Abstract: A library apparatus having a motor driving control circuit including a processor, a motor driver circuit, a relay, a motor abnormal condition detection circuit, a current control circuit, an excess current detection circuit, and an abnormal current monitor circuit. The motor abnormal condition detection circuit is connected to the motor driver circuit, and detects an abnormal condition of at least one of the motor and the motor driver circuit. Upon detecting an abnormal condition, the motor abnormal condition detection circuit outputs a motor abnormal condition detection signal which prompts the current control circuit to regulate the current flowing through the motor driver circuit. If the current control circuit is unsuccessful, the excess current detection circuit outputs an excess current detection signal which triggers the relay to close the power source circuit of the motor driver circuit.

Abstract: A recording medium library system retaining up to a predetermined number of cartridge type recording media for recording/reproducing data on the recording medium is disclosed. The recording media are stored in a plurality of cells provided in a cell drum. The cell drum is rotatably driven such that a desired cell is brought to a target position. In the driving, an accelerating current, a braking current, and a positioning current are supplied to the motor in order of mention. At least the braking current is determined according to an input value of the inertia of the cell drum.