Plural motor antislip drive control

Claim 1

Driving system for an electric locomotive, which driving system comprises a plurality of parallel-connected direct current motors which are mechanically connected to one pair of wheels each and connected by their armature windings to a variable alternating current source by means of rectifier diodes, each motor field being substantially independent of the armature current, a controlled current source, each motor having a field with input terminals connected to said controlled current source to receive control signals therefrom to reduce the field, each armature circuit containing means for deriving a magnitude proportional to the armature current, a selection means, said magnitude deriving means being connected by their output sides to said selection means for selection therein of the greatest of said magnitudes, a plurality of comparison means for comparing the magnitude selected by said selection means with each of the magnitudes proportional to the armature current first means connecting each of said comparing means by its input side to said selection means and one of said magnitude deriving means and second means connecting each of said comparing means by its output side to said field winding input terminals for one of said motors, and means in said second connecting means to limit the control signal to such a value that the field reduction is below a certain maximum value.