Provided with a kind of winding switching device, the motor runs with the two windings working simultaneously while underloaded, and with the multi-circle windings working solely while full loaded.

• 多匝绕组单独运行时功率大，串联少匝绕组以后的功率小，但功率因数高，效率高。电动机外部采用切换装置，轻载时，两个绕组串联运行；满载时，只用多匝绕组运行。