of the above
According to Fleming’s right-hand rule for finding the direction of induced e.m.f., when middle finger points in the direction of induced e.m.f., forefinger will point in the direction of____________?
(A) motion of conductor
(B) lines of force
(C) either of the above
(D) none of the above
While applying Fleming’s right-hand rule to And the direction of induced e.m.f., the thumb points towards___________?
(A) direction of induced e.m.f.
(B) direction of flux
(C) direction of motion of the conductor if forefinger points in the direction of generated e.m.f.
(D) direction of motion of conductor, if forefinger points along the lines of flux