The condition for maximum efficiency for a D.C. generator is?

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1 Answer

Answer :

The condition for maximum efficiency for a D.C. generator is variable losses equal to constant losses.

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D.C. generators are normally designed for maximum efficiency around?

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

Generators for peak load plants are usually designed for maximum efficiency at?

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

An ideal transformer will have maximum efficiency at a load such that?

Last Answer : An ideal transformer will have maximum efficiency at a load such that copper loss equal to iron loss.

For a transformer, operating at constant load current, maximum efficiency will occur at?

Description : For a transformer, operating at constant load current, maximum efficiency will occur at?

Last Answer : For a transformer, operating at constant load current, maximum efficiency will occur at unity power factor.

when will be the maximum efficiency of transformer?

Last Answer : Transformer efficiency is maximum when copper losses are equal to iron losses.

The critical resistance of the D.C. generator is the resistance of?

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

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

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

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

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

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

In a level compounded D.C. generator, full load terminal voltage is?

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

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

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

A D.C. generator can be considered as?

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

In a D.C. generator the critical resistance refers to the resistance of?

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

Flashing the field of D.C. generator means?

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

If a D.C. generator fails to build up the probable cause could not be?

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

In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis, when?

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

The e.m.f. generated in a D.C. generator is directly proportional to?

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

In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when?

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

D.C. generator generally preferred for charging automobile batteries is?

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

The armature core of a D.C. generator is usually made of?

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

In a D.C. generator the ripples in the direct e.m.f. generated are reduced by?

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

The demagnetising component of armature reaction in a D.C. generator?

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

If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be?

Last 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.

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

Last 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.

For a D.C. generator when the number of poles and the number of armature conductors is fixed...

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In a D.C. generator, the iron losses mainly take place in?

Last Answer : In a D.C. generator, the iron losses mainly take place in armature rotor.

The total losses in a well designed D.C. generator of 10 kW will be nearly?

Last Answer : The total losses in a well designed D.C. generator of 10 kW will be nearly 500 W.

In D.C. generators on no-load, the air gap flux distribution in space is?

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

State maximum power transfer theorem for DC circuit.

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Last Answer : Maximum power transfer theorem for DC circuit: The maximum power transfer theorem states that the source or a network transfers maximum power to load only when the load resistance is equal ... removed (disconnected) ii) All internal independent sources are replaced by their internal resistances.

Which D.C. motor has got maximum self relieving property ?

Last Answer : Series motor has got maximum self relieving property.

In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will be?

Last Answer : In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will be more than full-load current.

State the function of commutator in DC generator and name the material used for commutator.

Description : State the function of commutator in DC generator and name the material used for commutator.

Last Answer : Function of Commutator: Commutator converts AC induced in armature winding into DC for external load. Material: i) Commutator segments are made up of Copper. ii) Commutator segments are insulated from each other by Mica.

A 200 V DC machine supplies 20 A at 200 V as a generator. The armature resistance is 0.2

Description : A 200 V DC machine supplies 20 A at 200 V as a generator. The armature resistance is 0.2 Ohm. If the machine is now operated as a motor at same terminal voltage and current but with the flux increased by 10%, the ratio of motor speed to generator speed is

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The fall in speed of a dc generator due to increase in load can be corrected by

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The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density.

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In a DC generator the windings of interpoles are connected :

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Last Answer : In a DC generator the windings of interpoles are connected :  in series with the armature winding, to create a pole of same polarity as the main pole ahead in the direction of rotation. 

The terminal characteristics of a dc generator suitable for electric welders is

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What is the difference between an AC and DC generator?

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Last Answer : The generator which generates DC voltage is called DC generator and generator which generates AC voltage is called AC generator (or) Alternator. In DC generator armature is rotated and field winding ... generator. A DC generator can generate low voltages but an AC generator can generate upto 11kv.

What is the principle of DC generator?

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From which material field coils of DC generator are made of?

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Why is the armature of DC generator laminated?

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Armature reaction in a generator results in?

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In a separately excited generator supplying rated load the armature reaction?

Last Answer : In a separately excited generator supplying rated load the armature reaction is always present.

A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave?

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Last Answer : A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave will be of 5 Hz.

In over compounded generator, full load terminal voltage is?

Last Answer : In over compounded generator, full load terminal voltage is more than no load terminal voltage.

In case of a flat compounded generator?

Last Answer : In case of a flat compounded generator voltage remains constant irrespective of the load.