Top 150+ Solved Design of Electrical Machines MCQ Questions Answer
Q. The high voltage winding is usually which of the following type ?
a. Cylindrical winding with circular conductors
b. Cross-over winding with either circular or small rectangular conductors
c. Continuous disc type winding with rectangular conductors
d. All of the above types
Q. Which of the following is the basic consideration in the design of insulation ?
a. Electrical considerations
b. Mechanical considerations
c. Thermal considerations
d. All of the above
Q. A practical formula for determining the thickness of insulation between low voltageand high voltage windings is
a. 1 + 0.2 kVmm
b. 2 + 0.5 kVmm
c. 4 + 0.7 kV mm
d. 5 + 0.9 kV mm
Q. The insulation between windings and grounded core and the insulation between thewindings of the same phase is called
a. minor insulation
b. major insulation
c. either of the above
d. none of the above
Q. The cylindrical windings using circular conductors are used for current rating of
a. upto 20 A
b. upto 40 A
c. upto 60 A
d. upto 80 A
Q. The surge phenomenon is particularly important in case of
a. low voltage transformers
b. medium voltage transformers
c. high voltage transformers
d. any of the above
Q. Which of the following in an application of D.C. motors?
a. Traction
b. Drives for process industry
c. Battery driven vehicles
d. All of the above
Q. D.C. servomotors are used in
a. purely D.C. control systems
b. purely AC. control systems
c. both D.C. and AC. control systems
d. none of the above
Q. The stator of a D.C. machine comprises of
a. main poles
b. interpoles
c. frame
d. all of the above
Q. The laminations of the armature of a D.C. machine are usually _____ thick.
a. 0.1 to 0.2 mm
b. 0.2 to 0.3 mm
c. 0.3 to 0.4 mm
d. 0.4 to 0.5 mm
Q. ______ brushes are fragile and cause excessive wear of commutator,
a. Natural graphite
b. Hard carbon
c. Electro graphitic
d. Metal graphite
Q. Which of the following brushes can be used for high values of current density ?
a. Metal graphite brushes
b. Hard carbon brushes
c. Electro-graphitic brushes
d. Natural graphite brushes
Q. ________ is the common method of applying brushes to the commntator.
a. Radial
b. Trailing
c. Reaction
d. All of the above
Q. Which of the following problem arises in D.C. motors which are fed from thyristorbridge circuits ?
a. Increased I R losses
b. Increased core losses
c. Poor commutation
d. All of the above