Energy meters are an essential part to live facility consumption. It is used everywhere, regardless of how big or small consumption it’s. It is also known as a watt-hour meter. Here we discuss the development and dealing principle of induction type energy meter.
To have an understanding of the structure of a watt-hour meter, we must understand the four essential components of the meter. These components are as follows:
1. Driving system
2. Moving system
3. Braking system
4. Registering system
The components of this technique are two silicon steel laminated electromagnets. The upper electromagnet is named shunt magnet and it carries a voltage coil consisting of the many turns of thin wire. The lower electromagnet is named series magnet and it carries the 2 current coils consisting of a couple of turns of thick wire. Current coils are connected in series with the circuit and load current passes through it.
Whereas the voltage coil is connected to the availability of mains and produces a high ratio of inductance to resistance. There are copper bands within the lower a part of the shunt magnet which provides frictional compensation so that the phase between shunt magnet flux and therefore the supply voltage is exactly 90.
There’s a skinny aluminum disk placed within the gap between the 2 electromagnets and mounted on a vertical shaft. The eddy currents are induced within the aluminum disk when it cuts the flux produced by both the magnets. As a result of interference of eddy currents and two magnetic fields constitute a deflecting torque in the disk.
As you begin consuming power the disk slowly starts rotating and therefore the several rotations of the disk display the facility consumption, within the particular interval of your time. Normally it is measured in kilowatt-hours.
The main part of this technique may be a static magnet called a brake magnet. It is located near the disk so that eddy currents are induced in it thanks to the movement of rotating disk through the magnetic flux. This eddy current reacts with the flux and it exerts a braking torque. The speed of the disk is often controlled by changing flux.
As its name suggests, it registers the amount of rotation of the disk which is proportional to the energy consumed directly in kilowatt-hour. There is a disk spindle that is driven by a gear on the disk shaft and indicates the number of times the disk has turned.
Working Principle of Energy Meter
The working of single-phase induction type energy meters are supported two main fundamentals:
1. Rotation of aluminum disk.
2. Arrangement of displaying and counting the amount of energy consumed.
Rotation of an Aluminum Disk
The rotation of the metallic disk is being operated by two coils. Both the coils are arranged in such a way that one coil produces a magnetic flux in proportion to voltage and therefore the other coil creates a magnetic flux proportional to the current. The field produced by a voltage coil is delayed by 90o so that eddy current is induced within the disk. The force exerted on the disk by the 2 fields is proportional to the merchandise of the immediate current and voltage within the coils.
As a result of it, a lite weight aluminum disk rotates in an air gap. But there’s a requirement to prevent a disk when there’s no power supply. A static magnet works as a brake which opposes the rotation of the disk and balances the speed of rotation with reference to power consumption.
Arrangement of Counting and Displaying the Energy Consumed
In this system, the rotation of the floating disk has been counted then displayed on the meter window.
The aluminum disk is connected to a spindle that features a gear. This gear drives the register and therefore the revolution of the disk has been counted and displayed on the register which has a series of dials and every dial represents one digit. There is a little shop window within the front of the meter which displays the reading of energy consumed with the assistance of dials. There is a copper shading ring at the central limb of the shunt magnet. To make the phase between flux produced by shunt magnet and provide voltage about 900, small adjustments within the place of the ring is required.
Electric Motor Energy Meters
Electric Motor Energy Meters are known by their name that these energy meters contain a little motor in it. Different sorts of electric motors are utilized in these energy meters. Some energy meter uses mercury motor, commutator motor, induction motor in it. The mercury motor energy meters are only used on D.C Circuits whereas the induction motor energy meters are used only on A.C Circuits and therefore the commutator motor energy meters are used on both D.C Circuits and A.C Circuits.
The energy meters used for D.C circuits provide readings within the sort of amp-hours or in watt-hours. In this mechanism of readings, the moving system revolves continuously. The speed of rotation is directly proportional to the current. The rotating system is controlled by the static magnet which is placed nearly to the moving system and produce eddy currents in some parts of the rotating system.
Induction-type Energy meters
Induction type energy meters, Single phase energy meters are most ordinarily used as A.C meters in domestic and industrial installations. These energy meters measure electric power in kilowatt-hours. These induction motor energy meters are specially designed for single-phase electric circuits. In these energy meters, brake magnets make eddy currents within the disc which revolves continuously through a fraction of adjusting.
Electrolytic Energy Meter
The Electrolytic Energy meter is an ampere-hour energy meter and is employed in just D.C circuits. Their readings are wrong when these meters are used on other voltage readings. These energy meters aren’t ready to use on A.C circuits. These instruments can be used on AC circuits by using a small rectifier unit in it.