The following is/are the characteristics of SF6 circuit breakers: (A) It does not need an auxiliary breaking chamber (B) Short break time of 2 to 2.5 cycles (C) All of the above (D) None of the above
Last Answer : The following is/are the characteristics of SF6 circuit breakers: (A) It does not need an auxiliary breaking chamber (B) Short break time of 2 to 2.5 cycles (C) All of the above (D) None of the above
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asked
May 8, 2018
by
anonymous

The arc temperature in Oil Circuit Breaker may reach up to_______. (A) 5,000° K (B) 8,000° K (C) 10,000° K (D) None of the above
Last Answer : The arc temperature in Oil Circuit Breaker may reach up to 5,000° K
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117 views
1 answer
asked
May 8, 2018
by
anonymous

The number of cycles in which a high speed circuit breaker can complete its operation is (A) 3 to 8 (B) 10 to 18 (C) 20 to 30 (D) 40 to 50
Last Answer : The number of cycles in which a high speed circuit breaker can complete its operation is 3 to 8
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642 views
1 answer
asked
May 8, 2018
by
anonymous

A circuit breaker is designed to protect an electrical circuit from damage caused by : (A) Over load (B) Short circuit (C) Over current (D) All of the above
Last Answer : A circuit breaker is designed to protect an electrical circuit from damage caused by : (A) Over load (B) Short circuit (C) Over current (D) All of the above
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106 views
1 answer
asked
May 8, 2018
by
anonymous

The Minimum Oil Circuit Breaker (MOCB) is named because of : (A) Reduced requirement of oil (B) Reduced requirement of air (C) All of the above (D) None of the above
Last Answer : The Minimum Oil Circuit Breaker (MOCB) is named because of : Reduced requirement of oil
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164 views
1 answer
asked
May 8, 2018
by
anonymous

For selecting a circuit breaker, ______ should be determined. (A) initial current that flows on occurrence of a short circuit only (B) transient current that flows at the time of circuit interruption only (C) resonant frequency only (D) (A) and (B)
Last Answer : For selecting a circuit breaker, ______ should be determined. (A) initial current that flows on occurrence of a short circuit only (B) transient current that flows at the time of circuit interruption only (C) resonant frequency only (D) (A) and (B)
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78 views
1 answer
asked
Apr 30, 2018
by
anonymous

ln a minimum oil circuit breaker the oil is used
Last Answer : ln a minimum oil circuit breaker the oil is used to act as circuit breaking medium only
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84 views
1 answer
asked
Apr 26, 2018
by
anonymous
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Last Answer : Arc in a circuit breaker is interrupted at zero current.
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1 answer
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Mar 20, 2018
by
anonymous
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Last Answer : The arc voltage produced in A.C. circuit breaker is always in phase with the arc current.
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319 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : In a circuit breaker the basic problem is to transmit large power.
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121 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : Ionization in circuit breaker is facilitated by high temperature, increase of mean free path, increasing field strength.
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304 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The voltage appearing across the contacts after opening of the circuit breaker is called recovery voltage.
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425 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : Air blast circuit breaker is used for repeated duty.
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78 views
1 answer
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Mar 19, 2018
by
anonymous

Last Answer : Magnetic circuit breaker has instantaneous trip action.
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218 views
1 answer
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Mar 19, 2018
by
anonymous

Last Answer : Thermal circuit breaker has delayed trip action.
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154 views
1 answer
asked
Mar 19, 2018
by
anonymous

Last Answer : The arcing contacts in a circuit breaker are made of copper tungsten alloy.
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117 views
1 answer
asked
Mar 19, 2018
by
anonymous

Last Answer : SF6 gas is nontoxic.
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79 views
1 answer
asked
Mar 19, 2018
by
anonymous

Explain about Circuit Breaker
Last Answer : Ans: CIRCUIT BREAKERS: In the case of outdoor type installation, the circuit breakers have fixed location and the station layout is such that adequate section clearances are always available from ... carried out as above, every circuit breaker will be completely overhauled after five year interval.
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1 answer

How to Reset a Circuit Breaker
Last Answer : How to Reset a Circuit Breaker All is well with the lights and your electrical appliances one minute, then everything falls into pitch-black darkness the next moment. When a room in your house ... electrical fires. With these tips, a power surge does not have to be a permanent inconvenience.
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11 views
1 answer
asked
May 15, 2021
by
anonymous

How to Install a Circuit Breaker
Last Answer : How to Install a Circuit Breaker A circuit breaker is an essential component of a home's electric system. When power surges occur, it trips then shuts off the electricity, preventing ... -functional electrical system. Just make sure you take proper safety precautions when installing this device.
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14 views
1 answer
asked
May 14, 2021
by
anonymous

Explain working of static AC circuit breaker.
Last Answer : Static AC Circuit breaker: The circuit configuration of static AC circuit breaker using SCR is shown in the figure. When switch S' is closed, the SCRs T1 and T2 are fired in positive ... non-availability of gate current. Thus the maximum time delay for breaking the circuit is one half-cycle.
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213 views
1 answer
asked
May 21, 2020
by
anonymous
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Explain working of AC circuit breaker using SCR with circuit diagram.
Last Answer : AC Circuit Breaker: The circuit configuration of static AC circuit breaker using SCR is shown in the figure. When switch S' is closed, the SCRs T1 and T2 are fired in positive ... to non-availability of gate current. Thus the maximum time delay for breaking the circuit is one half-cycle.
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938 views
1 answer
asked
Oct 13, 2019
by
anonymous

State function of starter and ELCB. (Earth Leakage Circuit Breaker)
Last Answer : i) Function of Starter:- 1. To prevent the high starting current OR to minimize the starting current. 2. To give supply failure protection 3. To give over load and short circuit protection ... an installation and cut off the circuit from power supply and avoid electrical shock to the person.
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459 views
1 answer
asked
Sep 18, 2018
by
anonymous

Breaking capacity of a circuit breaker is usually expressed in terms of (1) Ampere (2) Volts (3) MW (4) MVA
Last Answer : Breaking capacity of a circuit breaker is usually expressed in terms of MVA
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271 views
1 answer
asked
Apr 30, 2018
by
anonymous

The arc voltage in a circuit breaker is :
Last Answer : The arc voltage in a circuit breaker is : in phase with the arc current
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135 views
1 answer
asked
Apr 29, 2018
by
anonymous

Which of the following is used in a circuit breaker as the medium in which the arc forms? A) Insulating gas B) Insulating oil C) Vacuum D) All the above
Last Answer : Which of the following is used in a circuit breaker as the medium in which the arc forms? A) Insulating gas B) Insulating oil C) Vacuum D) All the above
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120 views
1 answer
asked
Apr 29, 2018
by
anonymous

Describe the construction of SF6 circuit breaker with neat diagram.
Last Answer : Construction of SF6 Circuit Breaker : A sulphur hexafluoride (SF6) circuit breaker consists of fixed and moving contacts enclosed in a chamber. The chamber is called arc interruption ... contact, moving contact and arcing horn are coated with a copper-tungsten arc-resistant material.
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142 views
1 answer
asked
Jun 23, 2020
by
anonymous

Explain construction and working of SF6 circuit breaker.
Last Answer : Construction: A sulphur hexafluoride (SF6) circuit breaker consists of fixed and moving contacts enclosed in a chamber. The chamber is called arc interruption chamber, which contains the ... arc being extinguished. Finally the gas enters the contact space increasing the dielectric strength.
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397 views
1 answer
asked
Jul 21, 2019
by
anonymous

If the % reactance upto the fault point is 20%, then the short circuit current will be
Last Answer : If the % reactance upto the fault point is 20%, then the short circuit current will be 5 times the full load current
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3.0k views
1 answer
asked
May 8, 2018
by
anonymous

Which of the following circuit breakers has high reliability & minimum maintenance? (A) Bulk oil type CB (B) Air blast CB (C) Vacuum CB (D) Sulphur hexafluoride CB
Last Answer : Which of the following circuit breakers has high reliability & minimum maintenance? (A) Bulk oil type CB (B) Air blast CB (C) Vacuum CB (D) Sulphur hexafluoride CB
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302 views
1 answer
asked
May 8, 2018
by
anonymous

Last Answer : A fuse in a motor circuit provides protection against short-circuit and overload.
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160 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : Air blast circuit breakers for 400 kV power system are designed to operate in 50 millisecond.
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210 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The short circuit in any winding of the transformer is the result of impulse voltage.
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174 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The time of closing the cycle, in modern circuit breakers is 0.003 sec.
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123 views
1 answer
asked
Mar 20, 2018
by
anonymous

The current zero interruption, in oil and air blast circuit breakers, is achieved by?
Last Answer : The current zero interruption, in oil and air blast circuit breakers, is achieved by lengthening of the gap, cooling and blast effect.
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439 views
1 answer
asked
Mar 19, 2018
by
anonymous

Last Answer : Circuit breakers are essentially current carrying contacts called electrodes.
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328 views
1 answer
asked
Mar 19, 2018
by
anonymous

Last Answer : Circuit breakers usually operate under transient state of short-circuit current.
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107 views
1 answer
asked
Mar 19, 2018
by
anonymous

Arc in a circuit behaves as?
Last Answer : Arc in a circuit behaves as a resistance decreasing with voltage rise across the arc.
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285 views
1 answer
asked
Mar 19, 2018
by
anonymous

In which fault the maximum short circuit current occurs?
Last Answer : In three phase bolted fault the maximum short circuit occurs.
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131 views
1 answer
asked
Mar 19, 2018
by
anonymous
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What Is Sf6 Circuit Breaker?
Last Answer : SF6 is Sulpher hexa Flouride gas.. if this gas is used as arc quenching medium in a Circuitbreaker me SF6 CB.
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1 answer
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For interrupting capacitive currents which Circuit Breaker (CB) is used a) SF6 CB b) Oil CB c) Vacuum CB d) Air blast CB
Last Answer : Ans: Vacuum CB
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17 views
1 answer

Which of the following circuit breakers has high reliability and minimum maintenance ? (a) Air blast circuit breakers (b) Circuit breaker with SF6 gas (c) Vacuum circuit breakers (d) Oil circuit breakers
Last Answer : (b) Circuit breaker with SF6 gas
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10 views
1 answer

Which of the following medium is employed for extinction of arc in air circuit breaker ? (a) Water (b) Oil (c) Air (d) SF6
Last Answer : (c) Air
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52 views
1 answer

What are the levels of SF6 gas in 220 kV breaker and their significance?
Last Answer : 7 kg/cm2 - normal pressure 5.2 bar - alarm 5.0 bar - closing/tripping operation blocked.
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3 views
1 answer

What is the purpose of compressed air in SF6 breaker?
Last Answer : This used for drive for opening and closing of the contacts. (Arc quenching is taken care by SF6 gas)
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1 answer

Can An Rc Circuit Be Used As Clock Source For 8085?
Last Answer : Answer :Yes, it can be used, if an accurate clock frequency is not required. Also, the component cost is low compared to LC or Crystal.
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57 views
1 answer

What is the purpose of Overload Protection in a motor circuit?
Last Answer : Ans. The Overload Protection is used in a motor circuit to protect it from sustained over currents.
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56 views
1 answer

microproject on synchronised UJT triggring circuit
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How to Do Circuit Training
Last Answer : How to Do Circuit Training Circuit exercise is a set of exercises designed to burn as much calories as possible while integrating and engaging different kinds of movements all over your body. After finishing ... up your stamina to be able to finish five circuits in a session, so pace yourself.
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1 answer

Refer to the circuit below. The total absorbed (consumed) power is:
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