Abstract: The electromagnetic clutch illustrated is adaptable for use with an air-conditioning compressor and includes a rotatable electromagnetic coil and pulley assembly and an armature plate which form part of a 4-pole magnetic flux path. A slip ring is secured to the coil housing, and a spring-loaded brush means is secured to the compressor for sliding engagement with the slip ring. A clutch rotor is secured to an end of the inner coil housing wall adjacent the armature plate and extends radially outwardly from said inner wall so as to provide an uninterrupted circular air space with the outer coil housing wall adjacent the armature plate, such that no shorting of the lines of flux can occur from the end portion of the outer wall to the clutch rotor, providing a faster and stronger attraction of the armature plate when the electromagnetic coil is energized.