The principle of operation and the device of electricity meters

Electricity meters are used to register the consumed electrical energy. Electricity meters are induction and electronic.

Measuring mechanism of induction single-phase electricity meter (electrical measuring device of the induction system) consists of two electromagnetslocated at an angle of 90 ° to each other, in the magnetic field of which there is a light aluminum disk. The diagram of the power meter is shown in figure 1.

To connect the meter to the circuit, its current coil is connected in series with the electrical receivers, and the voltage coil is connected in parallel. When an AC induction meter is passed through the windings in the coil cores, alternating magnetic fluxes arise which, penetrating the aluminum disk, induce in it eddy currents.

The interaction of eddy currents with magnetic fluxes from electromagnets creates a force that causes the disc to rotate. The latter is connected to a counting mechanism that takes into account the speed of rotation of the disk, i.e. electricity consumption.

Rice. 1.Scheme of the device of an electric meter for measuring electric energy: 1 — current coil, 2 — voltage coil, 3 — worm gear, 4 — counting mechanism, 5 — aluminum disk, b — magnet for stopping the disk.

Rice. 2. The device of an induction electricity meter

For measuring the consumed electricity in three-phase networks with alternating current, three-phase induction electricity meters, the principle of operation of which is similar to single-phase.

Nowadays, electronic (digital) electricity meters are increasingly used... Electronic meters have a number of advantages over induction ones:

— small dimensions,

— no rotating parts,

— possibility to measure electricity at several tariffs,

— measurement of daily maximum load,

— accounting for both active and reactive power,

— taller accuracy class,

— possibility of remote electricity measurement.

Rice. 3. Scheme of the device of an electronic electricity meter

At the moment, electricity metering is mainly carried out according to the same tariff (that is, the price of electricity is the same regardless of the time of consumption). However, multi-tariff payment systems are being introduced, where the price of electricity is different by time of day or by day of the week.

This approach will ensure a more even consumption of electricity by consumers and reduce the maximum load on the electricity system. Because of this, electronic meters are now manufactured with built-in clocks that are powered by a rechargeable battery that provides electricity measurement at different time intervals set by the software.

As a rule, electronic meters have a liquid crystal indicator that shows the consumed electricity for each tariff, the current energy consumption, the current time and date and other parameters measured by the device.