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

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

Last Answer : 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 0.87

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

Description : The fall in speed of a dc generator due to increase in load can be corrected by (1) cooling the armature.. (2) increasing the excitation. (3) reducing the load voltage. (4) increasing the input to the prime mover

Last Answer : It can be corrected by increasing the input to the prime mover.

In a DC generator the windings of interpoles are connected :

Description : In a DC generator the windings of interpoles are connected : (A) in series with main field winding, to create a pole,of same polarity as the main pole ahead in the direction of rotation. ... winding, to create a pole of opposite polarity as the main pole ahead in the direction of rotation.

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.

What is the difference between an AC and DC generator?

Description : What is the difference between an AC and DC generator?

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?

Description : What is the principle of DC generator?

Last Answer : principle

Why is the armature of DC generator laminated?

Description : Why is the armature of DC generator laminated?

Last Answer : The armature of DC generator is laminated to reduce eddy current losses.

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

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

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 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.

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.

If the field of a D.C. shunt motor gets opened while motor is running?

Last Answer : If the field of a D.C. shunt motor gets opened while motor is running the motor will attain dangerously high speed.

In a A.C. series motor armature coils are usually connected to commutator?

Last Answer : In a A.C. series motor armature coils are usually connected to commutator through resistance.

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

Description : The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density. When frequency is increased to 50 Hz., eddy current loss is : (A) 256 W (B) 320 W (C) 500 W (D) 625 W

Last Answer : The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density. When frequency is increased to 50 Hz., eddy current loss is : 625 W

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

Description : The terminal characteristics of a dc generator suitable for electric welders is (A) separately excited generator (B) shunt generator (C) series generator (D) differentially compounded generator

Last Answer : The terminal characteristics of a dc generator suitable for electric welders is differentially compounded generator

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.

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.

If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens?

Last Answer : If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens this will make armature to take heavy current, possibly burning it.

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.

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.

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.

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.

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

Description : 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. ?

Last Answer : Wave winding

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

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

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.

The two pressure coils of a single phase power factor meter have?

Last Answer : The two pressure coils of a single phase power factor meter have the same dimensions and the same number of turns.

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.

The rotor of a hysteresis motor is made of?

Last Answer : The rotor of a hysteresis motor is made of chrome steel.

The field coils of D.C. generator are usually made of (a) mica (b) copper (c) cast iron (d) carbon

Description : The field coils of D.C. generator are usually made of (a) mica (b) copper (c) cast iron (d) carbon

Last Answer : Ans: b (b) copper

In a synchronous machine, if the field flux axis ahead of the armature field axis in the direction of rotation,

Description : In a synchronous machine, if the field flux axis ahead of the armature field axis in the direction of rotation, the machine is operating as (1) synchronous motor (2) synchronous generator (3) asynchronous motor (4) asynchronous generator

Last Answer : In a synchronous machine, if the field flux axis ahead of the armature field axis in the direction of rotation, the machine is operating as synchronous generator

A _________ is used to measure the stator % winding temperature of the generator.

Description : A _________ is used to measure the stator % winding temperature of the generator. (A) Thermocouple (B) Pyrometer (C) Resistance thermometer (D) Thermometer

Last Answer : A Resistance thermometer is used to measure the stator % winding temperature of the generator.

In a synchronous generator if the excitation increased from a low value to normal value, with a fixed load

Description : In a synchronous generator if the excitation increased from a low value to normal value, with a fixed load (A) The armature current increases and the power factor decreases (B) The armature ... but is lagging (D) The armature current decreases and the power factor increases and is leading

Last Answer : In a synchronous generator if the excitation increased from a low value to normal value, with a fixed load The armature current decreases and the power factor increases and is leading

In a synchronous generator delivering lagging power factor load

Description : In a synchronous generator delivering lagging power factor load (1) the excitation emf leads terminal voltage by the power angle (2) the excitation emf lags terminal voltage by the power angle (3) ... by the power factor angle (4) excitation emf lags the terminal voltage by the power factor angle

Last Answer : In a synchronous generator delivering lagging power factor load the excitation emf leads terminal voltage by the power angle

The armature reaction in a synchronous generator supplying leading power factor load is

Description : The armature reaction in a synchronous generator supplying leading power factor load is (A) magnetizing (B) demagnetizing (C) demagnetizing and cross-magnetizing (D) magnetizing and cross-magnetizing

Last Answer : The armature reaction in a synchronous generator supplying leading power factor load is magnetizing and cross-magnetizing

What are the main parts of a generator?

Description : What are the main parts of a generator?

Last Answer : the main parts of the generator are as follows yoke Armature Poles field winding Prime mover Commutator Shaft Bearings Brushes

can induction motor be used as generator?

Last Answer : if induction motor rotates exceed than its synchronous speed, it acts as a generator.

anonymous · Answer 1 · 2018-03-03T01:47:54+0000

Field coils of DC generator are usually made of copper.

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

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