| 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 |