US Patent 6920718 Independent backup power supply for a security barrier

A system is disclosed for providing a backup power supply for a security gate system. In a preferred embodiment it includes a primary power supply, an AC motor and an auxiliary DC motor that share the same accessory devices including controller, movement mechanism, sensors, communication unit, etc. The auxiliary DC motor has its own independent DC power supply. If the primary power supply fails the auxiliary power supply takes over and moves the barrier between the open and closed positions as needed without interruption of service.