A simple rugged motor has a stator and a rotor formed by stacked silicon steel sheets operates by having a plurality of major and minor coil windings of the stator individually electrified under signals of a control unit, so as to steadily drive a rotor thereof. The simple rugged motor further has an orbit coupling balance assembly engaging an orbiting scroll for a corresponding fixed scroll disposed in a compression chamber to orbit for air compression, so as to form a scroll compressor. Or the simple rugged motor has a coupling assembly engaging a female screw compressor rotor to compress the air by a rotatable male screw compressor rotor disposed in a compression chamber, so as to form a screw compressor.