Hendry Mechanical Works

Sensata Technologies, Inc.

Other

Telect, Inc.

Michael T Parker

Christian V Pellon

Christopher A Nicolls

James J Keenan

Howard M Ham, Jr

Mark David Rabiner

Luc Pierre Benoit

Keith W Kawate

Lucien Paul Fontaine

Michael J Lavado

Roger D Mayer

Lynwald Edmunds

Jeffrey B Ting

Robert Zanelli

Robert Lee Harmon

A fluid level monitoring device and a method of use are disclosed for alerting a user that the fluid in a container, such as an intravenous (i.v.) injection or irrigation bag or collection of waste from a human body (catheter) have reached a pre-determined volume.

Fluid level monitoring system

Fluid level monitor

Low cost apparatus and methods of detecting arc faults for better discriminating electrical events. The arc fault detection apparatus includes a current sensor, a di/dt input sense circuit, a dv/dt input sense circuit, and a processing unit. The current sensor monitors a power line current, and provides high frequency components of the power line current to the di/dt input sense circuit. The dv/dt input sense circuit monitors a power line voltage. The di/dt and dv/dt input sense circuits generate signals carrying information relating to changes in the power line current and the power line voltage, respectively. The processing unit analyzes these changes in the power line current and the power line voltage to discriminate detected electrical arcing events from nuisance loads with increased accuracy.

Low cost arc fault detection technique

An apparatus and a method of detecting arc faults that have reduced susceptibility to nuisance tripping. The apparatus includes a current sensor, a differential current input sense circuit, a differential current (di/dt) characteristics sense circuit, an absolute current input sense circuit, an absolute current characteristics sense circuit, a power supply, a tripping circuit, a processing unit, and an electromechanical interface. The di/dt characteristics sense circuit provides information relating to the characteristic di/dt signature of a power line current. The absolute current characteristics sense circuit provides information relating to the absolute current waveform characteristics of the power line current. The processing unit correlates the di/dt characteristics to the absolute current characteristics to distinguish between electrical arc faults and nuisance loads, thereby reducing the susceptibility of the apparatus to nuisance tripping.

Arc fault detection technique

An apparatus and method for detecting arc faults that have reduced susceptibility to nuisance tripping. The apparatus includes a current sensor, an input sense circuit, an arcing sense circuit, a power supply, a tripping (firing) circuit, a processor, and an electromechanical interface. The current sensor monitors a power input comprising an AC current, and provides high frequency components of the. AC current to the input sense circuit. The input sense circuit filters and rectifies the AC signal, and provides the rectified signal to the arcing sense circuit. The arcing sense circuit provides a voltage level accumulated over a predetermined time period, and digital signals indicative of possible electrical arcing occurring during the sampling period, to the processor. The processor measures the voltage level, stores information relating to measured voltages and the digital signals, and processes the stored information using one or more algorithms, thereby determining whether the signals resulted from an arc fault or a nuisance load. In the event the signals resulted from an arc fault, the processor activates the firing circuit to trip the electromechanical interface, thereby interrupting the power output to the load.

Apparatus for detecting arc faults

Method for detecting arc faults

Methods and systems for reliable arc detecting in systems having power signals that experience decay or increase in amplitude. One embodiment of a system for detecting electrical arcs by monitoring an alternating current power supply comprises a sampling circuit which samples electrical signals. It further comprises a delay circuit which receives the sampling circuit output and stores a time history of the output over an interval including a past, present and future versions of the history. Causal/non-causal logic compares the present version with the past and future versions to determine which will be used as an arc monitoring version to compare the present version to for arc monitoring. A dynamic processing module compensates for any amplitude differences between the present version and the arc monitoring version. An arc monitoring circuit analyzes the present version and adjusted arc monitoring version to determine if an arc signal is present.

Arc detection method utilizing a dynamic processing module

A method and apparatus for detecting electrical arcs in an electrical system having a periodic power supply is disclosed. A method according to the invention compares instantaneous values of a monitored waveform both with (a) their past values at corresponding phases of the AC supply waveform, and (b) their future values at corresponding phases of the AC supply waveform. The monitored waveform is delayed or stored to allow such comparisons in near real time, to produce an output which is only slightly delayed behind the monitored waveform. An apparatus according to the present invention discloses a sampling circuit that samples electrical signals indicative of transient load conditions to produce a sampling circuit output. A storage device receives the sampling circuit's output and stores a time history of that output over an interval. A subtracting circuit receives the stored time history and subtract the time history from both of (a) a delayed version of the history, and (b) an advanced version of the history. An alarm circuit receives the output of the subtracting circuit.

Arc detection by non-causal signal correlation

A system for arc detection testing using synthesized arcs is disclosed, which uses voltage and current waveform generators to generate an arc's analog form voltage and current waveform from a digital form of the arc's captured waveforms. A voltage waveform amplifier and a current waveform amplifier are included, with the outputs of the voltage and current waveform generators coupled to the inputs of the voltage and current waveform amplifiers, respectively. The outputs of the voltage and current waveform amplifiers are connected in circuit to a device under test to test the device's response to the waveforms. A method for testing a device's response to a simulated arcing condition is also disclosed. An electric arc's voltage and current waveforms are captured in digital form. Analog form voltage and current waveform are generated from the captured digital voltage and current waveforms. The analog form voltage and current waveforms are applied to a device under test and the device is monitored to determine its response to the waveforms.

Electric arc synthesis for arc detector testing and method for arc testing

Electric arc monitoring is effected by exploiting the discovery that electric arcs are fractal phenomena in that all essential information that signifies &ldquo;arc&rdquo; is contained in each fractal subset. These fractal subsets are logarithmically distributed over the arc spectrum. Monitoring of arcs is most advantageously effected on a fractal subset ( ) of low logarithmic order where the amplitude is higher pursuant to the 1/f characteristic of electric arcs, where cross-induction among neighboring circuit is lower, and where travel between the arc ( ) and the arc signature pickup ( ) is longer than at the high frequencies customary for electric arc detection. Fractal subset transformation ( ) reduces the danger of false alarms. Arc signature portions may be processed in out of phase paths ( ) or treated as modulated carriers ( ) for monitoring. Aircraft may be equipped with spark monitoring systems ( ) that record ( ) occurence of dangerous sparking at different locations ( ) aboard the aircraft ( ).

Electric arc monitoring systems

Electric arc monitoring is effected by exploiting the discovery that electric arcs are fractal phenomena in that all essential information that signifies an &ldquo;arc&rdquo; is contained in each fractal subset. The fractal subsets are logarithmically distributed over the arc spectrum. Monitoring of arcs is most advantageously effected on a fractal subset of low logarithmic order where the amplitude is higher pursuant to the 1/f characteristic of electric arcs, where cross-induction among neighboring circuits is lower, and where travel between the arc and the arc signature pickup is longer that at the high frequency customary for electric arc detection. Fractal subset information reduces the danger of false alarms. Arc signature portions may be processed in out of phase paths or treated as modulated carriers for monitoring.

Systems of monitoring electric arcs substantially eliminate alternating current fundamentals and harmonics from monitored arc signatures. Such systems phase shift, delay or otherwise store a representation of the alternating current fundamental and harmonics, and substantially purge such alternating current fundamental and harmonics from the arc signatures with the stored representation of such alternating current fundamental and harmonics, while substantially preserving chaotic arc signature components. Electric arcs are then monitored from such purged arc signatures. Imperfections in such purging are detected and corrected for a provision of detectable arc signature components free of fundamentals and harmonics that could cause malfunction and false alarms.

Growing community of inventors

Camarillo, CA, United States of America

Michael T Parker