An induction energy meter with an electromechanical device for calculating energy consumption is still a reliable device installed in residential premises. Users are attracted by its reliability, ease of maintenance, long life and low cost.
Induction Meter Design
The main components of an induction electric meter are the electromagnets of voltage and electric current. During their interaction, an electromagnetic field appears along with the magnetic circuits included in them. Through the transmission device, the field acts on the aluminum rotation disk.
The current electromagnet experiences heavy loads during operation, so its winding is made of a large cross-section wire. The number of turns does not exceed thirty. The wire is evenly wound on two magnets, which are connected in series with the clamps to the network.
The voltage coil is connected in parallel to the network and creates an electromagnetic field that is directly proportional to the effective voltage. The coil winding is made of thin wire with a cross section of 0.1 ... 0.15 mm². The number of turns can reach 12000, which allows you to create inductive resistance more than active. Such a device can reduce energy consumption during operation of the meter.
All components of a single-phase mechanical meter are housed in a plastic case. Data on electricity consumption for the current period is displayed on a digital drum. The energy consumption rate can be determined by the value of the disk rotation speed.
How does an induction meter work?
The aluminum disk of the induction electric energy meter is a movable conductive element, which is affected by the electromagnetic field created in the coils of the meter. As a result of their action, a magnetic field arises, alternating in direction and acting on the disk, in which eddy currents are created that coincide in direction with magnetic fluxes.
An interaction takes place between eddy currents and magnetic fluxes, which creates a torque that varies in magnitude and causes the aluminum disk to rotate. A relationship is created between the torque and the total magnetic flux from two current and voltage coils, taking into account a 90º phase shift and feedback. To obtain a phase shift, the magnetic flux of the voltage electromagnet is decomposed into two parts.
Under the influence of torque, the disk rotates with a frequency depending on the amount of incoming energy. The axis of the disk is connected to the counting device of the digital drum, which reflects the actual amount of energy consumed.
Pros and cons of appliances
The old-type disk electric meter has several advantages over the new electronic models of meters that are actively being introduced into residential buildings:
- have a high degree of reliability;
- simple execution scheme and principle of operation;
- the cost of an old-style electric meter is lower than an electronic one;
- indifferent to possible voltage drops of the electric network;
- have a long service life.
At the same time, electromechanical meters have a number of disadvantages, which include:
- Low accuracy class of electric energy metering, especially at low loads.
- Only one tariff is used to pay for electricity, while most electric companies provide different prices for electricity during the day and night.
- The ability to stop the rotation of the disk, and even rewind indicators back, which unscrupulous users can take advantage of. Disk stop is also possible in the event of a breakdown.
All the disadvantages inherent in induction products are known to manufacturers. They are constantly working to modernize and improve the quality of their products, increasing the accuracy class and service life. However, the design features do not allow to fully realize all these useful necessary conditions in the device. Therefore, in place of induction devices come more advanced, electronic.
Do I need to change the counters to new
If you have an old induction meter installed, do not rush to change it to a new one. It is possible that he will serve for a long time, until the end of the service life specified in the passport, and this is almost 20 years. However, in some cases they may be forced to make a replacement and you will be required to purchase a new counter.
Electric meters are subject to replacement in such cases:
- Work is underway on a scheduled upgrade of the electrical network with the replacement of all meters.
- The counter is defective.
- The instrument has expired according to the data sheet.
By law, the user does not have to install an electronic meter when replacing. If it is convenient for him, he can supply any induction energy meter, the main thing is that the accuracy of the measurements comply with the requirements of the law: the accuracy class should be 2.0 and higher.
Payment for the purchase of the meter and its installation is borne by the owner, unless a planned replacement is made. In some cases, ownership of the device requires clarification:
- When the meter is installed in the apartment, homeowners are required to monitor the technical condition of the device, take readings and replace if necessary. All expenses are borne by the tenants of the apartment.
- When an old-style electric meter is installed in a common corridor, and it is used by several apartments, the device is the common property of all owners. The costs of replacing it will be borne by all parties. If it is stipulated by the contract with the service company, the company itself changes the counter at the expense of the collected funds.
- When the meter is owned by an energy company licensed to carry out such work, the replacement is done at its expense.
If there is no good reason to change the electricity meter, the requirements of the inspection authorities for replacement are not legal. In this case, the meter must be in good condition, not expired.
Tariff accounting system
The most significant drawback is the inability to use several tariffs to pay for electricity. Therefore, the need to change the old electric meter to a new one depends on how the energy consumption changes during the day. If there is significant consumption at night, it makes sense to switch to a more modern electronic meter. True, you should take into account the cost of buying and installing a new electronic meter.
Reading
Electromechanical meters are equipped with a digital drum, which displays the energy consumption in kilowatts. These data can be submitted to the billing service or to make calculations yourself.
Depending on the model, 5 or 7 digits appear on the drum scoreboard, the latter being separated from the rest by a comma and highlighted in color. When accounting, you do not need to count tenths and hundredths of kilowatts - only integers.The resulting consumption of kilowatts per month is multiplied by the cost of 1 kilowatt and get the amount that must be paid for electricity.
