Abstract: A meter for recording voltage and current on a transformer has current sensors positioned on a housing such that the meter can be mounted to the terminals of the transformer. The device also includes two voltage leads which can be attached to the transformers terminals. An instrumentation module is contained in the housing and is coupled to the current sensors and the voltage leads, the instrumentation module being adapted and configured to record voltage and current measurements from the current sensors and voltage leads. The instrumentation module includes a signal processing module for processing the voltage and current signals to provide other information such as energy and accumulated in-phase current data. Finally, the device includes a communications module coupled to the instrumentation module for communicating the voltage and current measurements and the derived data to a remote user.

Abstract: The present invention is a meter for recording voltage and current on a transformer. The device has a housing with a body portion and a lever portion, the lever portion being movable between a closed position wherein the lever portion abuts the body portion and an open position wherein the lever portion is positioned away from the body portion. The device includes a pair of current sensors each current sensor being divided into two corresponding sensor fractions with one fraction of each sensor formed on the body portion of the housing and the other corresponding fraction formed on the lever portion of the housing. The fractions of each sensors are constructed such that each of the current sensors have a central opening dimensioned to receive one of the transformer terminals when the lever portion of the housing is in its first position. The current sensors are positioned on the housing such that the meter can be mounted to the terminals of the transformer.

Abstract: A powerline communication system including a transmitter having a pair of terminals for connection to the power lines. The transmitter comprises a carrier frequency generator for generating a carrier frequency modulated by the data signal and a switching circuit connected to the carrier frequency generator for being switched by the carrier frequency generator for generating a carrier signal having the carrier frequency. The switching circuit is connected to the terminals for providing the generated carrier signal thereto. The switching circuit comprises at least one storage means for storing energy when generating a portion of a cycle of the carrier signal and providing the stored energy when generating another portion of the cycle of the carrier signal. The system also comprises a receiver coupled to the power lines.

Abstract: A device and method for monitoring the angular displacement of a rotating shaft provides an ultrasonic transceiver reflecting pulses off of a reflecting edge of a vane of a rotor affixed to the shaft. The reflecting edge is configured in the profile of an involute curve so that changes in the time delay between transmission and reception of each reflected pulse, which correspond to changes in the distance between the transceiver and the reflecting edge, are linearly related to changes in the angular displacement of the shaft, and arranged such that the reflecting edge is normal to the probe axis so that the energy is reflected back to the probe. A circular disc may be associated with the vane to provide a reference reflected pulse, which eliminates errors which might occur due to wobbling of the shaft.

Abstract: A system for tuning pianos and other string instruments utilizes a clamp-on probe with a feedback loop to induce a controlled vibration of the string and its natural frequency of vibration. This frequency is electronically compared to an accurate reference frequency. An associated electronic circuit controls an electric motor driven mechanism which adjusts the string tension until the correct frequency is achieved.