| 摘要 |
<p>The pressure medium drive is provided for opening and closing the contacts (e1, e2) of an electric circuit-breaker. It contains a pressure medium reservoir (r), a drive piston (t) which slides in a drive cylinder (c) and acts on a mechanism (j) for displacing a movable contact (e1) of the circuit-breaker, and a reversing valve (s) for the selective connection of the pressure medium reservoir (r) to the drive cylinder (c) or of the drive cylinder (c) to an outlet volume for the pressure medium. This pressure medium drive is of simple, inexpensive construction and can open the contacts of the circuit-breaker considerably faster than it can close them. This is due to an interposed valve (v) which is disposed between the pressure medium reservoir (r) and the reversing valve (s) and has a flow cross section determined by the closing time of the contacts (e1, e2), and to the much larger flow cross section of the reversing valve (s). This interposed valve (v) is open when closing the contacts (e1, e2) and passes pressure medium from the pressure medium reservoir (r) via the reversing valve (s) into the drive cylinder (c). After closing of the contacts (e1, e2), it is closed and then establishes the connection between the drive cylinder (c) and the outlet volume by reversing the reversing valve (s).</p> |
