This article discusses the variety of motor couplings used, examining proper selection, installation and alignment of the couplings, potential forces which might be generated by the couplings and their effects on the motor bearings. The consequences of sustained external loads on motor bearings is addressed for both anti-friction and sleeve bearings. Specifically, the following topics are discussed: coupling selection; proper installation and alignment of couplings; forces generated by couplings; and effects of external forces on motor bearings.