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Answer :

When a conductor carries more current on the surface as compared to core, it is due to skin effect.

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Last Answer : Following are requirements of conductor:- i) High conductivity :  Material should have high conductivity, So that * cross section of conductor (size) reduces, * Copper losses reduces, * So Efficiency ... . Boiling point is 1820°C 9. Specific gravity is 2.7 10. High resistance to corrosion. 

Description : How does the resistance of a conductor compare to that of an insulator?

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Description : When electric current passes through a metallic conductor, its temperature rises. This is due to?

Last Answer : When electric current passes through a metallic conductor, its temperature rises. This is due to collisions between conduction electrons and atoms.

Description : Heat in a conductor is produced on the passage of electric current due to?

Last Answer : Heat  in  a   conductor  is  produced   due  to  frictional  collision  of  electrons   flow  as  they  conduct  current.

Description : A ferrite core has less eddy current loss than an iron core because?

Last Answer : A ferrite core has less eddy current loss than an iron core because ferrites have high hysteresis.

Description : When secondary of a current transformer is open-circuited its iron core will be?

Last Answer : When secondary of a current transformer is open-circuited its iron core will be hot because of heavy iron losses taking place in it due to high flux density.

Description : The insulation on a current carrying conductor is provided?

Last Answer : The insulation on a current carrying conductor is provided to prevent leakage of current, to prevent shock.

Description : How to find total impedance Z, current I and Impedance angle ?

Last Answer : How to find total impedance Z, current I and Impedance angle ?

Description : Is Aluminium a good conductor of electricity?

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Description : Why ACSR conductor is used for overhead lines?

Last Answer : It has high tensile strength 

Description : Define surface tension. State its S.I. unit.

Last Answer : Definition:- The force acting per unit length of an imaginary line drawn to surface of liquid.  OR  The surface tension is defined as the property of liquids by virtue of which the surface of a liquid is ... due to the tendency to contract and occupy minimum surface area.  S.I. unit :- N/m

Description : State the significance of following terms : i) Hydrology ii) Surface run-off iii) Evaporation iv) Precipitation

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Description : In an AC. circuit, a low value of kVAR compared with kW indicates?

Last Answer : In an AC. circuit, a low value of kVAR compared with kW indicates high power factor.

Last Answer : In main line service as compared to urban and suburban service distance between the stops is more, maximum speed reached is high, acceleration and retardation rates are low.

Last Answer : A.C. series motor as compared to D.C. series motor has smaller brush width, less number of field turns, more number of armature turns, less air gap.

Last Answer : An alternator coupled to a hydraulic turbine runs at slow speed, as compared to others.

Last Answer : H.R.C. fuse, as compared to a rewirable fuse, has no ageing effect, high speed of operation, high rupturing capacity.

Description : In an alternator at lagging power factor the generated voltage per phase as compared to that at unity power factor?

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Description : Which have more free electrons: conductors or insulators? 

Last Answer : Conductors have many free electrons whereas insulators have very few or none at all.

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Description : About trnsformer

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Description : State the material used for making (1) Magnetic Core (2) Fuse element  

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Description : State any four characteristics of core type transformer.

Last Answer : Characteristics of core type transformer: i) It has one window. ii) It has one magnetic circuit. iii) Core surrounds the winding. iv) Average length of core is more. v) Area of cross ... Better cooling for winding. vii) Mechnical strength is comparatively less. viii) Repair and maintenance is easy.

Description : A 40 kVA transformer has a core loss of 400 W and a full load copper loss of 800 W. The proportion of full load at maximum efficiency is

Last Answer : A 40 kVA transformer has a core loss of 400 W and a full load copper loss of 800 W. The proportion of full load at maximum efficiency is 0.707

Description : The core construction is like spokes of a wheel in following transformer:  (A) Berry Type Transformer (B) Core Type Transformer (C) Shell Type Transformer (D) None of the above

Last Answer : The core construction is like spokes of a wheel in following transformer:  Berry Type Transformer

Description : Core type transformers are popular in___________.  (A) High voltage applications (B) Low voltage applications (C) All of the above (D) None of the above

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Description : The desirable properties of transformer core material are  (1) low permeability and low hysteresis loss. (2) high permeability and high hysteresis loss. (3) high permeability and low hysteresis loss. (4) low permeability and hysteresis loss.

Last Answer : The desirable properties of transformer core material are high permeability and low hysteresis loss.

Description : A single core lead sheathed cable with two dielectrics of permittivity 4 and 3, respectively, are subjected to same maximum stress. If the conductor diameter is 1.5 cm, the outer diameter of the first dielectric is (A) 1.125 cm (B) 1.5 cm (C ) 2 cm (D) 8 cm

Last Answer : A single core lead sheathed cable with two dielectrics of permittivity 4 and 3, respectively, are subjected to same maximum stress. If the conductor diameter is 1.5 cm, the outer diameter of the first dielectric is 2 cm 

Description : A single core cable is designed to work for a single phase system with a peak voltage of 220 kV. The maximum permissible stress in the dielectric is not to exceed 20 kV/mm. For economical size, the overall core diameter of the cable is (A) 28.2 mm (B) 26.4 mm (C) 24.4 mm (D) 22.0 mm

Last Answer : A single core cable is designed to work for a single phase system with a peak voltage of 220 kV. The maximum permissible stress in the dielectric is not to exceed 20 kV/mm. For economical size, the overall core diameter of the cable is 22.0 mm

Description : The main purpose of using core in a transformer is to (A) decrease iron losses (B) eliminate magnetic hysteresis (C) reduce reluctance of the common magnetic circuit (D) prevent eddy current loss

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

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Description : The size of a transformer core will depend on?

Last Answer : The size of a transformer core will depend on frequency and area of the core.

Description : Reduction in core losses and increase in permeability are obtained with transformer employing?

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Description : Why does the core of a transformer need to be laminated?

Last Answer : Transformer cores are laminated to reduce eddy current loss.

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

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Last Answer : Transformer core is laminated to reduce Eddy current losses.

Description : State properties of conductor material used for overhead conductor. 

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Last Answer : Which allows the flow electrons 

Description : reasons the transposition of conductor

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Description : What is difference between Conductor and insulator ?

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Last Answer : Silver is the best conductor. Carbon is the semiconductor. Iron have less conductance as compared to silver.

Description : In a metal conductor, what is a free electron?

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Last Answer : A 3 layer, total diameter of an ACSR conductor is 5 cm. Find the diameter of each strand? 1 cm

Description : lf the wire which is vertical to this page has electron flow downwards the conductor will have

Last Answer : lf the wire which is vertical to this page has electron flow downwards the conductor will have a counter-clockwise field in the plane of the paper

Description : The thickness of insulation provided on the conductor depends on?

Last Answer : The thickness of insulation provided on the conductor depends on the magnitude of voltage on the conductor.

Description : If a wire conductor of 0.2 ohm resistance is doubled in length, its resistance becomes?

Last Answer : If a wire conductor of 0.2 ohm resistance is doubled in length, its resistance becomes 0.4 ohm.

Description : The resistance of a few meters of wire conductor in closed electrical circuit is?

Last Answer : The resistance of a few meters of wire conductor in closed electrical circuit is practically zero.

Description : The resistance of a conductor varies inversely as?

Last Answer : The resistance of a conductor varies inversely as area of cross-section.