Description and operation
Pole operation
(Interrupting principle)
L13--003EN/02
4/6
08--2000
E ALSTOM
Opening, continued
Operation, continued
The table below gives the continuation of opening stages :
Stage Description
“OPEN” position
The arc has been extinguished.
The SF
6
molecules, separated by the arc, are re--
formed instantaneously.
Residual gases left over from the interruption opera-
tion are absorbed by the molecular sieve, situated at
the base of the pole. A few powdery compounds are
deposited in the form of dust which is quite harmless
for the circuit breaker.
Special case
of small currents
For small currents (example : operating no--load lines, transformers or ca-
pacitor banks), the thermal energy of the arc is too low to provide enough ex-
cess pressure.
Consequently, the conventional autopneumatic effect developing in the vol-
ume (Vp) is used mainly, to blast the arc.
Vp
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