| 摘要 |
A switching apparatus for disconnecting and connecting power between a power source and a load employs a vacuum switch, a knife blade or air switch coupled electrically in series with the vacuum switch and a positive interlock mechanism. In the disconnect mode, at first the bias on a springloaded movable contact of the vacuum switch is relieved; then the vacuum lock that maintains the movable contact engaged with the fixed contact in the vacuum switch is overcome to cause complete separation of the contacts, thereby breaking the connection to the power source; and finally the knife blade is moved to open the air switch and to a position providing a visual indication that the power to the load has been interrupted. A continuous force is applied to the interlock mechanism, but the disconnect process occurs sequentially in three steps. During the connect mode, the three step process is reversed.
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