Q.1.
In a D.C. machine, the value of peripheral speed should not, normally, exceed
Q.2.
In a D.C. machine the current per brush arm should not be more than
Q.3.
In a D.C. machine the number of brush arms is _____ the number of poles.
Q.4.
The weight of copper of both armature and field windings decreases with _____ innumber of poles.
Q.5.
Which of the following problem arises in D.C. motors which are fed from thyristorbridge circuits ?
Q.6.
________ is the common method of applying brushes to the commntator.
Q.7.
Which of the following brushes can be used for high values of current density ?
Q.8.
______ brushes are fragile and cause excessive wear of commutator,
Q.9.
The laminations of the armature of a D.C. machine are usually _____ thick.
Q.10.
A practical formula for determining the thickness of insulation between low voltageand high voltage windings is
Q.11.
Dummy coil should not be used in
Q.12.
Power transformers have rating
Q.13.
Power transformers should be designed to have maximum efficiency
Q.14.
In transformers using hot rolled steel, the cross-section of the yoke is made about _____ greater than that of the core
Q.15.
Yokes with rectangular cross-section are used for
Q.16.
The cold rolled grain oriented steel has ______ permeability in the direction of thegrain orientation.
Q.17.
Cylindrical windings using circular conductors, employed in transformers, are
Q.18.
Helical windings are used in
Q.19.
Multi-layer helical windings are commonly used in the transformers as high voltagewindings
Q.20.
Disc windings are primarily used in
Q.21.
The heat dissipating capability of transformers of ratings higher thankVA inincreased by providing which of the following ?
Q.22.
Transformers with a capacity of upto _____ have a cooling radiator system with naturalcooling
Q.23.
The forced oil and air circulation method is usual one for transformers of capacities
Q.24.
The flash point of transformer oil should be higher than
Q.25.
D.C. windings are
Q.26.
The stator of a D.C. machine comprises of
Q.27.
D.C. servomotors are used in
Q.28.
Which of the following in an application of D.C. motors?
Q.29.
The surge phenomenon is particularly important in case of
Q.30.
The cylindrical windings using circular conductors are used for current rating of