A CT system includes a gantry having a rotatable base and having an opening for receiving an object to be scanned and an AC to DC converter coupleable to a 3 phase AC facility power and coupled through a DC bus to a gantry motor to rotationally drive the rotatable base using DC power from the AC to DC converter. Rotational energy in the rotatable base is converted to DC electrical energy in the gantry motor during gantry braking and provided to the DC bus.