Meter Constant For Digital Energy Meters

Does the meter say "Xnnnn" anywhere on it? Does it show a decimal point?

it depends on different make of energy meter u r using

what ratios of CT u have used for energy measurement

u r you are

analouge analogue

On the analog meters, the meter constant was usually labeled K_h. The equivalent constant on digital meters is usually labeled K_e. This has been the case on many meters I have calibrated in the past (GE, ABB, JEM/Scientific Columbus, etc.).

In the old days of spinning aluminum disks and dial indicators you needed a way of relating how many revolutions of the disk represented 1 KWH passing through the meter, that number was the meter constant. Depending upon the manufacturer and style of the meter there was often a Register Ratio and a Gear Ratio that related the revolutions of the disk to the incremental change in the motion of the register (read out dials).

This allowed utilities to use one meter style for different voltage/current combinations such as 120V/50A, 120V/100A, 240V/100A, 240V/200A, etc. simply by changing the gearing from the disk to the register. However, the actual consumption depends upon whether there are any potential or current transformers (PTs/CTs) between the meter and the incoming line. Again in the old days there was a TR (Transformer Ratio) that was usually tagged to the register or shown on the billing statement that related the kWh registered to the kWh consumed.

Modern digital meters can be programmed with the TR or not, so there is no way to tell by looking at the meter if it is direct reading or needs to be multiplied by the TR. Your billing statement is the only clue. If the meter and the bill kWh agree then the meter has been programmed for all the constants, if not then there will be a TR (which may still be called the metering constant) that gets multiplied times the reported reading to get the actual consumption.