An electric meter or energy meter is a device that measures the amount of electrical energy supplied to or produced by a residence, business or machine.
The most common type is a kilowatt hour meter. When used in electricity retailing, the utilities record the values measured by these meters to generate an invoice for the electricity. They may also record other variables including the time when the electricity was used.
Modern electricity meters operate 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.
Electromechanical metersThe most common type of electricity meter is the Thomson or electromechanical induction watt-hour meter, invented by Elihu Thomson in 1888.[1][2]TechnologyThe electromechanical induction meter operates by counting the revolutions of an aluminum 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.
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.
The type of meter described above is used on a single-phase AC supply. Different phase configurations use additional voltage and current coils.Reading
The aluminum 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.
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 . 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.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 test for error due to creep is called a creep test.
It is the meter that is on the side of housed to measure the amperage that the house uses. Watts = amps x volts
AnswerAn energy meter measures the energy supplied by a electricity supply utility, expressed in kilowatt hours. It does this by monitoring the supply voltage and the in-phase component of the load current. The combined magnetic flux produced by the coils that monitor these quantities drives an aluminium disc which introduces the time element.Principle- 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. 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.
no applications
just measures the energy consumesd
and not able to measure the power factor....
:-)
Errors in energy meter and methiods to eliminate errors
You need to have your power company make any needed adjustments to your meter. Any attempt by you to adjust the meter will constitute fraud, and you could go to jail.
You need to have your power company make any needed adjustments to your meter. Any attempt by you to adjust the meter will constitute fraud, and you could go to jail.
crimping error.
enery meter which reduce the man work
A three-phase meter can be used for single phase while the reverse is not the case.
Phasing, or the number of phases in an electrical system has nothing to do with the voltage. A single phase and three phase supply could have a voltage supply of any given voltage from virtually 0 to infinity. Most single phase power supplies in the US are 120/208-240 volt. Three phase power supplies are typically 120/208 to 277/480 volt.
The reverse running of a three phase meter is possible when one of the meter's two potential coils fails. This is a problem found typically on a Delta service. A three phase meter in this condition is damaged and will report lower energy use than actual.
It's unlikely you have a two-phase supply. Two-phase systems (two phases, displaced by 90 electrical degrees) are very old, and there are very few two-phase systems around. Assuming you really mean 'two phase', t's unlikely, therefore, that you can use a three-phase energy meter using its standard terminals.
Yes it would work pretty well but it might not meet its accuracy specification.
A three-phase meter can be used for single phase while the reverse is not the case.
working of single phase preventor
The reading on the 3-ph meter would equal the sum of the three separate readings on the single-phase meters. The neutral sides of the single phase meters do not need to be connected to the neutral wire as long as they are connected together.
If you do not know, and wish to stay alive, employ a qualified electrician :)
No. For three phase, you need a minimum of a two element meter.
Phasing, or the number of phases in an electrical system has nothing to do with the voltage. A single phase and three phase supply could have a voltage supply of any given voltage from virtually 0 to infinity. Most single phase power supplies in the US are 120/208-240 volt. Three phase power supplies are typically 120/208 to 277/480 volt.
with an meg ohm meter
The speed of a single phase digital meter 1600mp or kWh 50HZ can be reduced. By decreasing the voltage to reduce the speed of the single phase digital meter the motor is to decreased in speed meaning the consumer load will be decreased as well.
shading bands are used to increase the magnetic field in shunt magnet in single phase energy meter. They also used for reduce the friction error.
Two single phase meters are not needed. A three phase meter is manufactured and is used when installing a three phase electrical distribution.
A 3-phase meter measures the sum of the power in the three phases, so if power is drawn on one phase only it will still be correctly measured.
Single phase motor winding is often checked just by listening to the noise that the motor is making. An experienced person can tell if the motor is working at single phase or double phase.