Top 350+ Solved Electrical Machine 1 MCQ Questions Answer
Q. Where D.C. motor of H.P. 12 or more requires frequent starting, stopping,reversingand speed control
a. drum type controller is used
b. three point starter is used
c. four point starter is used
d. all above can be used
Q. If a D.C. shunt motor is working at full load and if shunt field circuit suddenlyopens
a. this will make armature to take heavy current, possibly burning it
b. this will result in excessive speed, possibly destroying armature due toexcessive centrifugal stresses
c. nothing will happen to motor
d. motor will come to stop
Q. D.C. motor is to drive a load which has certain minimum value for most of thetime and some peak value for short duration. We will select the
a. series motor
b. shunt motor
c. compound motor
d. any of the above
Q. D.C. motor is to a drive a load which is almost nil for certain part of the load cycleand peak value for short duration. We will select this
a. series motor
b. shunt motor
c. compound motor
d. any of the above
Q. Which D.C. motor has got maximum self relieving property ?
a. Series motor
b. Shunt motor
c. Cumulatively compounded motor
d. Differentially compounded motor
Q. In the D.C. motor the iron losses occur in
a. the field
b. the armature
c. the brushes
d. the commutator
Q. Laminations of core are generally made of
a. case iron
b. carbon
c. silicon steel
d. stainless steel
Q. Which of the following could be lamina-proximately the thickness of laminations of aD.C. machine ?
a. 0.005 mm
b. 0.05 mm
c. 0.5 m
d. 5 m
Q. The armature of D.C. generator is laminated to
a. reduce the bulk
b. provide the bulk
c. insulate the core
d. reduce eddy current loss
Q. 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
Q. The commutator segments are connected to the armature conductors by means of
a. copper lugs
b. resistance wires
c. insulation pads
d. brazing
Q. 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
Q. In D.C. generators the pole shoes are fastened to the pole core by
a. rivets
b. counter sunk screws
c. brazing
d. welding
Q. 63. Satisfactory commutation of D.C. machines requires
a. brushes should be of proper grade and size
b. brushes should smoothly run in the holders
c. smooth, concentric commutator properly undercut
d. all of the above