Energy Meter: Basics and Connection in a Circuit

Friends,
In Connecting Voltmeter, Ammeter and Watt Meter in a circuit we have discussed how to connect Ammeter, Voltmeter and Watt meter in a circuit. Energy meter is one of the very common instrument that is used frequently used in every house or industry that is connected to the power grid and consumes electrical energy.

Energy Meter : Definition

Energy Meter, electrical energy meter or energy meter is an electrical device which is used to measure the consumption of electrical energy in a circuit. In short an energy meter records the energy consumed or energy it has passed to the circuit, building or institute to which it is connected. An energy meter measures energy in KWh (kilo watt hour) which is normally called 1 unit of electrical energy. 1 kWh is equal to 3.6 x 10⁶ Joules.

Energy Meter : Types

There are a variety of energy meters available in the market or already installed at various locations ranging from 120 years old bulky induction type electromechanical energy meter to latest prepaid electronic based energy meter.
Basically two types of energy meter are very common in India and abroad :

1. Electromechanical Energy Meter
2. Electronic Energy Meter

Electromechanical Energy Meter

This meter works on the principal of electromagnetic induction. It produces two field one proportional to current passing and other proportional to potential different across the terminals. These fields produces two fluxes around the aluminium disc placed between these electromagnets. These fluxes produces a torque and makes the disc move/rotate and these rotations are counted to give energy consumption.

Electronic Energy Meter

These are latest and more accurate energy meters. These uses electronic circuit to measure voltage and current in a circuit and then compare this power with the inbuilt timer to give energy consumption.

Connection of Energy Meter

Two types of energy meter are installed in domestic and industrial areas. 1 phase or 1Φ in domestic area and 3 phase or 3Φ in industrial area. These meters have almost similar connection arrangement as shown in the figure below:

Here one side is supply side and other is consumer side. Three wires are connected to each side viz. P(Phase Wire), N(Neutral Wire) and E(Earth Wire). Earth wire is for safety purpose. Phase wire provide current and Phase and Neutral together provide the potential difference.
I hope this article was helpful for you.