Mike Howell, PE
EASA Technical Support Specialist

Unlike their AC counterparts, DC machines do not have rotating magnetic fields. Rather, there are fixed magnetic field axes for the field (direct axis) and armature (quadrature axis). Even though the armature is rotating, the magnetic field axis in the armature is fixed thanks to commutation, which allows the direction of current in an armature conductor to change as it passes from the region under one main field pole to the next. <br><br>LOGIN TO VIEW AND DOWNLOAD THE ARTICLE