Electrical metering

Ni alloys of 30—32 wt % are used as temperature-compensator alloys and are characterized by a steep decrease ia magnetic permeabiUty with temperature. These alloys are ideally suited ia electrical circuits as shunts which maintain constant magnetic strength ia devices such as electric meters, voltage regulators, and speedometers. 

Instruments based on the contact principle can further be divided into two classes mechanical thermometers and electrical thermometers. Mechanical thermometers are based on the thermal expansion of a gas, a liquid, or a solid material. They are simple, robust, and do not normally require power to operate. Electrical resistance thermometers utilize the connection between the electrical resistance and the sensor temperature. Thermocouples are based on the phenomenon, where a temperature-dependent voltage is created in a circuit of two different metals. Semiconductor thermometers have a diode or transistor probe, or a more advanced integrated circuit, where the voltage of the semiconductor junctions is temperature dependent. All electrical meters are easy to incorporate with modern data acquisition systems. A summary of contact thermometer properties is shown in Table 12.3. 

A Southern California Edison employee logs test results at the company s electric meter site. tCorbis-Bettmann)... 

The assessment stage requires a breakdown of all the costs involved in running the plant, i.e. not only all fuels, but also the costs of operation, maintenance and spares. At this stage it maybe helpful to fit separate electricity meters to sections of the plant under survey, so as to identify their individual fuel costs. Many of the overall expenses will be mixed, but an effort must be made to apportion these to the areas under examination. At the same time, the running conditions and methods are noted. 

From then we just lived really, really poorly. I mean. I ve got a gas meter and an electricity meter but when people came down they said the house was freezing. To us it was just... If we were cold we would put jumpers on and things like that. And my shopping... We never went without, but it was just cheaper brands. We had to cut corners some way. I mean there was no McDonalds and no just jumping to the pictures [cinema]. For the last three years that s the way it s been. Having to watch every penny. 

For people who purchase small wind turbines for their home, unused electricity causes their electric meter to run backwards As this happens, the... 

Solar installations are often supported by federal and state subsidies, and many power companies allow these systems to be connected to their electricity grid so that the excess power generated can be sold to the power company for a credit (the electric meter is running backward), which "electricity credit" can be used later when solar energy is not available. In Europe, the highest amount of support paid is in Germany. In the United States, California supports each installation with about 25,000. In New York, the state pays 49-70% of the cost in New Jersey, support is 3,800/kWp and in Connecticut, 25,000 per installation. 

In the renewable energy processes, electric meters are required to determine the rate of power generation, the flow of electricity to and from the grid, and the efficiencies of solar collectors, wind turbines, electrolyzers, and fuel cells. Peak shedding is used to increase the cost-effectiveness of the total operation. 

Table 3.54 gives a summary of the features and applications of the current, voltage, and wattage instruments. Some of these electric meters have been... 

Another optimistic assumption is that the pem system will be used with net metering When the system is generating more electricity than the home is using, power is returned to the electric grid and the electric meter runs backward, every homeowner s hope. As of 2003, about half of the states had net metering for residential power systems such as photovoltaics and fuel cells. 

Many standard lab activities use simple measuring devices such as a thermometer, a clock (or wristwatch, chronometer or stopwatch), a ruler (or micrometer or tape measure), or an electrical meter (e.g. voltmeter, ammeter). Humidity is measured with a hygrometer. 

Many houses have a water meter, an electricity meter and a gas meter. 

The mercury coulometer has been employed chiefly for the measurement of quantities of electricity for commercial purposes, e.g., in electricity meters. The form of apparatus used is shown in Fig. 5 the anode consists of an annular ring of mercury A) surrounding the carbon cathode (C) the electrolyte is a solution of mercuric iodide in potassium iodide. The mercury liberated at the cathode falls off, under the influence of gravity, and is collected in the graduated tube Z). From the height of the mercury in this tube the quantity of electricity passed may be read off directly. When the tube has become filled with mercury the apparatus is inverted and the mercury flows back to the reservoir J . In actual practice a definite fraction only of the current to be measured is shunted through the meter, so that the life of the latter is prolonged. The accuracy of the mercury electricity meter is said to be within 1 to 2 per cent. 

In a typical experiment the ozonator was operated at some energy input level which would be expected in normal installations. At least 30 minutes were allowed to establish steady-state conditions. The readings of flow rate meters, associated pressures, and temperatures as well as electrical meters were recorded. The samples of the inlet ozonator gases were analyzed for composition samples of ozonator output gases were analyzed for ozone concentration. 

Calibration is at the heart of chemical analysis, and is the process by which the response of an instrument (in metrology called indication of the measuring instrument ) is related to the value of the measurand, in chemistry often the concentration of the analyte. Without proper calibration of instruments measurement results are not traceable, and not even correct. Scales in supermarkets are periodically calibrated to ensure they indicate the correct mass. Petrol pumps and gas and electric meters all must be calibrated and recalibrated at appropriate times. 

Heat meter- An electrical municipal inspection of the electric meter breaker panel box. 

Printed circuit boards that are operated in an aggressive environment need special corrosion protection. A particularly acute need exists in commercial utility meters, such as natural gas meters, water meters, or electric meters. In addition, there may be the demand for repair and reapplication... 

The arrangement form used in the electrode cables buried inside seam roof, electrical meter installed in the tunnel behind, linked ground monitoring station through the underground cable. 

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