(19)
(11) EP 0 178 733 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
07.10.1987 Bulletin 1987/41

(43) Date of publication A2:
23.04.1986 Bulletin 1986/17

(21) Application number: 85201662

(22) Date of filing: 11.10.1985
(84) Designated Contracting States:
CH DE FR GB LI NL SE

(30) Priority: 16.10.1984 IT 2316684

(71) Applicant: SACE S.p.A. Costruzioni Elettromeccaniche
 ()

(72) Inventor:
  • Cornago, Franco
     ()

   


(54) Device for predetermining the arcing time in a direct current, low-medium voltage vacuum switch


(57) In order to increase the electrical life of a direct current, low-medium voltage vacuum switch, a device is proposed for predetermining the arcing time during switch opening. The device consists of an optical sensor, in particular of optical fibre type, able to determine the instant of contact separation, and to provide by way of a delay circuit the enabling command for discharging a capacitor bank which causes the current to pass through zero.






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