Answer / gunasekaran

insulation properties of SF6 is 2-3 time than air and it is
electro negative gas so it absorb more electron at the time
of fault and normal operating condition.in acb current
chopping is occur it is will make arc between the breaker if
you go high voltage.in vcb vacuum is good insulator than air.
so higher voltage level we r using vcb SF6 breaker

Answer / mohammed amjath

In high voltage we use SF6 or VCB.Because if we go to ACB
the arc quenching will no be proper.Where as if we use vacum
or sulphur hexafloride the arc quenching will be 100percent.

Answer / x man

DURING SWITCHING THEY PRODUCE HIGH ARC,SO BY USING VACUM
AND SF6 THE ARC CAN BE EFFECTIVELY QUENCHED.

iF ACB can be used every were they why do we need at the
other protective devices.so every thing has purpose for the
invention.

Answer / baskaran.r

in an acb the distance between terminals are fixed for 415
volts. for higher voltages this need to be much larger.
there are some makes acbs are available in 3.3 kv with
increased gap to the tune of 2 feet. For higher voltages the
gap required will be very much higher.arc handling will be
impossible in higher voltages

Answer / deepak kumar

because in acb time required to extinguish the arc is much
more as compare to sf6 & vcb,if we use acb at higher
voltage , very large amount of heat will produced during
abnormal condition( short ckt) that will damage the acb or
complete circuit

Answer / kuldeep mehla

Beacuse Dielectric strength of vacuum & SF6 gas is more as compared to ACB. Therefore, for maintaining dielectric strenght to quench the arc at the same voltage level the size of ACB will be more compared to VCB & SF6. Therefore, ACB used in low tension line mostly.

Answer / g.sridhar

According BIS,IEC standards in HT lines the Isc that current
is very highly making arc that arc is quenched by the SF6 or
vcb. If ACB has used the breaker contacts & cables are burn
out at Isc.so we used SF6 & vcb has used in HT lines for
safety purpose

Answer / grao

In high voltage we use SF6 or VCB.Because if we go to ACB
the arc quenching will no be proper.Where as if we use vacuum
or sulfur hydrochloride the arc quenching can be 100percent.

an ac induction motor gets overheated when operated at a low frequency of 25 hz a instead of 50 hz. reason?

1 Answers  

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