Power switching system

摘要

A power controller has upstream and downstream switches in series connection to provide redundant switching for power supplied from a power source to a load. A switch operating system closes the switch closer to the load first (downstream) and then the switch closer to the source (upstream). The operating system conditions closing the downstream switch on absence of power voltage on an upstream power terminal of the downstream switch. A preferred embodiment of the operating system performs a number of real time status checks during the connection process to assure that power voltage is properly absent and present at switch terminals during the stages of the connection process. This operating system guards against supplying power to the load if either the upstream or downstream switch's pair of contacts are welded at the time the connection process starts.