Ground Enhancement Materials - An Overview

Ground enhancement materials are materials which are used to enclosing the grounding object such as a rod, plate, etc to increase the ground resistance.  The ground resistance in an area depends on the soil conditions.  Areas which have rocky ground, sandy soil or frozen ground will have high ground resistance.  

In order to reduce the ground resistance, ground enhancement materials may need to be used.  These materials have high conductivity.  They increase the ground resistance by increasing the surface area in contact with the ground.  

Common ground enhancement materials are bentonite clay. petroleum coke powder, earthing cement (marconite)  and salts such as sodium chloride, copper sulphate and magnesium sulphate.

Posted by: Electrotechnik

What is ionized air? What are its uses ?

Ionised air which has been charged either positively on negatively.  The positive charge is given by removing an electron from the oxygen atoms.  When an electron is added to the oxygen atom, the atom acquires a negative charge.    Ionized air is produced by making air to pass through an electric field.

Most ionized air is negatively charged.  This helps the air to attract dust and other floating particles such as germs and pathogens.  For this reason, ionized air is used in hospitals as a disinfectant.  Thus air ionization has emerged as an effective air cleaning technology.

You would have noticed how the sky appears clearer after a rain.  This is because the air is charged after a rain due to the electric effects of the rainfall.  This attracts the dust particles giving a clearer appearance.

Ionized air also carries an inherent risk.  During the process of ionization, ozone (O3) is also produced.  Ozone can be toxic to humans at high levels.  Hence, ionized air used in medical applications should have low ozone generation.  

Ionized air is also used in electronic to prevent accumulation of static charge.  They are also used in industries to prevent charge accumulation in fabrics, paper, plastic, etc.  

Posted by: Electrotechnik

How is Mesh Protection for lightning done ?

The mesh method of lightning protection is a method of protecting buildings.  The mesh method involves enclosing the building inside a metallic cage.  The cage is also known as a faraday's cage.  The mesh method
works by ensuring that the lightning which strikes the building always flows on the outside through the metal cage.  Hence, no damage is done to the building.

The mesh method cannot be used in circular surfaces.  The number and distance between the conductors in the mesh method needs to be calculated. 

Posted by: Electrotechnik

Electrostatic Control and Humidity

Electrostatic charge builds up when there is rubbing between different materials.  This charge is undesirable in many cases.  Electrostatic charge accumulation can result in sparking which has a risk of fire.  It can also result in jamming of papers in printers.  In the textile industry, the fabric which passes through the machines can get stuck due to charge accumulation.  Charge accumulation also results in dust accumulation on surfaces which is an area of concern in the painting industry.  Charge accumulation and electrostatic discharge can destroy electronic components.

Hence, control of electrostatic charge accumulation is vital in many industries.  Humidity plays an important role in electrostatic control.  When the air is humid, a thin layer of moisture appears on the surface of the material.  This increases the surface conductivity.  This ensures that the charge which accumulates on the surface is dissipated through the conductive layer of moisture.

When dry air blows over insulating materials, it can itself cause charge build up.  

A humidity of 40 to 60 percent can help reduce charge build up.  Relative humidity lower than 30% can result in high levels of charge.  However, if the relative humidity is too high it can result in corrosion.  Hence, any humidity control system should be closely monitored.  

Posted by: Electrotechnik