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Losses by Windage and Friction (Mechanical Losses)

Author: E.E. Kimberly

Power losses caused by air friction depend to a large extent on the shape of the armature (projecting parts, etc.), and are approximately proportional to the cube of the speed. Some directed blower action for cooling the generator is frequently provided by fan blades attached to the armature near the windings. The additional windage loss is more than compensated for economically by the greater output possible because of the added cooling.

Friction loss in sleeve bearings with oil rings is independent of the load, and is proportional to the three-halves power of the speed. Brush friction loss is proportional to the speed and is independent of the load.

Last Update: 2010-10-05