METHOD TO DRY SOLID INSULATION OF ELECTRICAL MACHINE WINDINGS Russian patent published in 2010 - IPC H02K15/12 H01F41/12 

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering, particularly to production of electrical machines and can be used in production of transformers, as well as in production and repair of motors. In compliance with proposed method, insulation in transformer tank is heated by air heat carrier and low-frequency currents on feeding 1.0 Hz-voltage to high-frequency winding, low frequency winding being short-circuited. Cyclic evacuation of said tank is effected by single- or multi-stage high-rate evacuation with the help of receiver and fast-operation electric valve for 10 seconds with subsequent holding at vacuum for up to 10.0 min, or by single- or multi-stage vacuum relief to atmospheric pressure in filling transformer tank with dehumidified air. Cycles are repeated unless required amount of humid is accumulated in solid insulation. Multi-stage evacuation prevents mechanical deformation of transformer tank and rules out origination of whatever defects in solid insulation made from multi-layer cardboards and wood board. To accelerate drying, heated vacuum cap can be used. Conditions of high-rate evacuation, receiver volume and preset pressure come-up time are calculated by enclosed formulae. Solid insulation drying can be effected on both transformer production and its operation during oil replacement.

EFFECT: intensified drying.

3 cl, 3 dwg, 1 tbl, 2 ex