A power transforming apparatus for supplying power to a motor having a magnetic bearing includes: a converter configured to, in an initial operation, receive AC power, and an auxiliary circuit performing initial charging by rectifying the AC power to a second power and supplying the rectified second power to an inverter controller and a magnetic bearing controller. The inverter controller outputs a signal to an inverter using the second power and controls the inverter to supply a rectified DC voltage to the converter, and the converter is configured to, during a normal operation, stop supplying the second power to the inverter controller and control the rectified DC voltage to be supplied to the inverter controller and the magnetic bearing controller, and, based on a power failure being detected, outputs a control signal such that the second power is supplied to the inverter controller and the magnetic bearing controller.