US Patent 7275622 Traction elevator back-up power system with inverter timing

A back-up power system for a traction elevator includes a power sensing device to sense a power loss or irregularity of the normal control power. An inverter timing system is connected to the power loss sensing device. The inverter timing system receives a power sensing signal from the power sensing device. A back-up power generating system communicates with the inverter timing system and generates an output to provide back-up power to the elevator system.