For the parallel operation of two or more D.C. compound generators, we should ensure that
For the parallel operation of two or more D.C. compound generators, we should ensure that
The e.m.f. generated by a shunt wound D.C. generator is E. Now while pole flux remains constant, if the speed of the generator is doubled, the e.m.f. generated will be
The e.m.f. generated by a shunt wound D.C. generator is E. Now while pole flux remains constant, if the speed of the generator is doubled, the e.m.f. generated will be
In a shunt generator the voltage build up is generally restricted by
In a shunt generator the voltage build up is generally restricted by
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
In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis, when
In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis, when
A D.C. generator can be considered as
A D.C. generator can be considered as
In a D.C. generator
In a D.C. generator
In case of a flat compounded generator
In case of a flat compounded generator
Satisfactory commutation of D.C. machines requires
Satisfactory commutation of D.C. machines requires
Shunt generators are most suited for stable parallel operation because of their
Shunt generators are most suited for stable parallel operation because of their
The purpose of providing dummy coils in a generator is
The purpose of providing dummy coils in a generator is
The main factor which leads to unstable parallel operation of flat and over compounded generators is
The main factor which leads to unstable parallel operation of flat and over compounded generators is
In a separately excited generator supplying rated load the armature reaction:
In a separately excited generator supplying rated load the armature reaction:
A cumulatively compounded long shunt generator when operating as a motor would be
A cumulatively compounded long shunt generator when operating as a motor would be
The e.m.f. generated in a D.C. generator is directly proportional to
The e.m.f. generated in a D.C. generator is directly proportional to
Which of the following generator will have negligible terminal voltage while running on no-load?
Which of the following generator will have negligible terminal voltage while running on no-load?
Open circuited armature coil of a D.C. machine is
Open circuited armature coil of a D.C. machine is
In D.C. generators, the cause of rapid brush wear may be
In D.C. generators, the cause of rapid brush wear may be
Which of the following generators will be preferred if they are required to be run in parallel?
Which of the following generators will be preferred if they are required to be run in parallel?
In case of D.C. machines, mechanical losses are primary function of
In case of D.C. machines, mechanical losses are primary function of
A series generator can self-excite
A series generator can self-excite
For a D.C. generator when the number of poles and the number of armature conductors is fixed, then which winding will give the higher e.m.f.?
For a D.C. generator when the number of poles and the number of armature conductors is fixed, then which winding will give the higher e.m.f.?
Compensating windings are used in D.C. generators
Compensating windings are used in D.C. generators
Fleming's right-hand rule regarding direction of induced e.m.f., correlates
Fleming's right-hand rule regarding direction of induced e.m.f., correlates
To achieve sparkless commutation brushes of a D.C. generator are rockedm ahead so as to bring them
To achieve sparkless commutation brushes of a D.C. generator are rockedm ahead so as to bring them
Welding generator will have
Welding generator will have
In a level compounded D.C. generator, full load terminal voltage is
In a level compounded D.C. generator, full load terminal voltage is
In D.C. generators, lap winding is used for
In D.C. generators, lap winding is used for
The terminal voltage of a series generator is 150 V when the load current is 5 A. If the load current is increased to 10 A, the terminal voltage will be
The terminal voltage of a series generator is 150 V when the load current is 5 A. If the load current is increased to 10 A, the terminal voltage will be
In D.C. generators, the brushes on commutator remain in contact with conductors which
In D.C. generators, the brushes on commutator remain in contact with conductors which
Two generators A and B have 6 poles each. Generator A has wave wound armature while generator B has lap wound armature. The ratio of the induced e.m.f. is generator A and B will be
Two generators A and B have 6 poles each. Generator A has wave wound armature while generator B has lap wound armature. The ratio of the induced e.m.f. is generator A and B will be
For a D.C. machines laboratory following type of D.C. supply will be suitable
For a D.C. machines laboratory following type of D.C. supply will be suitable
Copper brushes in D.C. machine are used
Copper brushes in D.C. machine are used
In a D.C. generator the critical resistance can be increased by
In a D.C. generator the critical resistance can be increased by
Which generator would you prefer for feeding long D.C. transmission lines?
Which generator would you prefer for feeding long D.C. transmission lines?
To avoid formation of grooves in the commutator of a D.C. machine
To avoid formation of grooves in the commutator of a D.C. machine
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
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
Flashing the field of D.C. generator means
Flashing the field of D.C. generator means
In a commutator
In a commutator
The critical resistance of the D.C. generator is the resistance of
The critical resistance of the D.C. generator is the resistance of
The number of brushes in a commutator depends on
The number of brushes in a commutator depends on
In D.C. generators the pole shoes are fastened to the pole core by
In D.C. generators the pole shoes are fastened to the pole core by
A D.C. generator works on the principle of
A D.C. generator works on the principle of
In a D.C. generator the ripples in the direct e.m.f. generated are reduced by
In a D.C. generator the ripples in the direct e.m.f. generated are reduced by
A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be
A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be
D.C. generators are connected to the bus-bars or disconnected from them only under the floating condition
D.C. generators are connected to the bus-bars or disconnected from them only under the floating condition
Which of the following D.C. generators will be in a position to build up without any residual magnetism in the poles ?
Which of the following D.C. generators will be in a position to build up without any residual magnetism in the poles ?
The following constitute short-circuit in the armature winding.
The following constitute short-circuit in the armature winding.
D.C. generator generally preferred for charging automobile batteries is
D.C. generator generally preferred for charging automobile batteries is
The resistance of armature winding depends on
The resistance of armature winding depends on
The terminal voltage of a D.C. shunt generator drops on load because of all of the following reasons except
The terminal voltage of a D.C. shunt generator drops on load because of all of the following reasons except
For both lap and wave windings, there are as many commutator bars as the number of
For both lap and wave windings, there are as many commutator bars as the number of
Permeance is the reciprocal of
Permeance is the reciprocal of
The commutator segments are connected to the armature conductors by means of
The commutator segments are connected to the armature conductors by means of
With a D.C. generator which of the following regulation is preferred?
With a D.C. generator which of the following regulation is preferred?
A separately excited generator as compared to a self-excited generator
A separately excited generator as compared to a self-excited generator
In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when
In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when
The material for commutator brushes is generally
The material for commutator brushes is generally
Armature reaction of an unsaturated D.C. machine is
Armature reaction of an unsaturated D.C. machine is
In over compounded generator, full load terminal voltage is
In over compounded generator, full load terminal voltage is
If a D.C. generator fails to build up the probable cause could not be
If a D.C. generator fails to build up the probable cause could not be
A shunt generator can self-excite
A shunt generator can self-excite
In any rotating machine that part which houses the conductors and in which e.m.f. induced is to be utilized is called
In any rotating machine that part which houses the conductors and in which e.m.f. induced is to be utilized is called
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.
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.
Two generators are running in parallel. One of the generators may run as motor for which of the following reasons?
Two generators are running in parallel. One of the generators may run as motor for which of the following reasons?
In case of a 4 pole D.C. generator provided with a two layer lap winding with sixteen coils, the pole pitch will be
In case of a 4 pole D.C. generator provided with a two layer lap winding with sixteen coils, the pole pitch will be
If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be
If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be
Armature reaction in a generator results in
Armature reaction in a generator results in
Lap winding is composed of
Lap winding is composed of
A D.C. welding generator has
A D.C. welding generator has
The demagnetizing component of armature reaction in a D.C. generator
The demagnetizing component of armature reaction in a D.C. generator
Equalizer rings are required in case armature is
Equalizer rings are required in case armature is
A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly
A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly
The armature core of a D.C. generator is usually made of
The armature core of a D.C. generator is usually made of
The function of pole shoes in the case of D.C. machine is
The function of pole shoes in the case of D.C. machine is
In a D.C. generator the actual flux distribution depends upon
In a D.C. generator the actual flux distribution depends upon
Armature coil is short circuited by brushes when it lies
Armature coil is short circuited by brushes when it lies
In the case of lap winding resultant pitch is
In the case of lap winding resultant pitch is
When two D.C. series generators are running in parallel, an equalizer bar is used
When two D.C. series generators are running in parallel, an equalizer bar is used
D.C. series generator is used
D.C. series generator is used
The series field of a short-shunt D.C. generator is excited by
The series field of a short-shunt D.C. generator is excited by
Which of the following generating machine will offer constant voltage on all loads?
Which of the following generating machine will offer constant voltage on all loads?
Brushes of D.C. machines are made of
Brushes of D.C. machines are made of
Eddy currents are induced in the pole shoes of a D.C. machine due to
Eddy currents are induced in the pole shoes of a D.C. machine due to
Iron losses in a D.C. machine are independent of variations in
Iron losses in a D.C. machine are independent of variations in
Two D.C. shunt generators, each with armature resistance of 0.02 ohm and field resistance of 50 ohm run in parallel and supply a total current of 1000 amperes to the load circuit. If their e.m.fs. are 270 V and 265 V, their bus bar voltage will be
Two D.C. shunt generators, each with armature resistance of 0.02 ohm and field resistance of 50 ohm run in parallel and supply a total current of 1000 amperes to the load circuit. If their e.m.fs. are 270 V and 265 V, their bus bar voltage will be
In any rotating machine that part which houses the conductors and in which e.m.f. induced is to be utilised is called
In any rotating machine that part which houses the conductors and in which e.m.f. induced is to be utilised is called
In lap winding, the number of brushes is always
In lap winding, the number of brushes is always
Following D.C. generator will be in a position to build up without any residual magnetism in the poles
Following D.C. generator will be in a position to build up without any residual magnetism in the poles
In a D.C. generator in case the resistance of the field winding is increased, then output voltage will
In a D.C. generator in case the resistance of the field winding is increased, then output voltage will
Wave winding is composed of
Wave winding is composed of
If B is the flux density, I the length of conductor and v the velocity of conductor, then induced e.m.f. is given by
If B is the flux density, I the length of conductor and v the velocity of conductor, then induced e.m.f. is given by
In a D.C. machine, short-circuited field coil will result in
In a D.C. machine, short-circuited field coil will result in
Which of the following components of a D.C, generator plays vital role for providing direct current of a D.C. generator?
Which of the following components of a D.C, generator plays vital role for providing direct current of a D.C. generator?
The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be
The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be
Which of the following statement about D.C. generators is false?
Which of the following statement about D.C. generators is false?
The field coils of D.C. generator are usually made of
The field coils of D.C. generator are usually made of
When two D.C. generators are running in parallel an equalizer bar is used
When two D.C. generators are running in parallel an equalizer bar is used
Magnetic field in a D.C. generator is produced by
Magnetic field in a D.C. generator is produced by
The armature of D.C. generator is laminated to
The armature of D.C. generator is laminated to
