The Micro-AT Source-Transfer Control is utilized in S&C Source-Transfer Pad-Mounted Gear in conjunction with Mini-Rupter Switches driven by stored-energy operators, to provide for automatic source transfer of common-bus primary-selective systems.

This control continuously monitors the condition of both power sources and initiates automatic switching when preferred-source voltage has been lost (or reduced to a predetermined level) for a period of time sufficient to confirm that the loss is not transient. The switch associated with the preferred source is automatically opened and the alternate-source switch is then automatically closed, restoring power to all loads.