| (19) |
 |
|
(11) |
EP 0 248 342 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
23.11.1988 Bulletin 1988/47 |
| (43) |
Date of publication A2: |
|
09.12.1987 Bulletin 1987/50 |
| (22) |
Date of filing: 26.05.1987 |
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| (84) |
Designated Contracting States: |
|
AT CH DE ES FR GB IT LI |
| (30) |
Priority: |
31.05.1986 GB 8613263
|
| (71) |
Applicant: CRABTREE ELECTRICAL INDUSTRIES LIMITED |
|
() |
|
|
| |
|
| (54) |
Circuit breakers, and a method of increasing the breaking capacity of a circuit breaker |
(57) A miniature circuit breaker of the kind comprising two arc runners (20, 22) which
diverge towards an arc stack (24), onto which an arc is transferred as contacts of
the circuit breaker are opened.
A supplementary runner (30) is provided, onto which the arc is transferred from the
first of said runners (20), so that the arc extends between the second (22) and the
supplementary runner (30). The supplementary runner (30) is connected into the circuit
through a high impedence, so that the rate of increase of arcing current is reduced
as the arc travels into the arc stack.