"Air" and "Vacuum" describe how the breaker extinguishes the arcing current. An Air breaker opens far enough that the dielectric strenght of air is enough to extinguish the arc. A vacuum breaker's contacts are in a vacuum. Oil breakers use oil. SF6 breakers use SF6 gas to extinguish the arc.
yes SF6 gas is used in modern ckt. breaker.
Rather than where? Circuit breakers are always located in substations.
SF6 is used to increase the dielectric strength of the gap in the circuit breaker. If the gas pressure is too low, the dielectric strength will be inadequate to break the voltage applied across the breaker contacts. This means electricity will continue to arc across the contacts when opened, causing the breaker to heat up and likely fail catastrophically (explode). Most gas breakers have low gas alarms and trip contacts. If there is no way to bypass the breaker, a low gas trip contact can be used to open the breaker before the gas pressure gets too low to allow openning.
Craig, Please refer to Australian Standard AS3000:2007 for the answer.
vcb is have vaccume and sf6 cb is filled with sf6 gas which will have good arc quencing property
A vacuum circuit breaker has the circuit interrupting contacts inside a vacuum bottle. Without air the arc created by interrupting the circuit contains only material from the contacts. As a result the arc cannot sustain itself as well as it would if in air and the contacts will be able to handle higher currents. In an SF6 breaker the arc occurs in SF6 gas. SF6 captures free electrons from the arc quickly quenching it. In the process SF6 is broken apart but will recombine back into SF6. Some "SF6" breakers use vacuum bottles. This results in the small size of SF6 Switchgear with the advantages of vacuum breakers.
SF6 circuit breaker
As the breaker is tripped, a magnetic coil is beneath it and as the movable contact falls into the coil the arc is elongated in a spiral caused by the magnetic coil until the SF6 quenches the arc.
Less than 65 ohms
"Air" and "Vacuum" describe how the breaker extinguishes the arcing current. An Air breaker opens far enough that the dielectric strenght of air is enough to extinguish the arc. A vacuum breaker's contacts are in a vacuum. Oil breakers use oil. SF6 breakers use SF6 gas to extinguish the arc.
yes SF6 gas is used in modern ckt. breaker.
Rather than where? Circuit breakers are always located in substations.
Yes.
SF6 is colorless
SF6 is used to increase the dielectric strength of the gap in the circuit breaker. If the gas pressure is too low, the dielectric strength will be inadequate to break the voltage applied across the breaker contacts. This means electricity will continue to arc across the contacts when opened, causing the breaker to heat up and likely fail catastrophically (explode). Most gas breakers have low gas alarms and trip contacts. If there is no way to bypass the breaker, a low gas trip contact can be used to open the breaker before the gas pressure gets too low to allow openning.
Craig, Please refer to Australian Standard AS3000:2007 for the answer.