Working principle of single phase electricity meter

Single phase watt-hour meter is a kind of watt-hour meter, generally connected with 220V electric energy equipment. The main structure of the watt-hour meter is composed of voltage coil, current coil, turntable, rotating shaft, brake magnet, gears, gauges, etc. Single phase electricity meter connection is adopted in the circuit of our residential homes. The equipment of electricity consumption, single phase electricity meter has the characteristics of low energy consumption and high reliability.

Understand the principle of single-phase electricity meter, more can know how to calculate household electricity.The following small series to introduce the working principle of single phase watt-hour meter.

I. How does a single-phase watt-hour meter work?

When the watt-hour meter is connected to the circuit under test, the voltage U of the circuit under test is added to the voltage coil, forming an alternating flux in its iron core.  

Part of this flux φU passes through the aluminum disk from the return pole to the iron core of the voltage coil;  Similarly, after the measured circuit current I passes through the current coil,  

An alternating flux φi is also formed in the U-shaped iron core of the current coil. This flux is formed by U and one end of the iron core passes through the aluminum plate from bottom to top.  It then passes through the aluminum plate from top to bottom to the other end of the U-shaped core.  

The magnetic return plate is made of steel plate, and its lower end extends into the lower part of the aluminum plate, and corresponds to the iron core column across the aluminum plate and the voltage component, so as to form the voltage coil working magnetic flux loop.  

Since the two flux passing through the aluminum plate are ac flux and pass through the aluminum plate at different locations, induced vortices are generated near the location where the two flux passes through the aluminum plate.  

The interaction of the two fluxes with these eddies creates a torque on the aluminum plate that pushes the aluminum plate to rotate.

In practical application, we should choose the specification of electricity meter reasonably.  If the power meter specifications are too large, and the power consumption is too small, it will cause the meter is not accurate; If the specification is too small, it can overload the meter and can burn it out in serious cases. Generally, when choosing an electricity meter, the rated voltage is 220V, and the minimum load power of 1A electricity meter is 11W.  

Maximum load power is 440W; 2.5A single phase watt-hour meter, the minimum load power is 27.5W, the maximum can reach 1100W; 5A single-phase watt-hour meter, the minimum load power is 55W, maximum up to 2200W.

II. What should be paid attention to when installing single-phase electricity meters:

1. Check whether the seal on both ears of the cover is complete. After installing the electricity meter, close the disconnecting switch and turn on the light for inspection.

2. The meter should be installed in a dry, stable place, away from direct sunlight, humidity, heat, mildew, smoke, dust, sand and corrosive gases.The position should be correct. If there is a significant tilt, easy to cause the measurement is not accurate, stop or empty to go and other faults. The installation should be higher, but to facilitate meter reading.

3. Connect cables according to the wiring diagram and tighten screws and small hooks in the junction box.

4. Electric meter wiring tips:

4.1.When wiring, the circuit coils of the electricity meter must be connected in series on the phase line according to the schematic diagram, and the voltage coils are connected in parallel at both ends of the electrical equipment.

4.2.The generator end of the current coil and voltage coil of the meter must be connected to the same polarity of the power supply.

5. After the meter is installed, close the isolation switch and turn on the electrical equipment, the turntable rotates from left to right (the dot indicates that there is usually a steering indicator icon);  The turntable sometimes turns slightly when the electrical equipment is turned off,  

But not more than one lap is normal.