The breakdown of insulation of the cable can be avoided economically by the use of (a) inter-sheaths (b) insulating materials with different dielectric constants (c) both (a) and (b) (d) none of the above

The breakdown of insulation of the cable can be avoided economically by the use of (a) inter-sheaths (b) insulating materials with different dielectric constants (c) both (a) and (b) (d) none of the above
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1 Answer

Answer :

(c) both (a) and (b)
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Related questions

In the cables, sheaths are used to (a) prevent the moisture from entering the cable (b) provide enough strength (e) provide proper insulation (d) none of the above

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Last Answer : (a) prevent the moisture from entering the cable

The insulating material for a cable should have (a) low cost (b) high dielectric strength (c) high mechanical strength (d) all of the above

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If a cable of homogeneous insulation has a maximum stress of 10 kV/mm, then the dielectric strength of insulation should be (a) 5 kV/mm (b) 10 kV/mm (a) 15 kV/mm (d) 30 kV/mm

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Last Answer : (b) 10 kV/mm

The insulating material should have (a) low permittivity (b) high resistivity (c) high dielectric strength (d) all of the above

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Solid type cables are considered unreliable beyond 66 kV because (a) insulation may melt due to higher temperature (b) skin effect dominates on the conductor (c) of corona loss between conductor and sheath material (d) there is a danger of breakdown of insulation due to the presence of voids

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Description : How armours /sheaths grounded? 

Last Answer : 1 core cables -- sheaths/shields/armours grounded at one end only, other end insulated to prevent the circulating current through sheaths. 3 core cables -- grounded at both ends but not including core balance CT’s, since even small induced current causes 50N operation. 

The minimum dielectric stress in a cable is at (a) armour (b) bedding (c) conductor surface (d) lead sheath

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The breakdown voltage of a cable depends on (a) presence of moisture (b) working temperature (c) time of application of the voltage (d) all of the above

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The insulation of the cable decreases with (a) the increase in length of the insulation (b) the decrease in the length of the insulation (c) either (a) or (b) (d) none of the above

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A certain cable has an insulation of relative permittivity 4. If the insulation is replaced by one of relative permittivity 2, the capacitance of the cable will become (a) one half (6) double (c) four times (d) none of the above

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The disadvantage with paper as insulating material is (a) it is hygroscopic (6) it has high capacitance (c) it is an organic material (d) none of the above

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The insulating material for cables should (a) be acid proof (b) be non-inflammable (c) be non-hygroscopic (d) have all above properties

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In capacitance grading of cables we use a ______ dielectric. (a) composite (b) porous (c) homogeneous (d) hygroscopic

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Polyethylene has very poor dielectric and ageing properties. (a) Yes (b) No

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In capacitance grading a homogeneous dielectric is used. (a) Yes (b) No

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Dielectric strength of rubber is around (a) 5 kV/mm (b) 15 kV/mm (c) 30 kV/mm (d) 200 kV/mm

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What are the disadvantages of paper insulation?

Description : What are the disadvantages of paper insulation? 

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Rubber is most commonly used insulation in cables. (a) Yes (b) No

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The intersheaths in the cables are used to (a) minimize the stress (b) avoid the requirement of good insulation (c) provide proper stress distribution (d) none of the above

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The thickness of the layer of insulation on the conductor, in cables, depends upon (a) Reactive power (b) Power factor (c) Voltage (d) Current carrying capacity

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Which of the following insulation is used in cables? (a) Varnished cambric (b) Rubber (c) Paper (d) Any of the above

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What is the specified cable life?

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If a power cable and a communication cable are to run parallel the minimum distance between the two, to avoid interference, should be (a) 2 cm (b) 10 cm (c) 50 cm (d) 400 cm

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In a cable the voltage stress is maximum at (a) sheath (6) insulator (e) surface of the conductor (d) core of the conductor

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In case of three core flexible cable the colour of the neutral is (a) blue (b) black (c) brown (d) none of the above

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In a cable immediately above metallic sheath _____ is provided. (a) Earthing connection (b) Bedding (c) Armouring (d) None of the above

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Indicate the three types oftransmissionline energylosses. a. I2R, R , and temperature b. Radiation, I2R, and dielectric heating c. Dielectric separation, insulation breakdown, and radiation d. Conductor heating, dielectric heating, and radiation resistance.

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Materials, which provide a path to the magnetic flux, are classified as (A) insulating materials. (B) semi conducting materials. (C) magnetic materials. (D) dielectric materials.

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