Abstract: A power management system and method for multiple redundant power supplies. The present invention provides management and control of N+M power supplies, where N represents the minimum number of power supplies required and where M is the number of redundant power supplies (M>1), where any one of the power supplies may be capable of supplying power to all the loads of the power subsystems. In the preferred embodiment each power subsystem includes a power supply and a controller coupled to a power bus. A communication bus is provided common to each power subsystem. During reset or power-on periods, the controllers are programmed to uniquely delay the start time of each power supply, thereby protecting against an overcurrent/overvoltage condition on the power bus during reset periods. A master controller is provided to monitor normal operating conditions of the power subsystems and communication bus.

Abstract: A power limiting system and method are provided for limiting power delivered to a common bus in a one or multi-frame tape library environment. The system includes one or more frames coupled to a common bus, each of which is capable of delivering power to the common bus. Each frame comprises current limiting circuitry to limit the power delivered by that frame to the common bus. In exemplary embodiments, the current limiting circuitry of each frame includes a current limiting resistor and a blocking diode coupled to a local power source to limit the power delivered by that frame and to prevent feedback respectively. Additionally, each frame of the system includes a relay capable of receiving a limited power from the common bus, being energized, and, consequently, providing for the respective frame to be powered by a main power supply.