Dc motor controller in use, depending on the situation in reverse.
But a lot of people on how to correct the inversion of don't understand, in fact way is relatively simple, small make up to you to introduce inversion method below.
To reverse connection through the armature voltage on both ends, and then change the direction of armature current.
By changing the polarity of the excitation winding, so as to make the main direction of the magnetic field change.
That is about dc motor controller inversion method is introduced, hope to help you.