Abstract: A method for identifying a fault condition in an electrical machine in which at least a stator or a rotor has parallel winding branches is disclosed. A measurement is carried out for obtaining a set of circulating current values between two parallel winding branches of which each winding branch includes a single coil. A frequency analysis is applied on the set of circulating current values to obtain at least one frequency component. A fault condition of the electrical machine is determined on the basis of the at least one frequency component.

Abstract: The invention is about a current transducer of the Rogowski type, with a primary conductor winding having a first number of loops (N1) for carrying the rated current (IR) to be measured, with a secondary conductor winding having a pair of second terminals and a helical shape and a second number of loops (N2), said secondary conductor winding encircling the primary conductor in a toroidal manner, whereby a rated current voltage signal VS is induced between the pair of second terminals of the secondary winding, said rated current voltage signal being characteristic for the derivative of the rated current (dIR/dt), with a transducer electronics (IED) configured to receive the rated current voltage signal (VS), characterized in that the current transducer comprises a third conductor winding having a pair of third terminals with a third number of loops (N3), whereby the transducer electronics (IED) is configured to feed a calibration current signal (ICal) into the third conductor winding, whereby in response to th

Abstract: A resistive voltage divider includes a first resistor and a second resistor electrically connected in series. Each of the resistors is made of an electrically resistive film material and applied in the form of a trace onto an insulating substrate. The divider's voltage ratio has a value between one hundred and one million, where two ends of the trace of the second resistor overlap at least in part with a first and a second) contacting terminal, respectively, and two ends of the trace of the first resistor overlap at least in part with the first and third contacting terminal, respectively. In order to decrease the parasitic capacitance between the first contacting terminal and the third contacting terminal, the second contacting terminal is placed with at least a screening part between the first and the third contacting terminals.

Abstract: A resistive voltage divider includes first and second resistors, which are electrically connected in series and are made of a resistive film material which is applied in the form of a trace onto an insulating substrate. The divider's voltage ratio has a value between ten and one million. To improve the accuracy of the voltage divider, the first and second resistors are made of the same resistive film material, have a trace length above a corresponding specific trace length, and have approximately the same trace width.

Abstract: A resistive voltage divider includes at least a first and a second resistor electrically connected in series. The resistors are made of an electrically resistive film material and each resistor is applied as a trace onto an insulating substrate. The divider's voltage ratio has a value between one hundred and one million. In order to achieve these high voltage ratios, a third resistor is electrically connected in parallel with the second resistor. The trace of the second and of the third resistor each overlap on one end at least in part with a first contacting terminal and on the respective other end at least in part with a second contacting terminal. A compact size of the divider is maintained by arranging the first and second contacting terminals in an interdigitated manner.

Abstract: An exemplary method for calibrating a current transducer of the Rogowski type including a Rogowski coil sensor and an electronic device is performed by determining and correcting the sensitivity of the current transducer of the Rogowski type through the measurement of the self-inductance LRCCT of the coil using the electronic device.

Abstract: A resistive voltage divider includes at least a first and a second resistor electrically connected in series. The resistors are made of an electrically resistive film material and each resistor is applied as a trace onto an insulating substrate. The divider's voltage ratio has a value between one hundred and one million. In order to achieve these high voltage ratios, a third resistor is electrically connected in parallel with the second resistor. The trace of the second and of the third resistor each overlap on one end at least in part with a first contacting terminal and on the respective other end at least in part with a second contacting terminal. A compact size of the divider is maintained by arranging the first and second contacting terminals in an interdigitated manner.

Abstract: A resistive structure has an improved electric field profile deposited on the surface of a cylindrical insulating substrate. At least one resistive path or trace is provided with a helix-looking shape and is directly printed on the surface of the insulating substrate. A resistive voltage divider includes first and second resistors electrically connected in series, where each resistor is made of one or more traces of electrically resistive film material applied onto a cylindrical insulating substrate. At least one of the traces is shaped like a helix and is applied onto the substrate by direct printing.

Abstract: A method for identifying a fault condition in an electrical machine in which at least a stator or a rotor has parallel winding branches is disclosed. A measurement is carried out for obtaining a set of circulating current values between two parallel winding branches of which each winding branch includes a single coil. A frequency analysis is applied on the set of circulating current values to obtain at least one frequency component. A fault condition of the electrical machine is determined on the basis of the at least one frequency component.

Abstract: An arrangement for measuring a current with a Rogowski type current transducer and transducer electronics. The current transducer has a primary conductor winding for carrying the rated current to be measured, and a secondary conductor winding. The secondary conductor winding adapted to induce a voltage signal VS? between a pair of second terminals. The current transducer having a third conductor winding adapted to receive a calibration current signal. The voltage signal VS? contains a coil sensitivity S and is a superposition of a rated current voltage signal and an additional calibration signal. The transducer electronics being adapted to amplify both the current voltage signal and the calibration signal in the same amplifier and divide the amplified current voltage signal by that part of the amplified calibration signal that contains the coil sensitivity and the gain.

Abstract: An exemplary method for calibrating a current transducer of the Rogowski type including a Rogowski coil sensor and an electronic device is performed by determining and correcting the sensitivity of the current transducer of the Rogowski type through the measurement of the self-inductance LRCCT of the coil using the electronic device.

Abstract: An exemplary electrical device for measuring alternating current or current pulses includes at least one coil of electrically conductive wire being wound around a non-magnetic carrier, where the non-magnetic carrier is made of glass.

Abstract: An exemplary current sensor operating in accordance with the principle of compensation includes a primary winding creating a magnetic field based on a current to be measured, a secondary winding generating a magnetic field compensating the primary winding based on a compensation current. The current sensor also includes a magnetic core, a terminating resistor connected in series to the secondary winding, and sensor means. A booster circuit is connected downstream of the sensor means and feeds the compensation current to the secondary winding via the terminating resistor. The booster circuit includes a switched mode amplifier with a pulse width and density modulator that operates based on pulse width and density modulation, turning the compensation current into a pulse width and density modulated current. The switched mode amplifier having a switching frequency that is high at when the compensation current is small and low when the compensation current is high.

Abstract: A resistive structure has an improved electric field profile deposited on the surface of a cylindrical insulating substrate. At least one resistive path or trace is provided with a helix-looking shape and is directly printed on the surface of the insulating substrate. A resistive voltage divider includes first and second resistors electrically connected in series, where each resistor is made of one or more traces of electrically resistive film material applied onto a cylindrical insulating substrate. At least one of the traces is shaped like a helix and is applied onto the substrate by direct printing.

Abstract: A phase-locked loop is provided for estimating a phase angle of a three-phase reference signal. The phase-locked loop includes a device for calculating an estimated first state and an estimated second state at a fundamental frequency on the basis of the reference signal and the estimated fundamental frequency, a device for calculating a fundamental positive sequence component of the reference signal on the basis of the first state and the second state, a device for calculating a direct component and a quadrature component in a reference frame synchronous with the phase angle on the basis of the fundamental positive sequence component and an estimated phase angle, and a device for determining estimates of the estimated fundamental frequency and the estimated phase angle on the basis of the quadrature component.

Abstract: A resistive voltage divider includes a first resistor and a second resistor electrically connected in series. Each of the resistors is made of an electrically resistive film material and applied in the form of a trace onto an insulating substrate. The divider's voltage ratio has a value between one hundred and one million, where two ends of the trace of the second resistor overlap at least in part with a first and a second) contacting terminal, respectively, and two ends of the trace of the first resistor overlap at least in part with the first and third contacting terminal, respectively. In order to decrease the parasitic capacitance between the first contacting terminal and the third contacting terminal, the second contacting terminal is placed with at least a screening part between the first and the third contacting terminals.

Abstract: A resistive voltage divider includes first and second resistors, which are electrically connected in series and are made of a resistive film material which is applied in the form of a trace onto an insulating substrate. The divider's voltage ratio has a value between ten and one million. To improve the accuracy of the voltage divider, the first and second resistors are made of the same resistive film material, have a trace length above a corresponding specific trace length, and have approximately the same trace width.

Abstract: A current sensor is disclosed, with a ring-shaped magnetic core, the core enclosing the primary conductor with the current to be measured, the core having an air-gap containing a sensor element for measuring the magnetic core induction, whereby the cross-sectional area of the air-gap is larger than the cross-sectional area of the core.

Abstract: An exemplary current sensor operating in accordance with the principle of compensation includes a primary winding creating a magnetic field based on a current to be measured, a secondary winding generating a magnetic field compensating the primary winding based on a compensation current. The current sensor also includes a magnetic core, a terminating resistor connected in series to the secondary winding, and sensor means. A booster circuit is connected downstream of the sensor means and feeds the compensation current to the secondary winding via the terminating resistor. The booster circuit includes a switched mode amplifier with a pulse width and density modulator that operates based on pulse width and density modulation, turning the compensation current into a pulse width and density modulated current. The switched mode amplifier having a switching frequency that is high at when the compensation current is small and low when the compensation current is high.

Abstract: A measuring instrument to capture a physical/chemical measured value, including a sensor unit, which is linked via a contactless interface to a transmitter unit, for passing on to a central analysis unit, wherein the sensor unit includes an at least partly internal sensor element which vibrates against a sensor housing because of operation, and which is linked, contactlessly and inside the sensor unit, for sensor signal transmission, via a first transmission/reception unit, to a complementary second transmission/reception unit, which is arranged at a fixed location relative to the sensor housing, and which is also linked, contactlessly and outside the sensor unit, to a third transmission/reception unit of the transmitter unit.