Last Answer : Air blast circuit breakers for 400 kV power system are designed to operate in 50 millisecond.
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209 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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438 views
1 answer
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Mar 19, 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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83 views
1 answer
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Apr 26, 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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637 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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163 views
1 answer
asked
May 8, 2018
by
anonymous
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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

Last Answer : Arc in a circuit breaker is interrupted at zero current.
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84 views
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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317 views
1 answer
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Mar 20, 2018
by
anonymous
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Last Answer : In a circuit breaker the basic problem is to transmit large power.
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121 views
1 answer
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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
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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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419 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : Magnetic circuit breaker has instantaneous trip action.
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217 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
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Mar 19, 2018
by
anonymous

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

what is SF6 circuit breaker?
Last Answer : SF6 is Sulpher hexa Fluoride gas. If this gas is used as arc quenching medium in a Circuit breaker means SF6 CB.
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95 views
2 answers
asked
Dec 4, 2017
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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24 views
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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10 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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212 views
1 answer
asked
May 21, 2020
by
anonymous

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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937 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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457 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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268 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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134 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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117 views
1 answer
asked
Apr 29, 2018
by
anonymous

Which circuit is used as amplitude comparator?
Last Answer : Schmitt trigger circuit is used as amplitude comparator.
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371 views
1 answer
asked
May 3, 2018
by
anonymous

A dummy strain gage is used in a quarter bridge strain gage circuit to : (A) compensate for changes in temperature and lead wire resistance (B) produce more output voltage from the bridge (C) increase the sensitivity of the bridge (D) compensate lead wire resistance only
Last Answer : A dummy strain gage is used in a quarter bridge strain gage circuit to : compensate for changes in temperature and lead wire resistance
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114 views
1 answer
asked
Apr 29, 2018
by
anonymous

An unshielded moving iron voltmeter is used to measure the voltage in an AC circuit. The stray DC magnetic field having a component along the axis will be (1) unaffected (2) decreased (3) increased (4) either decreased or increased depending on the direction of the DC field
Last Answer : An unshielded moving iron voltmeter is used to measure the voltage in an AC circuit. The stray DC magnetic field having a component along the axis will be either decreased or increased depending on the direction of the DC field
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334 views
1 answer
asked
Apr 29, 2018
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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300 views
1 answer
asked
May 8, 2018
by
anonymous

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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109 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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157 views
1 answer
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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

Last Answer : Circuit breakers are essentially current carrying contacts called electrodes.
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327 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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105 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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284 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

Light triggering is mainly used in
Last Answer : Light triggering is mainly used in High voltage direct current transmission
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441 views
1 answer
asked
May 8, 2018
by
anonymous
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A relay used for protection of motors against overload is : (A) Impedance relay (B) Electromagnetic attraction type (C) Thermal relay (D) Buchholz's relay
Last Answer : D
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548 views
2 answers
asked
May 8, 2018
by
anonymous

Earthing switch is used for? (A) Measuring of safety voltage (B) Protection of equipment from ground faults (C) Discharging residual energies (D) All of the above
Last Answer : Earthing switch is used for? (A) Measuring of safety voltage (B) Protection of equipment from ground faults (C) Discharging residual energies (D) All of the above
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113 views
1 answer
asked
May 8, 2018
by
anonymous
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Auto reclosing is used in case of
Last Answer : Auto reclosing is used in case of air blast C.B.
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95 views
1 answer
asked
May 3, 2018
by
anonymous
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A negative sequence relay is used for protection of (1) Generator (3) Motor (2) Transformer (4) Long Transmission lines
Last Answer : A negative sequence relay is used for protection of Generator
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627 views
1 answer
asked
May 1, 2018
by
anonymous

The material used in liquid fuses is (1) SF6 (3) carbon tetra chloride (2) distilled water (4) transformer oil
Last Answer : The material used in liquid fuses is carbon tetra chloride
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394 views
1 answer
asked
Apr 30, 2018
by
anonymous

IDMT relays are used to protect the transformer against : (A) Internal short -circuits (B) Open circuits (C) External short circuits (D) Oil leakage
Last Answer : IDMT relays are used to protect the transformer against : External short circuits
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3.1k views
1 answer
asked
Apr 30, 2018
by
anonymous

Series reactors are used to
Last Answer : Series reactors are used to bring down the fault level within the capacity of the switchgear
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77 views
1 answer
asked
Apr 26, 2018
by
anonymous

Regulating-transformers are used in power systems for control of
Last Answer : Regulating-transformers are used in power systems for control of power flow
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149 views
1 answer
asked
Apr 26, 2018
by
anonymous
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Surge absorbers are used for protection against
Last Answer : Surge absorbers are used for protection against low voltage high frequency oscillations
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3.0k views
1 answer
asked
Apr 26, 2018
by
anonymous

Last Answer : A switchgear is device used for switching, controlling and protecting the electrical circuit and equipment.
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258 views
1 answer
asked
Mar 20, 2018
by
anonymous
