US Patent 8222548 Automatic transfer switch

An automatic transfer switch apparatus for use with a stand-alone generator, for supplying emergency power to a residence or small business. The automatic transfer switch apparatus is configured to sense a utility line failure, start up and stabilize the generator, and switch over the household circuits from the utility to the generator, and switch back when the utility recovers. The transfer switches incorporate motor-driven switch interlock mechanisms in several embodiments, as well as various operational features.