[en] This paper describes a laboratory experiment using a current balance to check the calibration of an ammeter and to determine the magnetic permeability of free space. The current balance measures current by measuring the force between two parallel wires carrying that current. The results of each of the experiments are reported, and comparisons with theoretical predictions are included. The slope of ammeter reading versus measured current should be 1 and the intercept zero. The experimental values were 0.989 with an intercept of 0.25 and 1.008 with an intercept of 0.065 for current ranges from 2 to 15 A and 5 to 15 A, respectively. The calculated magnetic free space was 4.056π x 10^-7 N A^-2 and the difference between theoretical and experimental values was 1.4%

[en] The main characteristics of concrete working under the influence of electricity are considered. In this regard, concretes can be divided into two main groups: electrically conductive and electrically insulating. Both of them have the right to exist, as the development of science and technology predetermines their necessity. Various attempts were made to determine the electrotechnical properties of concrete. The article presents a fundamentally new way to study the electrotechnical properties of concrete and mortars: the “voltmeter-ammeter” method. It is proved that the measurement of the specific resistance at frequencies of 1 … 5 kHz should be considered the most appropriate for carrying out the measurements. The experiments showed that this method has the right to exist, and is one of the simplest and does not require expensive equipment. (paper)

No abstract available

[en] Highlights: •Potential noise generated by two electrodes coupled by an external resistor is analyzed. •Two values of apparent noise resistance can be obtained. •Electrode asymmetry can be evaluated. •The simplified measurement circuit does not feedback noise to the electrodes. •Results are validated by real-time imaging of the corroding surfaces. -- Abstract: The measurement of current and potential noise during corrosion generally requires two electrodes, coupled by a zero resistance ammeter (ZRA), and a reference electrode. Statistical methods then enable estimation of the noise resistance, if the electrodes are identical. In this work, a resistor is used instead of a ZRA and, consequently, the electrodes potentials are partially decoupled. This enables evaluation of electrode asymmetry and the reliability of the estimated noise resistance. Additionally, the simplification of the current-measuring circuit ensures that no instrumental noise due to active electronic components within the ZRA is fed back to the corroding electrodes

[en] Highlights: • Charge transfer between TENG and the inner capacitor of voltmeters makes the measured voltage lower than its actual value. • A general charge compensation strategy is proposed for calibrating the measured voltage of a TENG. • The FCD method and VCF method are developed to calibrate the open-circuit voltage of TENGs. • The output voltage of a TENG is calibrated through the equivalent impedance including the inner capacitance of voltmeter. The voltage is a key parameter of a triboelectric nanogenerator (TENG). However, when the voltage is measured by the voltmeters with a capacitive measurement circuit, there is a charge transfer between the TENG and the inner capacitor, making the measured voltage lower than its actual value. In this paper, a general charge compensation strategy is proposed for calibrating the measured voltage of a TENG based on the analysis of the capacitive measurement circuit. Two methods, the fixed capacitance derivation (FCD) and the variable capacitance fitting (VCF), are developed to calibrate the open-circuit voltage (V_oc) of TENGs, and the calibration formulas of V_oc are given, respectively. Firstly, a sliding freestanding triboelectric-layer mode TENG is taken as an example and the two methods are used to calibrate actual V_oc. The results are consistent with that measured by the ammeter with non-capacitive measurement circuit, verifying the validity of the charge compensation strategy. For the other three basic working modes TENGs, the measured V_oc are calibrated by the FCD method, which illustrate the universality of the charge compensation strategy. Finally, the relationship between the output voltage of a TENG and the load impedance is calibrated through the equivalent impedance including the inner capacitance of the voltmeter. The proposed charge compensation strategy for calibrating the voltage of a TENG measured by a capacitive circuit is of great theoretical and application significance for the establishment of a comprehensive evaluation system for TENG’s output performance.

No abstract available

No abstract available

[en] For the first three-quarters of this century, the monitoring of electrical power and energy has been dominated by conventional electromechanical voltmeters, ammeters, and watthour meters. Only in the last decade have solid state microprocessor-based distal devices become available for application in the commercial and industrial marketplace. These new devices perform the tasks of up to 24 conventional indicating meters for about the price of three. Communication via a RS-485 data link to a PC allows monitoring of up to 70 values including times and dates, min/max history, temperature indications, and energy management alarms. Complex waveform analysis can also be carried out for harmonic problems typically associated with adjustable speed drives that have been installed on fans and pumps for energy management savings. Since metering systems are absolutely essential to a successful Energy Management Process, consideration should be given to applying the latest in metering technology. It should be noted that meters by themselves do not save money, they only cost money to install and maintain. Proper monitoring, recording, and analysis lead to corrective actions which produce the desired result of reducing energy per unit of production or per service performed. Experience has shown that a 1 to 2% reduction can be achieved after meters are installed just by letting the users know that they are being monitored. Up to a 5% reduction can occur when the users then become proactive toward better managing of their energy. Ultimately up to 10% reduction can be achieved when metering is tied directly to the process through a PLC or DCS, in a closed loop automated process control arrangement

[en] The growing sensibility on energy consumption has focused people interest in energy optimization technologies. Non-intrusive load monitoring system (NILMS) are a cheap solution that require minimal equipment and installation time. The aim of the research is to develop a load analyzing platform for electrical devices to obtain information on their functionality and to display the costumer advantage to change their energy class. It monitors malfunctions or non-critical failures in real-time. It also counts the device operative life-time. The architecture is made of a local analysis electrical plug, which get the load information, and a central unit which elaborates data. The hardware implements a hall-effect ammeter, a power transformer and a micro controller (AT-mega328). The central unit is a small integrated computer (Raspberry). The communication between the devices utilize a low-range radio transmitter. (authors)

[en] This paper describes a universal D.C. current meter for cyclotron beam measurements. Some details of the circuit, technical data and a range of application has been given. (author)