An electrical meter is also called energy meter, electric meter, and electricity meter as per each device’s working principle and function. It is an integrated instrument that measures the electric energy quantity supplied to an electric circuit in a particular period of time. The consumed energy is displayed in KWH (kilowatts/hour).
Applications of an Electrical Meter
Electrical meters are generally used in domestic, commercial, and industrial areas to measure the amount of electric power that is consumed by these units. Electrical meters are utilized in homes to measure the energy consumed by users. In industries, this device is used to control the power of different machines. Some advanced industrial applications of smart electrical metering systems are:
- Managing grid frequency
- Event correlation for network and substation level
- Controlling facility computers and terminal units, including SCADA
- Monitoring Lightning strikes
- Planned load shedding
- Transiting wave fault location
- Synchrophasor measurement
- TDM communications networks
Types of Electrical Meters
Electrical meters are of two main types which are:
- Electrolytic electrical meter
- Electric energy meter
Electrolytic Electric Meters
An electrolytic energy meter is an ampere-hour meter that can be used only in D.C circuits as it gives incorrect readings when utilized on A.C. circuits. To be suitable for A.C. circuits, it needs to be fitted with a rectifier unit. These electrical meters function as per Faraday’s law of electrolysis and are accurate in measuring small loads, making it cheap and simple. Note that friction errors and stray magnetic fields do not impact these meters.
Electric Motor Electrical Meters
These meters get their name from the small electric motor they contain. The electric motors are of different types, including induction, commutator, and mercury motors. The induction motor type is utilized only on A.C. circuits, while the mercury motor type is suitable only for D.C. circuits. The commutator motor type can be leveraged on both D.C. and A.C. circuits.
Some Other Types of Electrical Meters are:
Ampere-hour Mercury Motor Electrical Meter
This device is built as a copper disc placed on a spindle. Further, the disc rotates between two permanent magnets with the space between them containing mercury. One magnet is utilized to break the disc rotation.
Watt-hour Mercury Motor Electrical Meter
In this type, the permanent magnet M2 in an ampere-hour device is replaced by a wound magnet and linked to the supply. This electromagnet’s exciting current is in proportion to the voltage. Further, the disc is cut with radial slots.
Commutator Motor Electrical Meter
These meters are also termed watt-hour electrical meters as well as Elihu Thomson meters after their working principle. They are made of ironless motors that contain a commutator and wound winding armature.
Induction Type Single-Phase Electrical Meters
These devices are commonly utilized as A.C. meters in industrial and domestic installations. They measure electricity in kilowatt-hours and are built for one-phase electricity circuits. In these meters, brake magnets create eddy currents in the disc that continuously revolves through a changing fraction.
Single-Phase Electrical Meter
A single-phase electrical meter has two electromagnets named M1 and M2. The M1 magnet is excited by line current and is termed a series magnet. This magnet creates alternating flux φ1, which is proportional to the phase with the line current.
The second magnet, M2, is termed as a shunt magnet, and it is linked to the supply line. Its current is proportional to the supply voltage, and it creates a lagging flux φ2. Most of this flux is not helpful, and only a small amount of it is useful which passes via the disc D.
It is recommended that you first consult with a certified electrical professional to understand your requirements better and get expert recommendations for selecting the best electrical meter. Trained professionals can also help you with the installation of electrical meters!