摘要 |
A power system is disclosed for receiving dual alternating current sources and delivering direct current to drive a load. The power system comprises four power supplies and two transfer switch modules, any of which may be removed and replaced without disabling the power system. Three of the power supplies deliver current to drive the load while the fourth is redundant. A transfer switch control circuit activates relays within the transfer switch modules, in response to a change in the voltage maintained by one or both AC sources. As long as one of the AC sources maintains a voltage within a predetermined voltage range, three of the power supplies deliver current to drive the load.
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