Types of Energy Meters and Their Working Principles

Energy Meter or Watt-Hour Meter is an electrical instrument that measures the amount of electrical energy used by the consumers. Utilities are one of the electrical departments, which install these instruments at every place like homes, industries, organizations, commercial buildings to charge for the electricity consumption by loads such as lights, fans, refrigerator, and other home appliances.

The basic unit of power in watts and it is measured by using a Din Rail Energy Meter. One thousand watts make one kilowatt. If one uses one kilowatt in one-hour duration, one unit of energy gets consumed. So energy meters measure the rapid voltage and currents, calculate their product and give instantaneous power. This power is integrated over a time interval, which gives the energy utilized over that time period.

Types of Energy Meters

The energy meters are classified into two basic categories, such as:

• Electromechanical Type Induction Meter

• Electronic Energy Meter

The electricity supply connection may be either single phase or three phase depending on the supply utilized by the domestic or commercial installations. Particularly in this article, we are going to study about the working principles of single-phase electromechanical induction type energy meter and also about three-phase electronic energy meter from the explanation of two basic energy meters as described below.

Single Phase Electromechanical Induction Energy Meter

It is a well-known and most common type of age-old Smart Energy Meter. It comprises a rotating aluminum disc placed on a spindle between two electromagnets. The rotation speed of the disc is proportional to the power, and this power is integrated by the use of gear trains and counter mechanisms. It is made of two silicon steel laminated electromagnets: shunt and series magnets.

What Does Surge Protector Mean?

A Voltage Protector is an electrical device that is used to protect equipment against power surges and voltage spikes while blocking voltage over a safe threshold (approximately 120 V). When a threshold is over 120V, a surge protector shorts to ground voltage or blocks the voltage. Without a surge protector, anything higher than 120V can create component issues, such as permanent damage, reduced lifespan of internal devices, burned wires and data loss. A surge protector is usually installed in communications structures, process control systems, power distribution panels or other substantial industrialized systems. Smaller versions are typically installed in electrical service entrances located office buildings and residences.

A voltage spike is a short upsurge of voltage intensity that occurs when a surge sustains longer voltage intensity. A power strip, which is sometimes mistaken for a surge protector, uses a male electrical plug outlet and may or may not have a built-in surge protector. Most power strips are clearly labeled. A common misconception is that surge protectors always protect against lightning, which can create sudden and increased electrical pressure (thousands of volts or greater). Generally, a surge protector has a slight operational delay, but an Over And Under Voltage Protector fuse can blow during a lightning surge and cut off all current.

Surge protector components and features include:

• An iron core transformer transfers alternating current (AC) power but cannot absorb sudden surges.

• A zener diode protects against common circuit spikes and is sometimes combined with a transient voltage suppression diode.

• If a circuit breaker is out or blows a fuse, a surge protector provides internal protection and protects against device and exterior surges.

• An uninterruptible power supply takes in spikes using a low pass filter and allows external power beyond the battery, which supplies uninterrupted power.

• A metal oxide varistor (MOV) is thermal fused and limits voltage three to four times that of a regular current. Parallel MOV connections expand life expectancy and increase current capacity. If exposed to many large transients or numerous small transients, MOVs can self-destruct.

What Is a Power Supply?

A power supply is an electrical device that converts the electric current that comes from a power source to the voltage value necessary for powering a load, like a motor or an electronic device.

There are two main designs for power supplies: a linear power supply and a Switching Power Supply.

• Linear: A linear power supply designs use a transformer to step down the input voltage. Then the voltage is rectified and turned into a direct current voltage, which is then filtered to improve the waveform quality. Linear power supplies use linear regulators to maintain a constant voltage at the output. These linear regulators dissipate any extra energy in the form of heat.

• Switching: A switching power supply design is a newer methodology developed to solve many of the problems associated with linear power supply design, including transformer size and voltage regulation. In switching power supply designs, the input voltage is no longer reduced; instead, it’s rectified and filtered at the input. Then the voltage goes through a chopper, which converts it into a high-frequency pulse train. Before the voltage reaches the output, it’s filtered and rectified once again.

How Does a Switching Power Supply Work?

For many years, linear AC/DC power supplies have been transforming AC power from the utility grid into DC voltage for running home appliances or lighting. The need for smaller supplies for high-power applications means linear power supplies have become relegated to specific industrial and medical uses, where they are still needed because of their low noise. But Switched-Mode Power Supply has taken over because it is smaller, more efficient, and is capable of handling high power.