1. An isolator is a device design to operates on
(a) no load.
(b) normal condition.
(c) full load.
(d) none of the above.
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2. A circuit breaker is a device used to
(a) limit the current.
(b) interrupt the circuit.
(c) detect the fault current.
(d) control the fault current.
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3. In power system, the function of relay is to
(a) limit the current.
(b) control the fault current.
(c) detect the fault current.
(d) interrupt the circuit.
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4. The rating of a fuse is expressed in terms of
(a) Ampere.
(b) Volt.
(c) VAR.
(d) Watt.
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5. Which material is used in liquid fuses ?
(a) SF6.
(b) distilled water.
(c) carbon tetra chloride.
(d) transformer oil.
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6. The capacitor switching is easily done with
(a) oil circuit breaker.
(b) air blast circuit breaker.
(c) vacuum circuit breaker.
(d) any one of these.
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7. Which of the following relay is used for phase fault protection of short transmission lines ?
(a) Reactance relay.
(b) Impedance relay.
(c) mho relay.
(d) IDMT relay.
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8. Which of the following relay is used for phase fault protection of medium transmission lines ?
(a) Reactance relay.
(b) Impedance relay.
(c) mho relay.
(d) IDMT relay.
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9. Which of the following relay is used for phase fault protection of long transmission lines ?
(a) Reactance relay.
(b) Impedance relay.
(c) mho relay.
(d) IDMT relay.
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10. Directional relays work on the bases of flow of
(a) frequency.
(b) power.
(c) current.
(d) voltage wave.
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11. H.R.C. fuses provide best protection against
(a) overload.
(b) reverse current.
(c) open-circuits.
(d) short-circuits.
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12. Which of the following circuit breaker produce least arc energy?
(a) Air blast CB
(b) Air break CB.
(c) Minimum oil CB.
(d) Plain oil CB.
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13. In HRC Fuse, the fuse element is mainly made up of
(a) copper.
(b) aluminium.
(c) silver.
(d) lead tin alloy.
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14. A material best suited for manufacturing of fuse wire is
(a) Aluminium.
(b) Silver.
(c) Lead.
(d) Copper.
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15. The end caps used in HRC fuses are made by
(a) porcelain.
(b) brass.
(c) manganin.
(d) nichrome.
Answer