Q.1
Equalizer rings are required in case armature is
Q.2
According to Fleming's right-hand rule for finding the direction of induced e.m.f., when middle finger points in the direction of induced e.m.f., forefinger will point in the direction of
Q.3
If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be
Q.4
In D.C. generators, current to the external circuit from armature is given through
Q.5
In a four-pole D.C. machine
Q.6
The demagnetizing component of armature reaction in a D.C. generator
Q.7
In D.C. generators, lap winding is used for
Q.8
Copper brushes in D.C. machine are used
Q.9
Which of the following generators will be preferred if they are required to be run in parallel?
Q.10
In over compounded generator, full load terminal voltage is
Q.11
The rapid wear of brushes takes place due to
Q.12
In case of D.C. machine winding, number of commutator segments is equal to
Q.13
Following energized winding of a D.C. machine should not be opened as it would produce high inductive voltage which may be dangerous to personnel and may cause its own insulation failure.
Q.14
The essential condition for parallel operation of two D.C. generators is that they have
Q.15
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
Q.16
The open circuit voltage of a compound generator is 250 V. At full load the terminal voltage
Q.17
While applying Fleming's right-hand rule to and the direction of induced e.m.f., the thumb points towards
Q.18
The voltage drop for which of the following types of brush can be expected to be least?
Q.19
In a D.C. machine stray loss is the sum of
Q.20
As a result of armature reaction, the reduction in the total mutual air gap flux in a D.C. generator is approximately
Q.21
An exciter for a turbo generator is a
Q.22
Laminations of core are generally made of
Q.23
In D.C. generators on no-load, the air gap flux distribution in space is
Q.24
The purpose of providing dummy coils in a generator is
Q.25
Brushes of D.C. machines are made of
Q.26
The insulating material used between the commutator segments is normally
Q.27
The bearings used to support the rotor shafts are generally
Q.28
When two D.C. series generators are running in parallel, an equalizer bar is used
Q.29
When two D.C. generators are running in parallel an equalizer bar is used
Q.30
D.C. generator generally preferred for charging automobile batteries is
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