Marto P.J., Wanniarachchi A.S. Heat Pipe Cooling of Large Electric Motors

Monterey: Graduate School, 1988. — 70 p.The US Navy has a continued interest in using components having greater performance-to-weight ratios than those in current use. Such efficient components would provide more space for other components that have a direct bearing on the mission capabilities of naval vessels. This is especially the case for submarines as there are severe restrictions on the size and weight of any components on board these vessels. The navy is interested in using electric propulsion for future vessels. Such vessels will require large electric motors and generators. If conventional motors (cooled by forced-air convection) are used, their size and weight may be too excessive. Therefore, to achieve the navy's goal, more efficient motors and generators, which are cooled by more advanced means, should be used. Such electric machinery may be cooled by liquids (such as water or oil) , or by two-phase heat pipes. Liquid cooling of rotors is a very challenging problem as the liquid must be forced into and out of the rotating shaft, from the stationary frame of reference. Such a scheme, of course, requires the use of rotating seals. On the other hand, such rotors may be cooled by air-cooled, heat pipes fitted near the periphery of the rotor.