Abstract: In an electrical distribution system for supplying power from an AC source to an adjustable-speed drive connected in a single-phase manner, a device for substantially eliminating harmonic currents in the supply lines of said system. The device includes a completely-passive parallel resonant circuit having three passive electrical branches connected in parallel and also having an almost infinite impendence at a third harmonic frequency of a fundamental frequency of said AC source to prevent the formation of only said third harmonic frequency so that there is no third harmonic current to remove or dissipate as heat. The three passive electrical branches comprise a first branch consisting of a capacitor, a second branch consisting of a reactor, and a third branch consisting of a resistor. The parallel resonant circuit is electrically connected to at least one supply line.

Abstract: In an electrical distribution system for supplying power from an AC source to an adjustable-speed drive connected in a single-phase manner, a device for substantially eliminating harmonic currents in the supply lines of said system. The device includes a completely-passive parallel resonant circuit having three passive electrical branches connected in parallel and also having an almost infinite impendence at a third harmonic frequency of a fundamental frequency of said AC source to prevent the formation of only said third harmonic frequency so that there is no third harmonic current to remove or dissipate as heat. The three passive electrical branches comprise a first branch consisting of a capacitor, a second branch consisting of a reactor, and a third branch consisting of a resistor. The parallel resonant circuit is electrically connected to at least one supply line.

Abstract: A device for an electrical power system having a nonlinear load. The circuit is connected in series with the nonlinear load and is tuned to the third harmonic of the power source frequency. The circuit substantially eliminates the harmonic currents and neutral currents located in the power system, and improves the power factor of the nonlinear load by optimizing the current drawn by the nonlinear load.

Abstract: In a multiple phase system for supplying power from an AC source to nonlinear loads, a device for substantially eliminating currents in a neutral wire. The device includes a completely-passive parallel resonant circuit having three passive electrical branches connected in parallel tuned to a third harmonic frequency of the AC source. The three branches comprise a first branch consisting of a capacitor, a second branch consisting of a reactor, and a third branch consisting of a resistor. The resonant circuit is connected to the neutral wire.

Abstract: In a multiple phase system for supplying power from an AC source to nonlinear loads, a device for substantially eliminating currents in a neutral wire. The device includes a completely-passive parallel resonant circuit having three passive electrical branches connected in parallel tuned to a third harmonic frequency of the AC source. The three branches comprise a first branch consisting of a capacitor, a second branch consisting of a reactor, and a third branch consisting of a resistor. The resonant circuit is connected to the neutral wire.

Abstract: An apparatus for the analysis of power quality and the effects of harmonic distortions on machinery or equipment. The apparatus is compact, portable, and non-invasive in that the apparatus can be operatively connected to an electrical carrier without power interruption. A display device is built in allowing graphical display of averaged or continuously updated measurements and analysis. A central processing unit analyzes measurements using Fourier analysis.

Abstract: A monitoring apparatus for a tuned harmonic filter is provided to prevent electrical system and filter damage. A tuned harmonic filter is provided in an electrical system to prevent overheating, motor damage, flickering lights, capacitor failure, etc. The present invention provides a sensing device in conjunction with the filter reactor to provide a signal indicative of the true operating condition of the filter. A monitoring circuit compares the signal with normal operating conditions of the filter to determine if a "fault" is occurring. Timing devices provide for a delay or rapid disconnection of the filter and/or electrical system. Indicator devices are provided to aid in diagnostic analysis of an electrical system. A remote indicator device may be included.

Abstract: A portable instrument for locating and measuring harmonic distortion in a conductor. The instrument permits voltage and current harmonics to be easily read while the load is changing. Thus, the instrument may provide a great deal of insight as to the source of problem causing harmonics.

Abstract: Energy sensing and monitoring apparatus is disclosed which can sense a plurality of energy levels in a conductor, and provide an indication when any of such energy levels is improper. The energy sensing apparatus includes an inductive device for sensing an energy level in a conductor and for providing an input signal indicative of the energy level; a comparator for receiving the input signal, comparing the input signal to a plurality of predetermined level ranges, and providing an output signal when the input signal does not fall within at least one of the predetermined level ranges; and a power source for supplying power to the comparator.

Abstract: Apparatus for detecting and indicating malfunctions of single electrical device in a group of electrical devices. The apparatus comprises an inductor connected to a common output of a group of electrical devices for providing an input signal corresponding to electrical energy in the group of electrical devices, a comparator connected to the inductor and receiving the input signal therefrom, the comparator functions to provide a default signal when at least one of the electrical devices malfunctions, a detector connected to the comparator for receiving the default signal therefrom, a timer connected to the comparator and the detector, the timer being actuated upon receipt of the default signal from the comparator and functioning to provide a timer signal to the detector means a predetermined time thereafter, and an indicator connected to the detector and being operated in response to an enable signal received therefrom.

Abstract: A portable instrument for locating and measuring harmonic distortion in a conductor. The instrument permits voltage and current harmonics to be easily read while the load is changing. Thus, the instrument may provide a great deal of insight as to the source of problem causing harmonics.

Abstract: A portable instrument for locating and measuring harmonic distortion in a conductor. The instrument permits harmonics to be easily read while the load is changing. Thus, the instrument may provide a great deal of insight as to the source of problem causing harmonics.