A commutator-brush combination is used as a mechanical rectifier to make the armature terminal voltage unidirectional and also to make the mmf wave due to the armature current fixed in space.

• 通过使用换流器电刷的组合作为一个机械整流器以使得电枢的端电压为单方向的同时也使得由电枢电流所产生的磁动势在空间是固定的。