Reed sensors for Tamper-proofing Electricity Meters
Electric Companies use meters calibrated to measure 1 kilo-watt-hour and also measure maximum demand, which is the peak kilo-watt drawn during the billing period. Using the collective information from total usage and maximum demand, a bill is generated. The most common electromechanical induction meters operate through electromagnetic induction by counting the revolutions of a disc which is made to rotate at a speed proportional to the power passing through the meter.
With the advent of digital electronics and the Internet, electricity companies generate readings automatically and post bills on their website, where customers login and settle their dues. In such situations, where visits from the company are rare, unscrupulous customers sometimes use methods of tampering such as attaching magnets to the outside of the meter to saturate the magnetic fields and stop the disc from spinning. To tamper proof these meters, Reed Sensors are placed near the front cover of the meter, in the vicinity of the rotating disc. These sensors are specially selected, having a low AT band so that it detects the weakest of external magnetic fields. This ensures that the tampering is detected well before the external magnet has any effect on the rotating disc, and triggering an alarm to the electricity company.
Applications are classified as Position Sensing, Pulse Counting, Electromagnetic or Relay, Temperature Sensing or Magnet Biasing types. This application is classified as follows and the link gives more information on best practices to help select the most suitable AT band and matching magnet.
The Reed Switches and Sensors used in such applications need to be robust, durable and efficient in meeting a high life expectancy. Our engineers work hard in life testing our products under various conditions, and our intention is to ensure end product durability and life. Although we wouldn’t want to restrict any of our products for use in only certain applications, the recommended products for use in this application are listed below.
R3 Miniature SMD Reed Sensor
|Omni polar, normally open (NO), 16.25 mm SMD and low-profile SMD pitch. 10 W...Continue reading|
R2 Standard size SMD Reed Sensor
|Omni polar, normally open (NO), 19.5 mm SMD and low-profile SMD pitch, 10 W...Continue reading|
MS-108 Standard Size PCB Mountable Reed Sensor
|Omni polar, normally open (NO), epoxy encapsulated, 17.7 mm PCB mountable pin pitch, capable...Continue reading|