318 / | HD | ELECTRICITY: MOTIVE POWER SYSTEMS |
280 | DF | MOTOR-REVERSING {4} |
287 | DF | .~ Armature or primary circuit control {2} |
288 | .~.~ Plural, diverse or diversely controlled armature windings {2} | |
289 | DF | .~.~.~> Phase-reversal |
290 | DF | .~.~.~> Selectively energized windings |