How do circuit breakers keep the wires in an electric circuit from overheating?

1 Answer

Answer :

They reduce the flow of electrons.

Related questions

Description : How do circuit breakers keep the wires in an electric circuit from overheating?

Last Answer : They reduce the flow of electrons.

Description : When wires are connected to the terminals of the battery what causes electric current in the circuit?

Last Answer : The energy stored in the chemicals of the battery

Description : Electric propulsion coupling excitation is reduced at slow speeds to ___________. A. increase speed control B. increase shaft torque C. prevent coupling overheating D. prevent coupling slippage

Last Answer : Answer: C

Description : Multiple grounds have developed and were initialy indicated by the grounddetecting system as one ground. The FIRST step in locating the grounds is to _____________. A. examine the main bus bars ... no longer indicates any grounds C. change over generators D. check each circuit with a megohmmeter

Last Answer : Answer: B

Description : A circuit is protected from overheating by a/an ___________. A. pyrometer B. thermal overload relay C. magnetic contactor D. overload transformer

Last Answer : Answer: B

Description : Electrical circuits are protected against overheating by means of a/an ______________. A. circuit breaker B. amplifier C. diode D. capacitor

Last Answer : Answer: A

Description : Overheating of relay contacts or contact born out is due to (a) slow making and breaking of load circuit contacts (b) foreign matter on the contact surface (c) too low contact pressure (d) all of the above

Last Answer : (d) all of the above

Description : An LED is operated on a 12 volt automobile circuit. The voltage drop across the LED is 2 volts and the current must be limited to 50 milliamps to prevent its overheating and destruction. What size resistor must be used? w) 60 ohms x) 100 ohms y) 120 ohms z) 200 ohms

Last Answer : ANSWER: Z -- 200 OHMS

Description : How can I keep my my motherboard from overheating?

Last Answer : Get a well ventilated case in a cool area with fans. Make sure heat sinks and fans are properly installed.

Description : What is the best way to keep a laptop from overheating?

Last Answer : Make sure your laptop is free from dust and that your fans are working properly. Put fan on your laptop.or use it in air condition.Do not put laptop on the bed and use it. Dust your laptop ... object like halve an inch under the notebook infront.The reason is to allow ample air to blow under it.

Description : When I run more electrical appliances, the circuit breakers go out and I have to go "throw them". How to fix it? Call us electricians to put stronger circuit breakers? Or how is it handled?

Last Answer : calculate the power consumption of the appliances (current must be lower than the value of the circuit breaker (s)) the question is what appliances are involved (some, typically motors, need more ... "electricity", invite electricians and have specific options and needs explained "on the spot". ;-)

Description : When there's a storm outside and it hits the lead, will it help me that I have circuit breakers at home? Or what will burn in the drawer so?

Last Answer : the circuit breaker will not help, even the switched-off switch in the socket will not help, it may not burn out, but the electronics may be destroyed - even invisibly from the outside -

Description : Where are all the controls on most circuit breakers?

Last Answer : The only control on a circuit breaker is its on/off/reset leveror button.

Description : Are circuit breakers more expensive the better they are?

Last Answer : On one hand you don't want to search for the absolute cheapest circuit breaker you can find.On the other this is a competitive business and most circuit breakers have similar quality and price ranges

Description : Accidental grounds in a shipboard electrical system must be repaired as soon as possible as they will ____________. A. result in immediate power outages B. damage circuit breakers C. appear on the ground detection system D. damage insulation and may cause outages

Last Answer : Answer: D

Description : A ground is indicated by the ground-detecting system on the main electrical switchboard. The FIRST step in locating the actual ground is to _____________. A. close all circuit breakers in ... ground detection system indicates normal C. change over generators D. check each circuit with a megohmmeter

Last Answer : Answer: B

Description : During maintenance of circuit breakers, _______________. A. always smooth roughened contact surfaces with a file B. never pass more than rated breaker current through the overload heater element C. ... wear and misalignment of main contacts D. assume heater elements installed are of correct size

Last Answer : Answer: C

Description : Undervoltage trips are frequently installed on switchboard circuit breakers to trip ____________. A. out generators in the event of severe arcing or sparking B. out generators when there is reversal of power ... , but continues to run D. out generators when there is low voltage in the main circuit

Last Answer : Answer: D

Description : Periodic testing of circuit breakers is necessary to assure that a correctly rated and properly installed unit _________________. A. can trip faster as it increases in age B. will continue to provide ... not exceed its interrupting capacity D. be able to withstand at least 125% of applied voltage

Last Answer : Answer: B

Description : You can determine if a circuit breaker has tripped by ________________. A. examining the position of the handle B. checking for which of the breakers is warm C. looking for a burned-out link D. all of the above

Last Answer : Answer: A

Description : The purpose of a main switchboard circuit breaker's reverse-power trip is to _____________. A. prevent main circuit overload B. protect the circuit breaker blowout coil C. prevent alternator motorization D. prevent low voltage tripout

Last Answer : Answer: C

Description : A 'dead front' switchboard is one _____________. A. without switches on it B. with insulated switches and no exposed terminals C. without circuit breakers D. without safety hand rails nor rubber mats

Last Answer : Answer: B

Description : Protection against sustained overloads occurring in molded-case circuit breakers is provided by a/an __________. A. overvoltage release B. thermal acting trip C. thermal overload relay D. current overload relay

Last Answer : Answer: B

Description : The purpose of a short circuit forcing module (short time trip) installed in a branch line is to provide ____________. A. high speed clearance of low impedance short circuits in the branch B. ... C. isolation of short circuits by selective tripping of branch circuit breakers D. all of the above

Last Answer : Answer: D

Description : What are different types of circuit breakers employed in thermal power plant?

Last Answer : Answer: For low voltage operation 415/220V vacuum circuit breakers or air break circuit breakers are employed. For voltage ratings about 6.6kV and beyond SF6 circuit breakers are employed.

Description : What are different types of circuit breakers employed in thermal power plant?

Last Answer : For low voltage operation 415/220V vacuum circuit breakers or air break circuit breakers are employed. For voltage ratings about 6.6kV and beyond SF6 circuit breakers are employed.

Description : Why Isolation switches are provided along with the circuit breakers?

Last Answer : Isolation switches are provided for separating the disconnected element from the live portion of the system for the purpose of safety

Description : Air Blast Circuit Breakers Advantages Disadvantages

Last Answer : Air Blast Circuit Breakers Advantages Disadvantages In air blast circuit breakers, compressed air at a pressure of 20-30 kg/cm2 is employed as an arc quenching medium. Air blast circuit breakers ... air blast circuit breaker current chopping problem exists There is a problem of re-striking voltage

Description : Why we need isolation transformers in power circuit ? why cant we use breakers to isolate?

Last Answer : In Isolation transformer is used, if there is change in parameter values of any side, the other side parameters will remain unchanged.

Description : How direct tests are conducted in circuit breakers?

Last Answer : Using a short circuit generator as the source. Using the power utility system or network as the source.

Description : State the different types of circuit breakers.

Last Answer : Air ,oil,vacuum circuit breakers.

Description : Write the classifications of test conducted on circuit breakers.

Last Answer : Type test Routine test Reliability test Commissioning test

Description : Write the classification of circuit breakers based on the medium used for arc extinction?

Last Answer : Air break circuit breaker Oil circuit breaker Minimum oil circuit breaker Air blast circuit breaker SF6 circuit breaker Vacuum circuit breaker

Description : In which of the following item(s), spring is used to store energy. (A) clocks (B) toys (C) circuit breakers (D) all of the above

Last Answer : (D) all of the above

Description : What are the protections provided in PMCC circuit breakers?

Last Answer : 1. IDMT O/C (CDG 34). 2. IDMT E/F (CDG 11).  3. Under voltage (40% of 110V). 

Description : Air blast circuit breakers for 400 kV power system are designed to operate in (a) 100 microsecond (b) 50 millisecond (c) 0.5 sec (d) 0.1 sec

Last Answer : (b) 50 millisecond

Description : 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

Description : Insulation resistance of high voltage circuit breakers is more than (a) 1 mega ohms (b) 10 mega ohms (c) 100 mega ohms (d) 500 mega ohms

Last Answer : (c) 100 mega ohms

Description : The time of closing the cycle, in modern circuit breakers is (a) 0.003 sec (b) 0.001 sec (c) 0.01 sec (d) 0.10 sec (e) none of the above

Last Answer : (a) 0.003 sec

Description : The current zero interruption, in oil and air blast circuit breakers, is achieved by (a) lengthening of the gap (b) cooling and blast effect (c) both (a) and (b) (d) deionizing the oil with forced air (e) none of the above

Last Answer : (c) both (a) and (b)

Description : Circuit breakers are essentially (a) current carrying contacts called electrodes (b) arc extinguishers (c) circuits to break the system (d) transformers to isolate the two systems (e) any of the above

Last Answer : (a) current carrying contacts called electrodes

Description : Circuit breakers usually operate under (a) transient state of short-circuit current (b) sub-transient state of short-circuit current (c) steady state of short-circuit current (d) after D.C. component has ceased

Last Answer : (a) transient state of short-circuit current

Description : Fault diverters are basically (a) fuses (b) relays (c) fast switches (d) circuit breakers

Last Answer : (c) fast switches

Description : On which of the following routine tests are conducted ? (a) Oil circuit breakers (b) Air blast circuit breakers (c) Minimum oil circuit breakers (d) All of the above

Last Answer : (d) All of the above

Description : . If the power distribution system shown in figure 2-22 uses selective tripping, what is the time delay rating for each of the circuit breakers shown?

Last Answer : CB1-long time delay; CB2, CB3-short time delay; CB4 through

Description : What are the three time delay ratings for circuit breakers?

Last Answer : Instantaneous, short time delay, and long time delay.

Description : The Use of high speed circuit breakers  A) Reduces the short circuit current B) Improves system stability C) Decreases system stability D) Increases the short circuit current

Last Answer : Q

Description : 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