Operates by continuously measuring the instantaneous voltage (volts) and current (amperes) and finding the product of these to give instantaneous electrical power (watts) which is then integrated against time to give energy used (joules, kilowatt-hours etc). The meters fall into two basic categories, electromechanical and electronic. Download high resolution version (700x762, 56 KB)photograph of mechanism of an electrical induction meter (kilo-watt hour meter) Image taken by me Ali@gwc. ... Download high resolution version (700x762, 56 KB)photograph of mechanism of an electrical induction meter (kilo-watt hour meter) Image taken by me Ali@gwc. ... Image File history File linksMetadata Download high resolution version (2272x1704, 837 KB) Summary Close-up photo of a mechanical electricity meter; Note how every other dial turns anticlockwise. ... Image File history File linksMetadata Download high resolution version (2272x1704, 837 KB) Summary Close-up photo of a mechanical electricity meter; Note how every other dial turns anticlockwise. ... Download high resolution version (450x640, 47 KB)Three-phase electromechanical induction electricity meter, metering 100A 230/400V supply. ... Download high resolution version (450x640, 47 KB)Three-phase electromechanical induction electricity meter, metering 100A 230/400V supply. ... International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ... Josephson junction array chip developed by NIST as a standard volt. ... This box: Electric current is the flow (movement) of electric charge. ... For other uses, see Ampere (disambiguation). ... For delivered electrical power, see Electrical power industry. ... For other uses, see Watt (disambiguation). ... This article is about the concept of integrals in calculus. ... The joule (symbol J, also called newton metre, or coulomb volt) is the SI unit of energy and work. ...
Electromechanical meters
The most common type of electricity meter is the Thomson or electromechanical induction watt-hour meter, invented by Elihu Thomson in 1888.[1][2] In engineering, electromechanics combines electromagnetism and mechanics. ... Look up induction in Wiktionary, the free dictionary. ... Elihu Thomson (March 29, 1853 - March 13, 1937) was an engineer who was instrumental in the founding of major electrical companies in the United States, Britain and France. ...
Technology
The electromechanical induction meter operates by counting the revolutions of an aluminium disc which is made to rotate at a speed proportional to the power. The number of revolutions is thus proportional to the energy usage. It consumes a small amount of power, typically around 2 watts. For magnetic induction, see Magnetic field. ... Aluminum redirects here. ...
The metallic disc is acted upon by two coils. One coil is connected in such a way that it produces a magnetic flux in proportion to the voltage and the other produces a magnetic flux in proportion to the current. The field of the voltage coil is delayed by 90 degrees using a lag coil. [1]This produces eddy currents in the disc and the effect is such that a force is exerted on the disc in proportion to the product of the instantaneous current and voltage. A permanent magnet exerts an opposing force proportional to the speed of rotation of the disc - this acts as a brake which causes the disc to stop spinning when power stops being drawn rather than allowing it to spin faster and faster. This causes the disc to rotate at a speed proportional to the power being used. An induction coil or spark coil (archaically known as a Ruhmkorff coil) is a type of disruptive discharge coil. ... Magnetic flux, represented by the Greek letter Φ (phi), is a measure of quantity of magnetism, taking account of the strength and the extent of a magnetic field. ... International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ... This box: Electric current is the flow (movement) of electric charge. ... As the circular plate moves down through a small region of constant magnetic field directed into the page, eddy currents are induced in the plate. ... For other uses, see Force (disambiguation). ... Magnetic lines of force of a bar magnet shown by iron filings on paper A magnet is an object that has a magnetic field. ... Angular velocity describes the speed of rotation and the orientation of the instantaneous axis about which the rotation occurs. ... This article is about the vehicle component. ... This article is about proportionality, the mathematical relation. ...
The type of meter described above is used on a single-phase AC supply. Different phase configurations use additional voltage and current coils. In electrical engineering, single-phase electric power refers to the distribution of electric power using a system in which all the voltages of the supply vary in unison. ... City lights viewed in a motion blurred exposure. ... A polyphase system is a means of distributing alternating current electrical power. ...
Reading
The aluminium disc is supported by a spindle which has a worm gear which drives the register. The register is a series of dials which record the amount of energy used. The dials may be of the cyclometer type, an odometer-like display that is easy to read where for each dial a single digit is shown through a window in the face of the meter, or of the pointer type where a pointer indicates each digit. It should be noted that with the dial pointer type, adjacent pointers generally rotate in opposite directions due to the gearing mechanism. For other uses, see Gear (disambiguation). ... In mathematics and computer science, a numerical digit is a symbol, e. ...
The amount of energy represented by one revolution of the disc is denoted by the symbol Kh which is given in units of watt-hours per revolution. The value 7.2 is commonly seen. Using the value of Kh, one can determine their power consumption at any given time by timing the disc with a stopwatch. If the time in seconds taken by the disc to complete one revolution is t, then the power in watts is P = 3600 × Kh / t. For example, if Kh = 7.2, as above, and one revolution took place in 14.4 seconds, the power is 1800 watts. This method can be used to determine the power consumption of household devices by switching them on one by one.
Most domestic electricity meters must be read manually, whether by a representative of the power company or by the customer. Where the customer reads the meter, the reading may be supplied to the power company by telephone, post or over the internet. The electricity company will normally require a visit by a company representative at least annually in order to verify customer-supplied readings and to make a basic safety check of the meter. Electricity retailing is the final process in the delivery of electricity from generation to the consumer. ... For other uses, see Telephone (disambiguation). ... For other uses, see Mail (disambiguation). ...
Accuracy
In an induction type meter, creep is a phenomenon that can adversely affect accuracy, that occurs when the meter disc rotates continuously with potential applied and the load terminals open circuited. A creep test is when the meter is tested for the error due to creep.
No comments:
Post a Comment