| 摘要 |
<p>An improved pneumatic power unit is provided including a penumatic piston reciprocally operable within an operating cylinder housing, which, in one conceivable application, operates the contact structure of a power circuit-breaker, and uses a normally-open three-way valve, which normally provides high-pressure gas on both sides of the driving piston within the operating cylinder housing. During the closing operation of the circuit-breaker, when the pneumatic power unit of the instant invention is applied to this particular application, the three-way normally-open valve is operated to exhaust one side of the driving piston, and the high-pressure gas already present on the other side of the piston provides the required closing force to close the contacts of the circuit-breaker against the usually-provided accelerating spring pressure tending to open the breaker.</p> |
