In the ordinary three-phase alternator set on the basis of windings,winding turns and leads to increase the lead to increase a set of three-phase bridge rectifier.At low speed,the original windings and windings are connected in series,and at the higher speed,they are only output by the original three-phase windings.The work of high and low speed power supply circuit transformation is automatic,no additional mechanical and electrical control device,its working principle is analyzed as follows:

In the low speed range,because the generator speed is low,the series output of the three-phase winding increases the output voltage of the generator,so that the low-speed charging performance of the generator is greatly improved.In the high-speed range,with the generator speed increases,the series of three-phase winding inductance increases,the internal pressure drop increases,coupled with the armature reaction to strengthen,so that the output voltage decreases.At this time the original three-phase windings A,B,C due to the smaller pressure drop,the induced current is relatively large,to ensure high-speed power out