The bearings used to support the rotor shafts are generally
The bearings used to support the rotor shafts are generally
In a D.C. generator in order to reduce sparking at brushes, the self-induced e.m.f. in the coil is neutralized by all of the following except
In a D.C. generator in order to reduce sparking at brushes, the self-induced e.m.f. in the coil is neutralized by all of the following except
The essential condition for parallel operation of two D.C. generators is that they have
The essential condition for parallel operation of two D.C. generators is that they have
An exciter for a turbo generator is a
An exciter for a turbo generator is a
In D.C. generators the polarity of the interpoles
In D.C. generators the polarity of the interpoles
The number of armature parallel paths in a two-pole D.C. generator having duplex lap winding is
The number of armature parallel paths in a two-pole D.C. generator having duplex lap winding is
Laminations of core are generally made of
Laminations of core are generally made of
In a D.C. generator the critical resistance refers to the resistance of
In a D.C. generator the critical resistance refers to the resistance of
Number of tapings for each equalizer ring is equal to
Number of tapings for each equalizer ring is equal to
Inter-pole flux should be sufficient to
Inter-pole flux should be sufficient to
The rapid wear of brushes takes place due to
The rapid wear of brushes takes place due to
In case of D.C. machine winding, number of commutator segments is equal to
In case of D.C. machine winding, number of commutator segments is equal to
In a D.C. machine stray loss is the sum of
In a D.C. machine stray loss is the sum of
In D.C. generators on no-load, the air gap flux distribution in space is
In D.C. generators on no-load, the air gap flux distribution in space is
Which of the following could be lamina proximately the thickness of laminations of a D.C. machine?
Which of the following could be lamina proximately the thickness of laminations of a D.C. machine?
If a self excited D.C. generator after being installed, fails to build up on its first trial run, the first thing to do is to
If a self excited D.C. generator after being installed, fails to build up on its first trial run, the first thing to do is to
If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be
If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be
The open circuit voltage of a compound generator is 250 V. At full load the terminal voltage
The open circuit voltage of a compound generator is 250 V. At full load the terminal voltage
The voltage drop for which of the following types of brush can be expected to be least?
The voltage drop for which of the following types of brush can be expected to be least?
Magnetic field in a D.C. generator is produced by
Magnetic field in a D.C. generator is produced by
As a result of armature reaction, the reduction in the total mutual air gap flux in a D.C. generator is approximately
As a result of armature reaction, the reduction in the total mutual air gap flux in a D.C. generator is approximately
While applying Fleming's right-hand rule to and the direction of induced e.m.f., the thumb points towards
While applying Fleming's right-hand rule to and the direction of induced e.m.f., the thumb points towards
The insulating material used between the commutator segments is normally
The insulating material used between the commutator segments is normally
In a four-pole D.C. machine
In a four-pole D.C. machine
In D.C. generators, current to the external circuit from armature is given through
In D.C. generators, current to the external circuit from armature is given through
A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave
A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave
