Electric control system with rotary mechanical interlock and timing mechanism

An electric control system for switching between two current supply lines extending to a load, comprising an isolation switching structure, a transfer switching structure, and a bypass switching structure;

• the isolation switching structure including first and second control devices, the transfer switching structure including third and fourth control devices, the bypass switching structure including fifth, sixth, and seventh control devices, all of the control devices being operable between open and closed circuit conditions;
• one of the current supply lines including a first of two parallel paths extending to the load with one path including the first, third, and sixth control devices in series and with the other path including the fifth control device;
• the other of the current supply lines including a second of two parallel paths extending to the load with one path including the second, fourth, and sixth control devices in series and with the other path including the seventh control device, the bypass switching structure including interlock timing means between the fifth, sixth, and seventh control devices for preventing simultaneous closing of one control device when another of the control devices is closed.