323. For a D.C. machines laboratory following type of D.C. supply will be suitable
A. rotary converter
B. mercury are rectifier
C. induction motor D.C. generator set
D. synchronous motor D.C. generator set
324. The function of pole shoes in the case of D.C. machine is
A. to reduce the reluctance of the magnetic path
B. to spread out the flux to achieve uniform flux density
C. to support the field coil
D. to discharge all the above functions
325. 1n the cas of lap winding resultant pitch is
A. multiplication of front and back pitches
B. division of front pitch by back pitch
C. sum of front and back pitches
D. difference of front and back pitches
326. A D.C. welding generator has
A. lap winding
B. wave moving
C. duplex winding
D. any of the above
327. Which of the following statement about D.C. generators is false?
A. Compensating winding in a D.C. machine helps in commutation
B. In a D.C. generator interpoles winding is connected in series with the armature winding
C. Back pitch and front pitch are both odd and approximately equal to the pole pitch
D. Equilizing bus bars are used with parallel running of D.C. shunt generators
328. The demagnetising component of armature reaction in a D.C. generator
A. reduces generator e.m.f.
B. increases armature speed
C. reduced interpoles flux density
D. results in sparking trouble
329. The voltage drop for which of the following types of brush can be expected to be least?
A. Graphite brushes
B. Carbon brushes
C. Metal graphite brushes
D. None of the above
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