An emergency power supply for a traction elevator system utilizes a microprocessor-based control arrangement with pulse-width modulator technology to create an efficient, cost-effective back-up power system for a traction elevator. The microprocessor-based control arrangement is used to sense a power loss, or any type of irregularity in the power supply. Upon sensing some type of power malfunction, the microprocessor-based control arrangement disconnects the elevator system from the main power source and then generates a control signal to initiate the supply of back-up power. Once the elevator electrical system has been recharged and stabilized, the elevator control system will sense that recovery has occurred and will then provide an appropriate speed and direction command to the traction motor drive system.