Construction of a domestic electricity meter with voice announcement
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An electrical meter, an electric meter, an electric meter or an energy meter is a device that measures the amount of electrical energy consumed by a residence, business or electrical device. Electric utilities use electric meters installed at customers' facilities to measure the electrical energy delivered to their customers for billing purposes. Usually calibrated in billing units, the most common is kilowatt hour [kWh]. Usually, each billing period is read.
When energy savings are desired during certain periods, some meters can measure demand, the maximum use of energy in some interval. The "time of day" measurement allows to change the electric rates during a day, to record the use during the periods of high cost peak and the periods of peak, of less cost. In addition, in some areas the meters have relays for load shedding to respond to demand during peak load periods.
Principle of operation of the energy meter
The operation of monophasic induction type energy meters is based on two main fundamentals:
1. Aluminum disk rotation.
2. Disposition of the count and display of the amount of energy consumed.
Rotation of an aluminum disc
The rotation of the metal disk is operated by two coils. Both coils are arranged in such a way that one coil produces a magnetic field in proportion to the voltage and the other coil creates a magnetic field proportional to the current. The field produced by the voltage coil is delayed by 90 ° so that a eddy current is induced in the disk. The force exerted on the disk by the two fields is proportional to the product of the immediate current and the voltage in the coils.
As a result, a lightweight aluminum disc rotates in an air gap. But there is a need to stop a disc when there is no power supply. A permanent magnet acts as a brake that opposes the rotation of the disc and balances the speed of rotation with respect to energy consumption.
Willingness to count and visualize the energy consumed
In this system, the floating disk rotation has been counted and then displayed in the meter window. The aluminum disc is connected to a spindle having a gear. This gear drives the register and the disc revolution has been counted and shown in the register which has series of dials and each dial represents a single digit. There is a small display on the front of the meter that shows the reading of energy consumed with the help of dials. There is a copper shading ring on the central member of the bypass magnet. To make the phase angle between the flux produced by the bypass magnet and the supply voltage about 900, small adjustments to the ring location are required.