Abstract: A circuit for regulating the amount of electrical re-charging current supplied to a battery is disclosed. The circuit includes a first generator for generating a signal representing the desired amount of the re-charging current, a second generator for generating a signal representing the actual amount of the re-charging current, and a comparator responsive to the desired and actual current signals for controlling the actual amount of the re-charging current to correspond to the desired amount. The desired signal generator includes a plurality of individual current signal sources. Each of the individual current signal sources is separately controlled by a microprocessor to selectively generate individual current signals. All of the individual current signals are summed together to provide the desired current signal.

Abstract: An apparatus and method for monitoring the operation of a hollow drive shaft is disclosed. An instrument is inserted within the shaft. A first end of the instrument includes an elastomeric retainer having a relaxed outer diameter which is slightly smaller than the inner diameter of the shaft. The retainer is compressed to expand in into frictional engagement with the inner surface of the drive shaft to retain the instrument therein. A generator is mounted within the instrument for rotation therewith. The generator includes a relatively rotatable output shaft having a pendulum attached thereto. When the drive shaft is rotated, the instrument and the generator rotate therewith, but the output shaft and the pendulum do not. Consequently, an electrical output signal is generated which is representative of the rotational speed of the shaft. Several sensors are provided to generate electrical signals representative of the torsional stress within the shaft during use and the ambient temperature therein.