How does your electricity meter work?
07 January 2002, 10:32 PM
#1
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AHA, well I remember when my daddy had this meter put in when I was 13years old - 60 years ago!!! and its amazing how slow it goes when I turn the electro-magnets on!! 
Never had an electric bill for over £25 a quarter yet - and all my heating is Bar Heating!! result!!
Pete
[Edited by pslewis - 7/1/2002 10:33:04 PM]
Never had an electric bill for over £25 a quarter yet - and all my heating is Bar Heating!! result!!
Pete
[Edited by pslewis - 7/1/2002 10:33:04 PM]
01 July 2002, 05:36 PM
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Emm, I've never been able to fathom that one out either, got something to do with the phase of the ac I think.
What you thinking of taking it apart and trying to slow that damn spinning wheel down
What you thinking of taking it apart and trying to slow that damn spinning wheel down
01 July 2002, 05:43 PM
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Nope, not taking it apart......just interested!!
Must have a CT to measure the current, but not sure how it gets the power factor so that it can work out the kW (real power) from the kVA.
Must have a CT to measure the current, but not sure how it gets the power factor so that it can work out the kW (real power) from the kVA.
01 July 2002, 06:23 PM
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What is a kilowatt-hour?
Simply put, for every 10 hours a 100-watt bulb burns, one kilowatt-hour of electricity is used.
Meters operate with clock-like accuracy because they are sealed to keep the interior free of dust and other contaminants. Also, the use of a magnetic-suspension system all but eliminates friction inside the meter.
Just like a small motor
Your meter is basically a small induction motor run by magnetic forces that are created by electricity in a set of coils. The voltage coil is a winding or wire connected to the outside power supply lines. The current coil is a winding of wire connected to your household wiring. When current passes through these coils, the disk is forced to turn at a speed that is exactly proportional to the number of watts (amps x volts) of electrical power you are using.
The amount of electricity you use determines the speed at which the disk moves. The more electricity you use, the faster it turns. Each revolution measures a precise amount of electric energy called watt-hours, usually 7.2 watt-hours. This measurement is transferred from the disk through a series of gears to the pointers on the dials.
Today, most meters are nameplate-rated 30 amperes at 240 volts – or, 7,200 watts of power. At this power, the disk rotates 1,000 revolutions per hour. As the disk spins 1,000 times, the gears attached to its shaft move pointers on the meter’s dials forward 7.2 kilowatt-hours.
Simply put, for every 10 hours a 100-watt bulb burns, one kilowatt-hour of electricity is used.
Meters operate with clock-like accuracy because they are sealed to keep the interior free of dust and other contaminants. Also, the use of a magnetic-suspension system all but eliminates friction inside the meter.
Just like a small motor
Your meter is basically a small induction motor run by magnetic forces that are created by electricity in a set of coils. The voltage coil is a winding or wire connected to the outside power supply lines. The current coil is a winding of wire connected to your household wiring. When current passes through these coils, the disk is forced to turn at a speed that is exactly proportional to the number of watts (amps x volts) of electrical power you are using.
The amount of electricity you use determines the speed at which the disk moves. The more electricity you use, the faster it turns. Each revolution measures a precise amount of electric energy called watt-hours, usually 7.2 watt-hours. This measurement is transferred from the disk through a series of gears to the pointers on the dials.
Today, most meters are nameplate-rated 30 amperes at 240 volts – or, 7,200 watts of power. At this power, the disk rotates 1,000 revolutions per hour. As the disk spins 1,000 times, the gears attached to its shaft move pointers on the meter’s dials forward 7.2 kilowatt-hours.
01 July 2002, 08:50 PM
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Modern meters, perhaps not in this country yet, use semiconductors to make power measurements. One such device is the CS5460 from Cirrus Logic http://www.crystal.com/design/produc...tail.cfm?d=142. (I've just done a power measurement system using this chip.)
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02 July 2002, 04:16 PM
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Pete - I fould it was cheaper to get it disconnected and the wire all the cables into the supply in the neighbours shed. At least that way someone is still paying for it
(I tried the same with the phone, but he got suspicious about the phone cable running across the living room floor and acroos the garden, so I had to remove it)
(I tried the same with the phone, but he got suspicious about the phone cable running across the living room floor and acroos the garden, so I had to remove it)
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