What is selective tripping and why is it used?

What is selective tripping and why is it used?
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1 Answer

Answer :

. It is the use of time delay ratings to cause the circuit breaker  closest to the faulty circuit to trip. This isolates the faulty circuit  without affecting other circuits.
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Related questions

. 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?

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

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. continuity of service on main bus under short circuit conditions in a branch C. isolation of short circuits by selective tripping of branch circuit breakers D. all of the above

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

Why does our GFCI breaker keep tripping?

Description : Why does our GFCI breaker keep tripping?

Last Answer : More details, please. What appliances are connected to the outlet(s) on this circuit?

Tripping on three tablespoons of nutmeg?

Description : Tripping on three tablespoons of nutmeg?

Last Answer : answer:Eating nutmeg to trip is a myth. You have to smoke it.

Any advice for road-tripping around Vancouver Island, British Columbia, Canada?

Description : Any advice for road-tripping around Vancouver Island, British Columbia, Canada?

Last Answer : answer:Write to the Parks of course; but, It would be wise to take a fast course in French with a touring book. It would make the trip fun. Here are some camping sites that might be good: ... .pc.gc.ca/voyage-travel/reserve/index_e.asp http://www.pccamping.ca/parkscanada/ http://camping-canada.com/

My (soon-to-be-replaced) air conditioner is frequently tripping the circuit breaker in my apartment. What can I do to prevent this?

Description : My (soon-to-be-replaced) air conditioner is frequently tripping the circuit breaker in my apartment. What can I do to prevent this?

Last Answer : answer:A mini-split AC unit will use less power than a regular square version and should help with the problem. However if your problem resides in old wiring with a lower amperage/threshold you might ... every time you want to use it but this has cut my electric bill dramatically. Hope this helps

What are some good/irritating tongue twisters that you know & can you say any without tripping up?

Description : What are some good/irritating tongue twisters that you know & can you say any without tripping up?

Last Answer : answer:Big black rubber baby buggy bumpers. She sells sea shells by the sea shore No, I can’t actually say them without tripping over my tongue. Fortunately, I don’t feel that my life is diminished in any way by not saying them, so I’m good!

If you have a dream about walking to school and tripping at the crosswalk An example of the latent meaning of the dream might be?

Description : If you have a dream about walking to school and tripping at the crosswalk An example of the latent meaning of the dream might be?

Last Answer : You are frightened about moving ahead in life - Apex

If you have a dream about walking to school and tripping at the crosswalk An example of the latent meaning of the dream might be?

Description : If you have a dream about walking to school and tripping at the crosswalk An example of the latent meaning of the dream might be?

Last Answer : You are frightened about moving ahead in life - Apex

An AC generator operating in parallel loses its excitation without tripping the circuit breaker. This will __________. A. not affect the faulty generator due to the compensation of the other generators B. cause the slip rings to melt C. cause a low voltage differential to develop between the armature and the bus D. cause high currents to be induced in the field windings

Description : An AC generator operating in parallel loses its excitation without tripping the circuit breaker. This will __________. A. not affect the faulty generator due to the compensation of the other generators B. ... between the armature and the bus D. cause high currents to be induced in the field windings

Last Answer : Answer: D

Component F in the illustrated device is for _________. EL-0033 A. short circut protection B. latching the trip unit closed after resetting the breaker C. overload protection D. providing a flexible connection between the input terminal G and the tripping unit E

Description : Component F in the illustrated device is for _________. EL-0033 A. short circut protection B. latching the trip unit closed after resetting the breaker C. overload protection D. providing a flexible connection between the input terminal G and the tripping unit E

Last Answer : Answer: C

A reverse-current relay will prevent AC generator motorization by ____________. A. automatically redirecting the load B. automatically speeding up the prime mover C. tripping the panel board main switch D. tripping the generator circuit breaker

Description : A reverse-current relay will prevent AC generator motorization by ____________. A. automatically redirecting the load B. automatically speeding up the prime mover C. tripping the panel board main switch D. tripping the generator circuit breaker

Last Answer : Answer: D

The timer element of a reverse power relay cannot be energized unless _____________. A. the power flow is the same as the tripping direction B. the power flow is the opposite to the tripping direction C. the movement of the disk is damped by a permanent magnet D. one generator is motorized

Description : The timer element of a reverse power relay cannot be energized unless _____________. A. the power flow is the same as the tripping direction B. the power flow is the opposite to the tripping direction C. the movement of the disk is damped by a permanent magnet D. one generator is motorized

Last Answer : Answer: A

In addition to testing the calibration of a circuit breaker, maintenance should include all of the following EXCEPT ______________. A. changing out of magnetic elements and thermal heaters yearly B. checking for corrosion, accumulation of dirt and thermal fatigue C. inspecting for loose or missing parts D. making sure foreign matter does not block tripping element

Description : In addition to testing the calibration of a circuit breaker, maintenance should include all of the following EXCEPT ______________. A. changing out of magnetic elements and thermal heaters yearly B. ... for loose or missing parts D. making sure foreign matter does not block tripping element

Last Answer : Answer: A

The arc resulting from the tripping of a circuit breaker is prevented from damaging the contacts by _____________. A. designing the contacts to open slowly B. directing the arc into an arc chute C. an inverse timed thermal trip for short circuit currents D. instantaneous magnetic trip for overload currents

Description : The arc resulting from the tripping of a circuit breaker is prevented from damaging the contacts by _____________. A. designing the contacts to open slowly B. directing the arc into an ... an inverse timed thermal trip for short circuit currents D. instantaneous magnetic trip for overload currents

Last Answer : Answer: B

The timer element of a reverse power relay cannot be energized unless _____________. A. one generator is fully motorized B. the movement of the disk is damped by a permanent magnet C. the power flow is the same as the tripping direction D. the power flow is the opposite to the tripping direction

Description : The timer element of a reverse power relay cannot be energized unless _____________. A. one generator is fully motorized B. the movement of the disk is damped by a permanent magnet C. the power flow is the same as the tripping direction D. the power flow is the opposite to the tripping direction

Last Answer : Answer: C

Why breaker tripping is prohibited on very low pressure?

Description : Why breaker tripping is prohibited on very low pressure?  

Last Answer : The efficiency with which the arc quenching is taking place in the breaker depends on the air pressure. So if the air pressure is low effective arc quenching will not take place which will result in damage of CB. Hence the tripping of the breaker at very low air pressure is prevented.  

Why under voltage tripping of motor is incorporated in motor feeder breakers?

Description : Why under voltage tripping of motor is incorporated in motor feeder breakers? 

Last Answer : The under voltage can occur in case of bus fault. If the motors are kept connected they will feed the fault which may cause the damage. Due to the back feeding from the motor the motor will slow down ... case pht motor will not rotate for the designed 3 minute period in case of bus under voltage).  

What is the safe maximum tripping speed of a turbine operating at 2500 rpm?

Description : What is the safe maximum tripping speed of a turbine operating at 2500 rpm?

Last Answer : The rule is to trip at 10 percent overspeed. Therefore, 2500 x 1.10 = 2750 rpm.

For a traction transformer circuit breaker state: 1) Rated current and rupturing capacity 2) Any two tests it should be capable of withstanding 3) Overall tripping time and relay time.

Description : For a traction transformer circuit breaker state: 1) Rated current and rupturing capacity 2) Any two tests it should be capable of withstanding 3) Overall tripping time and relay time.

Last Answer : Ans: 1) Rated current --- 750 A and Rupturing capacity --- 500 MVA  2) Any two tests it should be capable of withstanding --- Breaking test , Reclosing test , Endurance test ( any two )  3) Overall tripping time --- 0.14 sec and Relay time --- 0.04 sec