The Difference Between a Three-Phase Meter and a Single-Phase Meter
A three-phase watt-hour meter is used to measure the electrical energy output by a power supply (or consumed by a load) in a three-phase AC circuit. Its working principle is the same as that of a single-phase watt-hour meter, except that it uses multiple sets of driving components and multiple aluminum disks fixed on the rotating shaft in structure to measure three-phase electric energy.
Single watt-hour meter
Single-phase watt-hour meter, applied to active power metering: accurate metering, modular and small size (18mm), can be easily installed in various terminal distribution boxes. DIN-rail mounting, bottom wiring, perfectly matched with miniature circuit breakers. Intuitive and easy-to-read mechanical display reduces the risk of data loss in unexpected power outages. No external power supply is required, and the operating temperature range is wide. It is suitable for commercial buildings and public infrastructure buildings to realize the measurement and statistics of power consumption in different areas or different loads in the building. It is suitable for power consumption statistics and internal accounting of different production lines or various loads in industrial buildings.
How a three-phase watt-hour meter works
A three-phase watt-hour meter is used to measure the electrical energy output by a power supply (or consumed by a load) in a three-phase AC circuit. Its working principle is exactly the same as that of a single-phase watt-hour meter, except that it uses multiple sets of driving components and multiple aluminum disks fixed on the rotating shaft in structure to measure three-phase electric energy.
According to the nature of the measured electric energy, three-phase watt-hour meters can be divided into active watt-hour meters and reactive watt-hour meters; due to the different wiring forms of three-phase circuits, there are three-phase three-wire system and three-phase four-wire system. The following briefly introduces some characteristics of the three-phase active watt-hour meter.
The difference between the three-phase four-wire active watt-hour meter and the single-phase watt-hour meter is that it consists of three driving elements and three aluminum discs mounted on the same shaft, and its reading directly reflects the electrical energy of three-phase consumption. There are also some three-phase four-wire active watt-hour meters that use three sets of driving components to act on the same aluminum plate. This structure has the advantages of small size, lightweight, reduced friction torque, etc., which is conducive to improving sensitivity and prolonging service life, etc. However, since 50 sets of electromagnetic elements act on the same disc, the mutual interference of the magnetic flux and eddy current will inevitably increase. Therefore, compensation measures must be taken to increase the distance between each group of electromagnetic elements as much as possible. Therefore, the diameter of the turntable is correspondingly larger.
The three-phase three-wire active watt-hour meter adopts a structure in which two sets of driving components act on two aluminum disks (or one aluminum disk) mounted on the same rotating shaft. The principle is exactly the same as that of the single-phase watt-hour meter.
