279results about "Voltage polarity indication" patented technology

Provided is a system, a tool and a method for communicating with a faulted circuit indicator (FCI), the faulted circuit indicator including a detection circuit for monitoring an electrical conductor of a power system. The system includes a remote display mounted in a wall of an enclosure and visible from outside of the enclosure and a first light emitting diode associated with the remote display. The first light emitting diode generates an optical FCI status signal in response to an occurrence of a fault in the electrical conductor. The system also includes a first microcontroller operatively coupled to the remote display and the detection circuit, and a handheld user command tool adapted to optically couple with the remote display. The handheld user command tool is also adapted to generate an optical serial communication. The optical serial communication provides data and commands for operation of the faulted circuit indicator.

A multimeter with a filtered measurement mode. By pressing a single button or key, a low-pass filter is switched into the signal path to filter voltage spikes, noise, and switching transients from pulse-width modulated pulses, or lower frequency sinusoidal signals with higher frequency components, and at the same time an on-screen icon indicates to a user that the filtered mode has been selected. The user can switch back and forth between filtered and unfiltered modes. The filtered measurement mode is useful in measuring the outputs of modern adjustable-speed motor drives, uninterruptible power sources, and switch power supplies.

A semiconductor leakage current detector of the present invention includes a first analog switch which causes a current to be measured to flow or to be cut off, a second analog switch which causes a reference current to flow or to be cut off, an integral capacitance element which is connected by the first analog switch and the second analog switch and is charged with the current to be measured or the reference current, a discharge unit which discharges the integral capacitor, and a comparison unit which compares the reference voltage with each of an integral voltage generated in the integral capacitor by a reference current after the discharge of the integral capacitor and an integral voltage generated in the integral capacitance element by the current to be measured after the discharge of the integral capacitor.

In an inverter circuit including switching devices and diodes connected in parallel with the switching devices which are provided in pairs of upper and lower arms, and also including resistances for detecting phase currents in a motor connected to the lower arms, during dead time periods when both a switching device in an upper arm and a switching device in a lower arm are off, a voltage across a phase-current detection resistance induced by a phase current flowing through a diode is sampled.

A mobile apparatus for monitoring an electric field in a patrolled area, comprising at least one detection device for measuring electric field signals, at least one camera device for collecting video images of said patrolled area, a processor for correlating video image data collected from the camera device with electric field signal data measured by the detection device, and a video based graphical user interface for analyzing and capturing a monitored event depicting an anomaly in the measured electric field signals.

The present invention is an attachment device and a method for fastening and removing an electrical cable monitoring instrument to an electrical cable. The attachment device comprises monitoring instrument sensor with opening for positioning electrical cable such that said electrical cable can be positioned to pass through the sensitive volume at least partially surrounded by said sensor, at least one elongated elastic member securely attached to said cable monitoring instrument such that, when elastically deformed to a shape characterized by high mechanical energy such that deformed elastic member allows said electrical cable access to and from the sensitive volume at least partially surrounded by said monitoring instruments sensor. The elongated elastic member, when relaxed to the a shape characterized by lower mechanical energy than high mechanical energy shape, with the electrical cable positioned to pass through sensitive volume, applies elastic force to the electrical cable to hold the electrical cable passing through the sensitive volume firmly and securely in contact with the cable monitoring instrument with no relative motion.

A probe apparatus disclosed for use in a separable connector includes an insulating body and spaced apart first and second electrical conductors in contact with the insulating body. The first and second electrical conductors have adjacent surfaces configured such that when an electrical potential is applied between the conductors, an electric field is formed between the conductors. The insulating body has an opening positioned between the conductors and adapted to receive a sensor such that a portion of the sensor is subjected to the electric field. A separable electrical connector system is described including the probe apparatus, as is a voltage sensing system including the probe apparatus and a voltage sensor positioned within the opening of the insulating body.

A phase current prediction method is disclosed. The phase current prediction method predicts current representative of a PWM period using a motor model which receives current measured through a single current sensor as an input, instead of the measured current, and determines the predicted current to be phase current.