GB301838A - Improvements in or relating to dynamo-electric machines - Google Patents

Abstract

301,838. Baum, F. G. Dec. 6, 1927, [Convention date]. Armatures and field magnets, cooling; enveloping in special media.-An enclosed machine has one or more stationary pockets in its casing and means whereby a cooling liquid is transferred centrifugally to the pocket from a reservoir in the bottom of the casing; it then flows from the pocket back to the reservoir through ducts in the stator and rotor, the cycle being continuously maintained. The cooling liquid is preferably oil which, during the cycle, is broken up into mist and with an admixture of air or other gas forms a cooling medium of greater specific heat than the pure gas. When carbon dioxide, nitrogen or other non-inflammable gas is used in place of air. fire risk in the machine is reduced. Figs. 1 and 2 show a form in which the reservoir 16 at the bottom of the enclosed stator space contains oil which is cooled by a water-coil 35 and is lifted by arms 18, rotating with the rotor 2, into one or other of two pockets 19, 20 in the stator frame in accordance with the direction of rotation. From the pockets the oil passes through inclined pipes 14, 23 to troughs 22 secured between the edges of the pole-pieces 3, and it emerges in a nnely-divided state from openings 24 in the bottoms of the troughs preferably located opposite the ducts 8 between the stator laminae. The gas or air within the casing is mixed and circulated with the oil by fan blades 13 on the rotor and gas passages may also be formed through the rotor poles or between them. Fig. 4 shows the application to a squirrel cage machine in which oil from the pockets passes through pipes 14<1>, 23<1> to a trough 30 formed inside the rotor and is then flung out centrifugally through openings 27 in the rotor iron containing spraying devices, such as jet plugs positioned within and near their outer ends.