塑封电机普遍采用环形绕组，该绕组便于高效自动化绕线。

Circular winding is widely used in plastic - covering motor which is easy to be automatically winded.

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同时，环形绕组异步电机的结构较笼型异步电机的结构具有更好的散热性及较低的维修成本。

Meanwhile, the structure of toroidal windings asynchronous motor has better thermal diffusivity and lower maintenance costs than the structure of squirrel-cage asynchronous motor.

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本型互感器为支柱式全封闭结构，采用环形铁芯并经退火处理，一、二次绕组及铁芯用环氧树脂浇注成型。

This type of transformer is fully enclosed structure, using annular iron core and the annealing treatment. The iron core, primary and secondary windings are casted with epoxy resin.

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