1. Arc in a circuit breaker is interrupted at
(A) zero current.
(B) maximum current.
(C) minimum voltage.
(D) maximum voltage.
[accordion clicktoclose=true tag=h4][accordion-item title=”Answer ⇓” state=closed] A [/accordion-item][/accordion]
2. Induction cup relay operates when there is changes in
(A) voltage.
(B) current.
(C) impedance.
(D) all of the above.
[accordion clicktoclose=true tag=h4][accordion-item title=”Answer ⇓” state=closed] D [/accordion-item][/accordion]
3. The arcing contacts in a circuit breaker are generally made of
(A) lead tin alloy.
(B) copper tungsten alloy.
(C) electrolytic copper.
(D) aluminium alloy.
[accordion clicktoclose=true tag=h4][accordion-item title=”Answer ⇓” state=closed] B [/accordion-item][/accordion]
4. The operating time of a fuse is nearly
(A) 1 sec.
(B) 0.5 sec.
(C) 1.8 sec.
(D) 0.002 sec.
[accordion clicktoclose=true tag=h4][accordion-item title=”Answer ⇓” state=closed] D [/accordion-item][/accordion]
5. The operating time of a circuit breaker is nearly
(A) 0.004 sec.
(B) 1.04 sec.
(C) 0.02 sec.
(D) 0.2 sec.
[accordion clicktoclose=true tag=h4][accordion-item title=”Answer ⇓” state=closed] D [/accordion-item][/accordion]
6. The application of a Volt/Hertz relay is in
(A) over excited protection.
(B) backup protection.
(C) over voltage protection.
(D) anti motoring protection.
[accordion clicktoclose=true tag=h4][accordion-item title=”Answer ⇓” state=closed] A [/accordion-item][/accordion]
7. The shape of the disc of an induction disc relay is
(A) square.
(B) spiral.
(C) circular.
(D) elliptical.
[accordion clicktoclose=true tag=h4][accordion-item title=”Answer ⇓” state=closed] B [/accordion-item][/accordion]
8. The breaking capacity of a fuse is
(A) zero.
(B) small.
(C) high.
(D) infinite.
[accordion clicktoclose=true tag=h4][accordion-item title=”Answer ⇓” state=closed] B [/accordion-item][/accordion]
9. In a thermal relay, a bi-metal strip consists of two metal strips having different
(A) thermal conductivity.
(B) efficient of expansion.
(C) specific heat.
(D) all of the above.
[accordion clicktoclose=true tag=h4][accordion-item title=”Answer ⇓” state=closed] B [/accordion-item][/accordion]
10. Differential relay are used to protect the equipment against
(A) external faults.
(B) over current.
(C) reverse current .
(D) internal faults.
[accordion clicktoclose=true tag=h4][accordion-item title=”Answer ⇓” state=closed] D [/accordion-item][/accordion]
11. Distance Protection Scheme is used for the protection of
(A) motor.
(B) transformer.
(C) alternator.
(D) overhead line.
[accordion clicktoclose=true tag=h4][accordion-item title=”Answer ⇓” state=closed] D [/accordion-item][/accordion]
12. In transmission lines, the capacitance as compared to inductance is
(A) very small.
(B) very large .
(C) equal.
(D) double.
[accordion clicktoclose=true tag=h4][accordion-item title=”Answer ⇓” state=closed] A [/accordion-item][/accordion]
13. Shunt compensation in an EHV line is used to improve
(A) stability and fault level.
(B) fault level and voltage profile.
(C) voltage profile and stability.
(D) stability, fault level and voltage profile.
[accordion clicktoclose=true tag=h4][accordion-item title=”Answer ⇓” state=closed] B [/accordion-item][/accordion]
14. Thermal relays are used for protection of motor against over-current owing to
(A) short-circuits.
(B) earth fault.
(C) heavy load.
(D) All of the above.
[accordion clicktoclose=true tag=h4][accordion-item title=”Answer ⇓” state=closed] C [/accordion-item][/accordion]
15. Which of the following circuit breaker preferred for high voltage and low current interruption ?
(A) oil CB.
(B) Vacuum CB.
(C) Air blast CB.
(D) Any of these.
[accordion clicktoclose=true tag=h4][accordion-item title=”Answer ⇓” state=closed] C [/accordion-item][/accordion]
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