Main pole as an important part of dc motor controller, mainly consists of two parts, the main pole core and the excitation winding. Below small make up to introduce it. The main pole core is 0. 5毫米~ 1。 Silicon steel plate of 5 mm thick overlying rivet, divided into polar body and the pole shoe. The part of the above set of exciting winding is very body, broaden the sections below for pole shoe. Pole shoe width in a body, can adjust the air gap magnetic field distribution in, as well as for fixed field winding. Exciting winding is used insulated copper wire winding and become, set on the main pole core. Above all, everyone to understand whether the main pole of dc motor controller.