Various physical conditions of the friction surfaces were studied to increase the breakaway torque of the electromagnetic clutch for the automotive air conditioning compressor. The conventional ground steel-ground-steel combination had a disadvantage of low breakaway torque in the running-in period of engagement cycles. This situation was greatly improved by using the combination of the ground armature plate and the machined rotor with zinc plating. In this new technique, the pitch and depth of the machining mark relative to the plating thickness was found to be important. Combinations of machined armature plates and the machined rotors, with or without zinc plating, were also promising, and the mechanism of friction with these surface combinations were analyzed.