The present invention provides a compressor that includes: one or more impellers that axially suck and centrifugally compress a refrigerant; a rotary shaft that is connected with the impeller and a motor for rotating the impeller; a plurality of magnetic bearings that supports the rotary shaft in the air so that the rotary shaft can rotate; a gap sensor that senses the distance from the rotary shaft; and a controller that determines abnormal wire connection of the magnetic bearings on the basis of information from the gap sensor. The controller can sense movement of the rotary shaft through the gap sensor while controlling the amount of current supplied to any one of the magnetic bearings and can determine whether there is abnormal wire connection on the basis of the information.