All hydrodynamic bearings require a continuous supply of cooled lubricant. In die case of large, high speed electric motors for industrial applications, oil is most commonly provided by an external lubrication system design to API or equivalent specifications. This paper describes the design and some of the experimental work done in the development of a new range of self contained, air cooled bearings designed to eliminate the need for such costly external lubrication systems. Experimental work was carried out using a 140 mm shaft diameter test bearing operating at a range of duties up to a maximum specific load of 2.07 MPa and a maximum speed of 4500 rev/min. Measurements made include those for oil delivery against speed utilising an innovative, dual mode oil ring described in the paper. © 1995 Elsevier Science B.V. All rights reserved.