| 摘要 |
PURPOSE:To reduce the drying period of a leaf-wound coil and to prevent the deterioration in efficiency of an insulating sheet caused by heating by a method wherein a high frequency vacuum drying operation is performed before the insulating sheet and a metal sheet are lap-wound. CONSTITUTION:The insulating sheet 10 before winding is wound in roll form on a winding core 15. Metal cylinders 11a and 11b are attached to the inside of the winding core 15 of said insulating sheet 10 and the outside of the insulating sheet 10, they are placed in a container 12 which can be evacuated, the container 12 is evacuated using a vacuum pump 13 connected to the container 12, the container 12 is connected to a high frequency wave generator 14 using the metal cylinders 11a and 11b attached to the insulating sheet 10, and a high frequency vacuum drying operation is performed. Moisture is uniformly removed from the insulating sheet 10, on which a high frequency vacuum drying operation is performed, and as it is not subjected to a high temperature because it is dried up in a vacuum state, its mechanical strength is not deteriorated and also thermal deterioration is not generated. As a result, the drying period after coil is wound can be cut down, and there is no possibility of having thermal deterioration on the insulating sheet 10.
|
