| 310 / | HD | ELECTRICAL GENERATOR OR MOTOR STRUCTURE |
| 300 | DF | NON-DYNAMOELECTRIC {4} |
| 311 | DF | .~ Piezoelectric elements and devices {17} |
| 321 | DF | .~.~ Combined with resonant structure {4} |
| 323.01 | DF | .~.~.~ Direct mechanical coupling {5} |
| 323.02 | DF | .~.~.~.~ Motor producing continual motion {3} |
| 323.03 | DF | .~.~.~.~.~ Traveling wave motor {3} |
| 323.08 | | .~.~.~.~.~.~ Armature {1} |
| 323.09 | DF | .~.~.~.~.~.~.~> Pressing means detail |