| 388 / | HD | ELECTRICITY: MOTOR CONTROL SYSTEMS |
| 848 | DF | OPEN LOOP ACCELERATION CONTROL SYSTEM FOR DC MOTOR WITH COMMUTATOR {2} |
| 853 | DF | .~ Armature control {2} |
| 855 | DF | .~.~ By selectable or variable impedance {2} |
| 856 | DF | .~.~.~ By insertion of resistance or shorting of circuit {2} |
| 857 | DF | .~.~.~.~ With relay {1} |
| 858 | | .~.~.~.~.~ Time delay relay |