How Electric Meters Work

Have you ever wondered how electric meters work? These meters are placed on your home or business so that the local power company can gather information pertaining to your power consumption. The information that the power company gathers is used for several different things besides how much to charge you every month. They also use the data they collect from your meter to find out what areas use the most electricity and when they use it. This is because storing electricity is very expensive and when the power company knows when power will be needed the most, they can attempt to have it on hand to reduce or eliminate power outages and black- or brown-outs.

Electromechanical Induction Meter

The electromechanical meter is by far the most common electric meter in use today. These meters are usually round in shape and have a glass cover over the face. When looking at this meter, you will see an aluminum disk that spins along with five or six gauges that can be read to acquire the data. The meter works by counting the number of turns by the aluminum disk. This disk rotates at a rate conversant to the use of the electricity.

The aluminum disk has two coils that make it spin. One coil creates a magnetic flux to read the voltage (or the electric potential energy) per unit. The other coil reads the current or the flow of energy that is produced. Using a lag coil, the field of energy is delayed by 90 degrees. This causes eddy currents in the disk, which force it to move in conjunction with the voltage and current. There is a magnet that produces an opposing force that is equal to the rate of the disk. The balances between the two opposing forces cause the disk to spin at a rate that equals the amount of electricity that is being used. The spinning disk then drives a mechanism that counts the revolutions over an amount of time.

How to Read an Electromagnetic Meter

To read your electric meter, you will look at the gauges or dials from left to right. They are labeled one through nine. The first dial spins clockwise, the second counter-clockwise, and so on. To read the numbers, write down the number that the arrow points to on the face of each dial. If any dials are between numbers, look at the one to the left of it. If that dial is on a higher number (such as eight) then the number of the dial that you are unsure of is on the higher number also.

You can use these readings from your electric meter to determine how much power you are using at any time. You may also use this to determine which appliances are using the most power in your home. Simply write down the numbers on the meter with the appliance turned on and then turn the appliance off, wait one hour and read the meter again. You would then subtract the first number from the second number to find out the difference in power consumption.