Friday, October 30, 2009

What are Lightning Arresters?


Lightning arresters or surge diverters are used to protect the earth screen and ground wires in an electrical system against direct lightning strokes. They conduct the high voltage surges to the ground without getting affected to the system. The lightning arrestor provides a cone of protection which has a ground radius approximately equal to its height above the ground.

The surge diverters consist of a spark gap in series with a nonlinear resistor. The function of non linear resistor is very important. As the gap sparks over, due to the over voltage, the arc would get short circuited and may cause power flow current in the arrester. Since the characteristic of the resistor is to offer high resistance to high voltage, it prevents the effect of a short circuit. After the surge is over, the resistor offers high resistance to make the gap non-conducting.

One end of the arrestor would be connected to the terminal of the equipment to be protected and other end would be grounded. The length of the spark gap is set in such a way that normal line voltage is enough to cause an arc across the gap but high voltage would break down the air insulation and form an arc.

Different types of surge diverters are available depending on the purpose. Some of them are Rod gap arrester, Horn gap arresters, Multigap arresters, Expulsion type lightning arrester and valve gap arrester. Each of them has variety of range of operating conditions.

Wednesday, October 28, 2009

What are Acoustic Couplers?


The term acoustic means sound. This is a device used in telecommunication field for coupling electrical signals by acoustical means. Its main working is related to our telephone. Acoustic coupler is a terminal and interface device to link data terminals and radio sets with telephone. Acoustic couplers are used to transmit data over telephone lines using modems. This is a device onto which telephone handset is placed to connect computer to the network, a modem will be also there. Modems that do not use acoustic coupler can some times be called as Direct Connected Modems

The link between the terminals and telephones can be achieved by means of acoustic signals rather than through electrical connections. In 1956 acoustic couplers came into use in our telephone industry till then this industry was a closed system wholly controlled and owned by Bell systems.

At first acoustic couplers were sensitive to external disturbances and noises. Direct electrical connections to telephone networks were made legal in early times. But rapidly preference got secured to the modem connecting method and hence acoustic couplers are used widespread. At times acoustic couplers are no longer used since now a days, telephones can be directly connected to modem instead of connecting to modular telephone connectors. Better connections can be established by avoiding unwanted breakage in signals. Still acoustic coupler modems can be useful in some situations like, in a hotel room where telephone cable is anchored in the walls.


What is a VARISTOR?

The name varistor came from variable resistor. Varistor is a pure electronic component used to protect circuits from transient over voltages making the circuit triggered. The function of a varistor is to provide increased current when voltage becomes excessively high. Varistor is also known as Voltage Dependent Resistor (VDR) since it depends on voltage.

The most common type we are dealing with now days is Metal Oxide Varistor (MOV). It is just like a Unijunction Transistor, since it allows current flow only in one direction. It contains mass of ceramic grains enclosed between two metal plates. The boundary between and its neighbour forms a diode junction. So when a small voltage is applied across the electrodes, only a small current passes due to the reverse break down at the junctions. Similarly when a large voltage is applied, due to thermionic emission large current passes through the junction. This behavior results in nonlinear current voltage characteristic.

Varistor can absorb surge in some ways but to some to extent. A typical surge protector power strip can be made using MOV’s. A varistor provides no equipment protection from inrush surge current. A varistor doesn’t control such events. Varistors have many applications on different electronic circuits. It can replace ordinary resistor in almost all functions, basically it can vary its resistance. So using varistors we can control voltage and current to the circuit. Thus we can protect the circuit from internal damage and severe short circuits.

Monday, October 26, 2009



SCADA is the acronym of Supervisory Control And Data Acquisition. It is used in the fields of data acquisition and monitoring in industries. SCADA is a pure software package and not having any hardware components. It is the monitoring section of a process and the decision making section. It controls all the process taken while doing a particular task.

Normally we use couplet of software, e.g. SCADA- PLC couplet. Here SCADA acts as master and PLC acts as slave. SCADA gives instructions and PLC obeys as per the order. In short control is safe in SCADA hands. It’s more convenient if we use the couplets even if SCADA alone can do all the operations alone.

SCADA operations are categorized under three below explaining sections. Such as- industrial, infrastructure and facility based processes. Industrial process includes manufacturing, production, power generation etc. Infrastructure based process means water treatment, waste water collection, refining etc. Facility process includes building, airport and all public sector processes.

SCADA mainly consists of five subsystems. Each is assigned to perform a particular task. The five subsystems are:

+ HMI or Human Machine Interface- This is an apparatus used to supply data to the human operator and through this he could able to monitor and control
+ A supervisory computer system- This is used to acquire data and to send commands to the process.
+ RTU or Remote Terminal Unit- These are connected to sensors to do a process, Converts sensor signals to digital data and sends this data to the supervisory system.
+ PLC or Programmable Logic Controller- used as field devices in a process, since they are economical, flexible, versatile and much configurable than general purpose RTU’s.
+ Communication- Many modes of communication are available. Communication connects supervisory systems to RTU’s.

Three generation SCADA software is available. They are First generation or Monolithic, Second generation or distributed, Third generation or Integrated. Now third generation is in use.

SCADA has applications on energy management system, multi tasking, automation, industrial control systems, data exchange, pipeline transport, graphical design etc. SCADA made almost all sections under its control tactically. Mainly we use this software in automation purposes. This software is freely available and another advantage is no programming is needed. So even a person who is not good in programming can handle SCADA well and efficiently.

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Thursday, October 22, 2009

What is a neural network?


The term neural network refers to be a club of biological neurons. But now this term is referred as artificial neural network which is composed of artificial neurons. So first of a comparison is needed between both the terms.

Biological neural network (BNN) is composed of natural and is connected in central nervous system or peripheral nervous system. They are destined to perform specific functions as ordained. Artificial neural network are fabricated with a group of artificial neurons. The name is so given because we know a neuron is the basic functional unit of our body which is capable of doing specific functions. These artificial ones are used to solve artificial intelligence problems. The artificial neural network (ANN) focuses on the detailed coverage of two types.

In BNN a single neuron is connected to other neurons and finally forms an extensive connection. These connections are called synapses and are connected with axons to dendrites. As such neural networks are extremely complex. Scientists need to melt the properties of BNN artificially in different areas. They ended up in the formation of ANN. The ANN concentrated in the solving of particular assigned tasks. It is successfully applied to speech recognition, face recognition, image analysis, adaptive control, to construct robots etc. Mostly now they are employed in the fields of statistical estimation, optimization and control theory. All neural networks take numeric input and numeric output.

The concept of neural networks emerged in the late 18th century. In the early 1950’s Friedrich Hayek was the one to posit this idea to the world.

The utility of ANN lies in the fact that it can be used to observe variety of functions. It can be used to determine the significance of seating arrangement in a class room. In real life it deals with function approximation, time prediction, blind signal production, data processing etc. Neural network software is used to research, stimulate, develop and apply ANN and BNN. Neural networks, with their remarkable ability to derive meaning from complicated or imprecise data, can be used to extract patterns and detect trends that are too complex to be noticed by either humans or other computer techniques. A neural network is not something that can be categorized in a single feature. It’s a day by growing branch of science. In all the ways above said neural network is a typical notable area that can produce drastic changes in technologies.



Tether means rope or chain used to fasten animals. In the case of space this tether finds application for connecting two space crafts. So tether is a term which needs key relevance that finds application even in space field. Physically a tether is a long flexible cable that connects two masses. When the cable is electrically conductive it is called as electro dynamic tether.

In the early 20th century Giuseppe Colombo came up with an idea of connecting two space crafts by means of some flexible cables. It also needed to be electrically conductive. So as a step forward to this idea NASA launched a shuttle to deploy a satellite on a tether to study the electromagnetic effects of a conducting tether as it passes through Earth’s magnetic fields ad a current was produced in the tether as it passes earth’s magnetic field, acting as an electric generator. This was the actual origin of electro dynamic tether.

There are mainly three types of electro dynamic tether employed systems available depending on the advantages.

1. Electro dynamic tether systems- In this type two heavy masses are separated by means a long flexible extensive electrically conductive cable. This can perform various functions in space craft.
2. In low earth orbit tether can provide electrical power and positioning capability for satellites and space crafts.
3. In the case of long term mission tethers could drastically reduce the amount of fuel needed.

Now tethers are made of electrically conducting materials like aluminium or copper. This provides additional advantages to the tethers. An electro dynamic tether is a device use to convert orbital energy to electrical energy and it works on the principle of electro magnetic induction. This can be used for power generation. Tethers found applications in orbit raising, lowering and debris removal. Another application of tether is artificial gravity inside space crafts.



It is the method normally called home networking through which we are capable of interconnecting computers. This networking uses excited AC wire and power outlets to transmit the desired data to homes and different offices. Powerline networking allows sharing web access, printers, PC drives with all the existing wires, that means no new wires are needed to interconnect. Power line is one of the efficient methods for interconnecting computers. It uses electrical wiring in our house to create a network.

The main and key advantage of powerline networking is the PCs need not be put near the phone outlets instead the devices are connected through electrical output. We can’t start networking just by plugging in. Power line networking is based on Alliance home plug 1.o standard. With this type of networking we can interlink all the devices in our home without interrupting the working of each device.

As said earlier no extra wire is need for this networking. It uses standard plug or outlet to interlink and hence it is possible to access any where at home. It is easy to connect with Ethernet. Ethernet is a standard protocol for transferring data to and fro. Another notable feature is this type of networking provides maximum bandwidth and variable frequency band. This is the cheapest method for connecting different devices locating in various rooms.

IN this type of networking electrical power is transmitted over high voltage lines and distributed in low voltage lines. Proprietary specifications for power line home networking have been developed by a number of different companies within the framework. Power line communication modems are available for the data transfer. So lets conclude power line networking as one of the efficient and fabulous methods to interconnect computers.

What are Electrical Generators?


It is a device that converts mechanical energy into electrical energy. The source of mechanical energy may be a reciprocating pump or turbine. Essentially an electrical generator consists of two parts-magnetic field and conductors.

The energy conversion is based on the principle of production of dynamically induced e.m.f. This dynamically induced e.m.f is produced under Faraday’s laws of Electromagnetic Induction. The e.m.f causes current flow if the circuit is closed. A generator forces electric charge to move to an external circuit, but it doesn’t produce any charge. The charge is present in the windings of wire.

Dynamo was the first electrical generator capable of supplying power to the industry. It uses electromagnetic principles for the conversion of mechanical power in electric current

As described in electrical terms and mechanical terms generator consists of two parts

1) Mechanical-Rotor and Stator

Rotor is the rotating part of motor, dynamo, alternator and generator and a Stator is the stationary part of motor, dynamo, alternator and generator.

2) Electrical-Armature and Field

Armature is the power producing component of motor, dynamo, alternator and generator and Field is the magnetic field component of motor, dynamo, alternator and generator.

Generator uses field coils that require a current flow to be present in the field coils. (Equivalent circuit). Different types of generators now in use are vehicle mount, engine generators, human powered electrical generators etc.

As described above an electrical generator converts mechanical energy into electrical energy. It is a most common which we use frequently. This plays such a major role in electricity production.

What are Sensors?


A sensor is a device that measures a physical quantity and coverts it into a signal that can be identified by an instrument. Sensors have variety of uses in almost all instruments that we come across in our everyday life. It has innumerable applications in cars, machines, elevators, aerospace, medicine, manufacturing etc. Sensors are to be designed even to measure minute readings. If its size is maintained to be small, it has various advantages. Technologically it adds variety of applications.

All sensors need to be calibrated against known standards. Resolution of a sensor is used to measure even the least variations in the measurements and displays digitally. Sensors sensitivity is another point to be noted. It indicates how much the sensors output changes when the measured quantity changes. Sensors can be used with verniar interfaces.

A good sensor must obey certain rules. They are listed under. It should be sensitive to measured property and insensitive to others, it should not influence the measured property. It should be designed so that must be linear in nature. An ideal sensor means, the output signal should be directly proportional to the measured quantity. The ideal sensor wouldn’t possess all these characters and its sensitivity will be much low

Different types of sensors are acoustic, sound, vibration, automotive, transportation, chemical etc. Sensors are small devices that can be used with large equipments with definite functions. It founds innumerable applications in all the fields of science and technology. So let’s conclude a sensor as a small magic device that can be encapsulated in different equipments for various different functions.

Mechatronics Engineering

what is mechatronics?

A formal definition of mechatronics is “the synergic integration of mechanics, mechanical engineering, electronics, computer technology and IT to produce enhanced products and systems.

Mechatronics is a vast subject which has deep roots in the fields of mechanical, electronic, computer and control engineering. Mechatronics is exceptionally useful in design engineering to create new products. Actually it is a combination of mechanics, computing, controlling etc. This combination made possible the invention of more versatile systems.

A robot is the typical example for a mechatronic system. It includes all the aspects of above said subjects. The collaboration of mechatronic molecules gives rise to new different formats of designs. Mechatronic is such an advanced field of technology which makes possible new creations with the help of almost all the major branches in technical field. Hybrid systems important to mechatronics include production drives, synergy drives, planetary exploration rovers, automotive subsystems, auto focus cameras, hard drives and CD players.

It has applications on automation and robotics, servo mechanics, sensing and control systems, automotive engineering, biomedical engineering, computer aided design, manufacturing systems etc. So this topic is much relevant to discuss about.

Monday, October 12, 2009



Electrical equipment is an appliance powered by electricity. This includes an enclosure, several electrical components, power switch etc. A machine which is the part of an electrical distribution system can be put under the category of electrical equipment. The components in this include switch board, distribution board, circuit breakers, energy meters, transformers etc

Let’s have a look at some significant electrical equipment. Electrical switch board is a major appliance. It directs electricity from one form to another. These switch boards contain large number of panels and each of it contains switches to redirect electricity. Actually the control of electricity to this switch board is carried out by electrical generators. As the power law defines the amount of power entering and leaving the switch must be equal. So generators make this stable. While going to the technical side of switch boards, it contains bus bars inside the case to isolate the switch board from the connections before it gets opened.

Distribution board is key electrical equipment. The main function of a distribution board is to divide the electric power feed into subsidiary circuits. It provides a safety breaker and fuse for each circuit in a common enclosure and hence the distribution board is sometimes called as power breaker.

An unavoidable part in electrical equipment section is circuit breakers. Basically it is an electric switch. It is designed to protect a device from over current or short circuit. It detects the fault if any and stops the flow of current to it. It incorporates manual as well as automatic control for switching operations. The latter control employs relays and operates only under fault conditions.

Its known to every one, transformer holds the top slot in the priority list. It’s a static piece of apparatus by means of which electric power from one circuit is transformed into electrical power of the same frequency in another circuit. It can raise and lower the voltage according to the need with the increase or decrease in current. The physical basis of a transformer is mutual induction and it works under the principle of Faraday’s laws of electromagnetic induction.

The above explained are some of the main electrical equipments which hold the key place in this section.

Saturday, October 10, 2009



It is commonly known as Electrical & Electronics engineering. Electrical engineering has as much relevance as electricity has in our life. So it is considered as one of the major and basic branches in engineering field. We can’t even think of an earth with out electricity.

At first this branch dealt with electricity, electronics and electromagnetism, now power electronics, power systems, digital signal processing, control systems are all handled by an electrical engineer. The major advancement in this field was emerged by late 19th centaury. By 17th centaury the work on electricity got started. It includes the famous works done by George Ohm on the relationship between current and potential difference, Michael Faraday’s Electromagnetic induction, James Clerk Maxwell’s theory on electricity and electromagnetism. These all made the advancement of an electric era so fast.

Major and noticeable inventions in this field are Cathode Ray Oscilloscope by Karl Ferdinand Baum, Diode by John Fleming, Triode by Robert Von Lieben and Lee Deforest, Albert Hull’s Magnetron which eventually lead to the development of Microwave oven by Percy Spencer. These inventions made our life as wonderful as we wish. We know how well these all take parts in our life.

In the field of education, an electrical engineer covers Maths, Physics, computer science, specific topics in electrical engineering. They should have detailed knowledge in Electrical machines, signal processing, power systems, power electronics, and control systems

An electrical engineer has to work in the development of wide range of technologies. They use to design, test and supervise all electric systems. They are destined to work in electric power stations, telecommunication systems, and satellite communications, in the fields of power generation, transmission and distribution. It includes work on transformers, motors, alternators, generators etc.

Electrical engineer has a key role in the field of space flight. Control system is a major topic in electrical engineering; this plays an exceptionally strong role in space flight. Electronics is the sub discipline of electrical branch. It involves the testing of electric circuits, properties of resistors, capacitors, diodes etc. It deals with the study of radar, commercial circuits, microprocessors and its applications on different fields.

Digital signal processing is an unavoidable section in electrical engineering. It deals with the analysis and manipulation of signals. Another markable feature is in the field of computer technology. This involves the designing of computer and computer systems.
In short, in every walk of our life we can feel the importance of electricity and hence electrical engineering.

Friday, October 9, 2009



To protect all while working under electric apparatus from hazardous conditions some rules are to be strictly followed. They are made and proposed for the safety of users. These rules are listed under several sections.

Make sure that the equipment used is safe and check its working conditions properly. If the equipment is watered by some means, do avoid contact with it. Use the appliance only for the purpose for which it is made. Before using the device, check whether it has passed the entire requirement prescribed. Avoid direct contact from fuses. The equipments that are made to use in wet conditions may only used in that condition, ensure it. Before using identify its working and disconnecting methods. Equipments with out the mark of manufacturer can’t be used. Maintenances should be done in a proper way. The cases, cables, fuses all should be fixed as prescribed. Another important thing is the equipment should be perfectly grounded and is over current protected. Several different rules are to be used in different working conditions. The devices are to be classified under type, voltage, power rating and several other factors. Replace the fuse only after rectified the mistake of the blown fuse. Avoid using wires with poor insulation. Don’t touch the circuit with fingers. Proper safety measures are to be followed in each case.

Thursday, October 8, 2009



We can’t even think of a day with out electricity. It has such relevance in our every day life. We know in earlier periods how miserable were the days with out electricity. It’s an extremely powerful force and if it’s not used properly and if proper safety measures are not taken, electricity would become deadly harmful. So the topic about safety measure is such a way important. Taking proper safety measures will always keep the harm away

It’s important to take apt measures against accidents while working indoor and outdoor. Public utility commission of Ohio offers several tips for keeping safety under all working conditions.

To ensure indoor safety we must make sure that no electric cords or wires are frayed or cracked. If any, remove or replace it in no time. Over loading is another important cause for accidents because it’s really harmful to take large number of appliances from a single outlet, it’s to be avoided. Ensure that electric plugs are fitted properly. While unplugging always pull the plug and not the cord because pulling the cords do harm to all the internal connections and may harm the user. Avoid using extension cords and if necessary relieve suddenly after use. Avoid contact of water from all the electric appliances. Never use any metal pieces to dislodge something from an electrical appliance.

Let’s have a look at the outdoor precautions to be taken. Severe weather conditions may cause live power wires fall on the ground, don’t ever attempt to touch the wire and its surroundings. Inform the police as early as possible if noticed. Use wood ladders around the power lines instead of metal; also keep the ladders at a minimum distance of 10 feet away from the power lines. Make the surroundings of power line free from plants, branches of tree. Don’t use any wet tools. Keep the electric lines far from the reach of children.

Use wires and cables with ISI mark, Use lamp holders with lamp, use appropriate MCB and Use apt rated fuses. While repairing get the certified electrician. If any accident occurs, don’t touch the victim directly. Make him free from electric contact, i.e., to turn off the supply, give him first aid and call for medical assistance. If ant electric device catches fire, don’t try to put out it with water, immediately switch off the supply and use fire extinguisher.

Taking all these safety tips under consideration, stay free from harm and use electricity wisely and properly.
  • Seminar topics
  • Engineering Seminar Topics
  • Civil Engineering
  • Acoustic Couplers
  • Actuators
  • Digital Signal Processing
  • Electrical Generators
  • Electrical Powerline Networking
  • Lightning Arresters
  • Mechatronics Engineering
  • Neural Networks
  • Privacy Policy
  • Scada
  • Sensors
  • Vacuum Circuit Breaker
  • Varistors