ROTATING ELECTRICAL MACHINE AND ITS COOLING TECHNIQUE Russian patent published in 1999 - IPC

FIELD: electrical engineering. SUBSTANCE: air- cooled machine has open cooling circuit with mechanically filtered atmospheric air forced by means of fans installed on either side of rotor shaft through cooling ducts to stator, rotor, air gap, and then released back into atmosphere. Novelty is that only cooling air admitted to rotor is additionally filtered. Mechanically filtered air forced to stator and, when necessary, to air gap of machine is conveyed by means of fans and to rotor cooling air is passed over separate path. Machine has open-circuit cooling system with cooling ducts in rotor and stator frame, machine casing with external jacket, fans on both ends of rotor shaft, air-feed chambers isolated from internal part of machine by means of linings. According to invention, chambers are divided by first internal barriers and first chamber formed by external jacket and first internal barrier is designed to feed additionally filtered air directly to rotor bypassing the fan. Second chamber formed by first and second internal barriers can only feed pre-filtered cooling air. Machine is also provided with means for separating winding head space from rotor space. EFFECT: reduced investment in additional filter as only small portion of cooling air needs additional filtering. 7 cl, 3 dwg