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D.C. generators are installed near the load centres to reduce line losses.

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Answer : D.C. generators are connected to the busbars or disconnected from them only under the floating condition to avoid sudden loading of the primemover, to avoid mechanicaljerk to the shaft, to avoid burning of switch contacts.

Answer : In D.C. generators the pole shoes are fastened to the pole core by counter sunk screws.

Answer : If  equalising bar is connected to the 2 DC generators  the current will be equal in 2 generators irrespective of parallel connection so that we connect equaliser bar

Answer : Compensating windings are used in D.C. generators to neutralise the cross-magnetising effect of the armature reaction.

Answer : D.C. generators are normally designed for maximum efficiency around full-load.

Answer : In D.C. generators, current to the external circuit from armature is given through commutator commutator.

Answer : In D.C. generators the polarity of the interpoles is the same as that of the main pole ahead.

Answer : For the parallel operation of two or more D.C. compound generators, we should ensure that series fields of all generators should be either on positive side or negative side of the armature.

Answer : In D.C. generators, the brushes on commutator remain in contact with conductors which lie under interpolar region.

Description : Identify the increasing order of voltage regulation of the following dc generators a same load :  (A) differential compound, shunt and under compound  (B) shunt, differential compound and ... C) under compound, shunt and differential compound  (D) shunt, under compound and differential compound

Answer : Identify the increasing order of voltage regulation of the following dc generators a same load : under compound, shunt and differential compound 

Description : In DC generators lamination core are generally made of?

Answer : In DC generators lamination core are generally made of silicon steel.

Answer : Generators for peak load plants are usually designed for maximum efficiency at 50 to 75 percent full load.

Answer : In D.C. generators on no-load, the air gap flux distribution in space is flat topped.

Description : Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power characteristics have a common slope of 1 MW/Hz and the no-load frequencies of the generators are 51.5 Hz and 51.0 Hz, ... system frequency is (A) 50 Hz (B) 51 Hz (C) 51.25 Hz (D) 51.5 Hz

Answer : Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power characteristics have a common slope of 1 MW/Hz and the no-load frequencies of the generators are 51.5 Hz and 51.0 Hz, respectively. Then the system frequency is 50 Hz

Description : Why are generators rated in kVA not in kW ?

Answer : Because It's rating of generator kva is apparent power. Kw is active power which we use. And one is kvar reactive power.

Description : Two synchronous generators G1, G2 are operating in parallel and are equally sharing KVAR (Lag) component of load. To shift part of KVAR from G2 to G1, while keeping terminal voltage fixed, the following action must be done

Answer : Two synchronous generators G1, G2 are operating in parallel and are equally sharing KVAR (Lag) component of load. To shift part of KVAR from G2 to G1, while keeping terminal voltage fixed, the following action must be done Raise If1 and lower If2

Answer : Large capacity generators are invariably hydrogen cooled.

Answer : In a level compounded D.C. generator, full load terminal voltage is equal to no-load terminal voltage.

Description : Eddy currents are induced in the pole shoes of a D.C. machine due to?

Answer : Eddy currents are induced in the pole shoes of a D.C. machine due to relative rotation between field and armature.

Answer : If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be crossmagnetisation as well as demagnetising.

Answer : In a D.C. generator the ripples in the direct e.m.f. generated are reduced by using carbon brushes of superior quality.

Answer : Brushes of D.C. machines are made of carbon.

Answer : Iron losses in a D.C. machine are independent of variations in load.

Answer : Flywheel is used with D.C. compound motor to reduce the peak demand by the motor, compound motor will have to be cumulatively compounded.

Answer : To avoid formation of grooves in the commutator of a D.C. machine the brushes of opposite polarity should track each other.

Answer : In a D.C. generator, the critical resistance refers to the resistance of field.

Answer : If a D.C. generator fails to build up the probable cause could not be field resistance less than the critical resistance.

Answer : The e.m.f. generated in a D.C. generator is directly proportional to speed of armature.

Answer : In case of D.C. machine winding, number of commutator segments is equal to number of armature coils.

Answer : The purpose of retardation test on D.C. shunt machines is to find out stray losses.

Answer : The critical resistance of the D.C. generator is the resistance of field.

Description : If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be?

Answer : If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be zero.

Answer : A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be about 2 V.

Answer : In a D.C. generator in case the resistance of the field winding is increased, then output voltage will decrease.

Answer : In a D.C. machine stray loss is the sum of iron loss and mechanical loss.

Answer : A D.C. generator can be considered as rotating amplifier.

Answer : Flashing the field of D.C. generator means creating residual magnetism by a D.C. source.

Answer : In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis, when there is no load on|he generator.

Answer : In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when number of poles is 2.

Answer : D.C. generator generally preferred for charging automobile batteries is long shunt compound generator.

Answer : Open circuited armature coil of a D.C. machine is identified by the scarring of the commutator segment to which open circuited coil is connected and indicated by a spark completely around the commutator.

Answer : Satisfactory commutation of D.C. machines requires brushes should be of proper grade and size, brushes should smoothly run in the holders, smooth, concentric commutator properly undercut.

Answer : The armature core of a D.C. generator is usually made of silicon steel.

Answer : Magnetic field in a D.C. generator is produced by electromagnets.

Answer : The demagnetising component of armature reaction in a D.C. generator reduces generator e.m.f.

Answer : In case of a 4-pole D.C. generator provided with a two layer lap winding with sixteen coils, the pole pitch will be 8.

Answer : In a four-pole D.C. machine alternate poles are north and south.

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