Abstract: A vibratory apparatus including a vibratory feedbowl, a circuit for providing impulses, and a manually adjustable controller connected to the impulse circuit for providing a controlled conductance path to the impulse circuit to controllably vibrate the feedbowl. An improved controller includes a sensor connected to the vibratory feedbowl for providing a signal proportional to the actual amplitude of the feedbowl. A set point control provides a desired amplitude signal for the feedbowl. An automatic controller connected to the sensor and the set point control provides a control signal proportional to the difference between the desired amplitude and the actual amplitude. An override circuit connecting the automatic controller to the manually adjustable controller provides an override conductance path to the impulse circuit proportional to the control signal to vibrate the feedbowl at approximately the desired amplitude.

Abstract: A motor or generator having a commutator and brushes for transfer of current to and from rotor windings has a stationary conducting sensor in sliding contact with the commutator, said sensor being narrower at its contact with the commutator than the insulation between the commutator bars where contacted by the sensor, so that a sensing circuit is interrupted between the sensor and one of the brushes at a frequency proportional to the speed of the rotor.