Electrical Engineering Tour

All About Electrical Relays, Principles, Classification and Requirements

noreply@blogger.com (Admin) — Sun, 22 Jan 2012 12:31:00 +0000

Protective relays
Relay is a device by means of which an electric circuit can be controlled by the change in the same circuit or in other circuit. The primary function of the protective relay is to sense the fault in the system, compare the signal so obtained with the reference signal under normal conditions of operation and amplify the error signal such that the trip coil of the circuit breaker is energized and faulty section of the system is disconnected from the rest of the system.Under normal conditions of the system, a protective relay is required to keep itself alert such that in case of any emergency, the action may be taken almost instantneously.It should remain silent under normal condition. Under certain operating condition, the power system components are required to carry more than rated current on a temporary basis. During peak load condition, the power system components arc intentionally over-loaded. Under such conditions of operation, often known as abnormal condition, it is not necessary to disconnect the section from the system. When the operation parameters are unduly strained, the protective relays are required to energize the alarms such that proper precautions are taken.

The Basic Principles of Relays
In electromechanical relays, there are one or more coils, movable elements, contact system, etc. The operation of such relays depends on whether the operating torque/force is greater than the restraining torque/force.The relay operates, if the net force, F in equation given below is positive. Where F is the net force, Fo is the operating force and Fr is the restraining force. In other words, the relay operates only if the operating force is greater than the restraining force. In electromechanical relays, the operating torque is produced by electromagnetic attraction/electromagnetic induction/thermal effects of electric current. The restraining torque is given by springs.

The Classification of Relays
Protective relays are classified as follows according to their construction and the principle of operation.
1. Electromagnetic relays These are actuated by Direct current or Alternating current quantities.
2. Electomagnetic induction relays
3. Electothermal relays
4. Static relays these employ transistors or magnetic amplifiers to obtain the operating characteristic.
5. Electrodynamic relays these are operate on the same principle as moving coil instruments.
6. Under-voltage, under-current and under-power relays.
7. Over-voltage, over-current and over-power relays
8. Direntional or reverse current relays
9. Differential relays
10. Distance relays

The Basic Requirements of Protective System
The efficient protective relaying system should posses the following characteristics:
1. Speed
Minimum voltage and minimum fault time operate.
2. Selectivity
Maximum continuity of service by disconnecting the faulty part of the system.
3. Sensitivity
Capability of operating reliably under the actual desired conditions.

Protective Relays
These are the devices that detect abnormal conditions in electrical circuits by measuring the electrical quantities which are different under normal and faulty conditions. Due to abnormal conditions, voltage, current, phase and frequency may change. After detecting the fault, the relay operates to complete the trip circuit which results in the opening of the circuit breaker and isolating the faulty circuit.

All About Electrolysis and Batteries Facts and Tutorials

noreply@blogger.com (Admin) — Sat, 14 Jan 2012 08:23:00 +0000

1. The two main defects of the primary cells are local action and polarization.
2. Local action in the primary cell can be rectified by amalgamating the zinc electrode with mercury.
3. One factor affecting voltages of the primary cell is the types of plates and electrolyte.
4. Distilled or approved water is used in electrolytes because it prevents or slows down local action.
5. In electroplating, the positive electrode is called the anode.
6. The mass of an ion liberated at an electrode is directly proportional to the quantity of electricity which passes through the electrolyte. This statement is associated with laws of electrolysis.
7. The mass of material deposited over an electrode is proportional to quantity of electricity and electro chemical equivalent.
8. The condition of a secondary cell can be determined by the terminal voltage and strength of the electrolyte.
9. Nickle-cadium dry cell is becoming popular in power supplies for electronic calculators because it is rechargeable.
10. One advantage of a secondary cell is that it can be recharged.
11. Cell are connected in parallel to increase the current capacity.
12. Cells are connected in series to increase voltage output.
13. To obtain a high voltage of about 1.9 volts from a dry cell on would use magnesium cell.
14. While charging a battery, charge the battery in an airy room, remove the vent plugs during charging, keep flames etc. away from the battery and keep the charging current rate not more that 3 to 6 amperes.
15. If the internal resistance of a discharged battery is more it is not desirable to leave a lead storage battery in a discharged state for a long time mainly because plates will become sulphated.
16. To keep the terminals of a lead acid storage battery free from corrosion, it si advisable to keep the electrolyte level low.
17. If a sixty ampere hours battery has sixty seven ampere discharge rate, it will provide a current of six amperes for ten hours.
18. The ampere hour capacity of battery depends on the area of the plates.
19. Electrolyte of a storage battery is formed by adding suphuric acid to water.
20. Other types of accumulators besides the lead acid type are nickle cadmium batteries.
21. Electro-chemical equivalent is mass of the element liberated per unit of quantity of hydrogen.
22. Impurities in an electrolyte can cause an internal short circuit condition called local action.
23. The action of a dry cell is to change chemical action to electrical energy.
24. Polarization in dry cell can be got rid of by chemical means.
25. Gassing occurs in the process of charging an accurnuiator.

Terms used in Electrolysis

Anode
The plate or electrode through which the current enters the electrolyte or it may be defined as the plate or electrode connected to the positive terminal of supply.

Anions
The ions having negative charge are known as anions.

Atom
An atom is the smallest particle of matter which takes part in a chemical action.

Atomic weight
The atomic weight of an element is the relative weight of its atom compared with that of an atom of hydrogen. The atomic weight of H atom is taken as unity.

Cathode
The plate or electrode through which the current leaving the electrolyte or the plates connected to the negative terminal of supply mains.

Cations
The ions having positive charge are known as cations.

Chemical equivalent
The chemical equivalent of an element is the mass which is chemically equivalent to a unit mass of hydrogen.

Ions
When the current is passed through electrolyte, the electrolyte gets chemically decomposed, molecules of the electrolyte splits up into two parts known an ions.

Molecule
The molecule is the smallest particle of any substance which is capable of separate existence in a chemical form.

Valency
The valency of an element is the number of hydrogen atoms with which it will combine or with which it will replace in a compound.

Things You Should Know About Direct Current Generator Tutorials

noreply@blogger.com (Admin) — Thu, 05 Jan 2012 14:03:00 +0000

The Definition
We know that Direct Current Generator is a machine which converts the mechanical energy into electrical energy. The generator is usually driven by a steam engine or a diesel engine or an electric motor which are called prime movers.

The Principle
The principle of Direct Current Generator is it works on the principle of Faraday's Laws of electromagnetic induction. According to this law the conductors or armature are rotated in the magnetic field and electro magnetic force is induced in these conductors which is collected from the commutators fitted on the shaft of armature.

The Loop
The simple loop of a Direct Current Generator when the plane of the coil is at right angles to the lines of flux, the flux linked with the coil is maximum but the rate of change of flux linkage is minimum. As coil continues to rotate further, the rate of change of flux linkage increases, till it attains maximum value of 90 degree to 180 degree, the flux linked with the coil gradually increases resulting in decrease in induced electro motive force till it reduces to zero at 180 degree. A reversal of the trend occurs during next half revolution. For unidirectional current, the ends of the coil are connected commutation whose function is to reverse the connections to the rotating coil through fixed brushes and to collect the electro motive in one direction.

Four Reasons for failure of a generator to build voltage:
1.Defective contact of brushes with conmmutator due to dirt, insufficient pressure, tight brushes, dirty or rough commutators or projecting intersegment micas.
2. High resistance or open circuit in the shunt field circuit, faulty contact or burnt resistance in shunt regulators.
3. Loss of residual magnetism.
4. Reverse field connection or reversed speed.

Ten Reasons for sparking and Bad Bommutations:
1. Overload
2. Projecting intersegment micas.
3. Earth fault on armature
4. Armature short circuit
5. Incorrect brush position
6. Wrong grade of brushes
7. Reversed interpole coils
8. Brushes not properly bedded
9. Brushes not equally spaced
10. Worn Brushes

Question and answer about D.C. Generator
1. The armature of a DC generator is laminated to reduce eddy current loss.
2. In a shunt generator the voltage built up is generally restricted by the saturation of iron.
3. Copper loss in DC generators varies with load.
4. Full load efficiency of the generators is 92.51 percent.
5. Shunt generators are preferred for parallel operations.
6. In DC generator the ripples in the direct electro motive force generated are reduced by using commutator with large number of segments.
7. The functions of an interpole is to neutralize crossfield of armature reaction and obtain ideal commutation.
8. Equalizer connection are required when paralleling two compound generators.
9. A simple method of increasing the voltage of DC generator is to increase the speed of rotation.
10. In the commutation process it is the current which is getting reversed.

25 Tips You Need To Know About Current Electricity Engineering

noreply@blogger.com (Admin) — Wed, 28 Dec 2011 13:49:00 +0000

1. The curve representing Ohm's law in linear.
2. The condition in Ohm's Law is that the temperature should remain constant.
3. The Ohm's Law can be applied with certain reservations to electrolytes.
4. The presence of an electric current is made known by the effects produced.
5. An electric current can neither be seen nor touched.
6. Three important effects produced by the presence of a current heating, magnetic and electric shock.
7. Thermistor has negative coefficient of resistance.
8. International ohm is defined in terms of resistance of a column of mercury.
9. Resistors commonly used in power circuits are wire wound resistors.
10. When current flows through a heater coil it glows but the supply wiring does not glow because the resistance of heater coil is more than that of supply wires.
11. If the voltage applied across an electric press is reduced by 50 percent, the power consumed by the press will be reduced by is 25 percent.
12. In a parallel circuit the potential difference across the resistance is always constant.
13. In a series circuit the current is constant.
14. Voltage applied across a circuit acts as a force.
15. The resistance of carbon filament in carbon-filament lamps increases when its temperature is decreased.
16. The heating effect of current has an undesirable side effect in a vacuum cleaner.
17. When current flows in a conductor, the heat is produced because of inter atomic collision.
18. The temperature coefficient of a conductor is defined as the increase in resistance per ohm pwer degree centigrade.
19. The value of Joule's mechanical equivalent of heat,is equal of 4.2 Joules per calorie.
20. It was experimentally found by James Precott Joule that the heat produced in a current carrying conductor is proportional to the square of current.
21. The resistance of a conductor increases when its temperature is increased.
22. The specific resistance, depends upon the nature of the material of the conductor only.
23. Resistance of a conductor increases when its length increases.
24. The resistance of conductor is the hindrance by which the conductor opposes the flow of the current.
25. The minimum requirements to cause the flow of current are a voltage source and a conductor

All About Capacitors Electrostatics and Electric Lines of Force

noreply@blogger.com (Admin) — Tue, 20 Dec 2011 12:16:00 +0000

Some Important Characteristics of Capacitors
1.The current through capacitor is zero, if the voltage across it is not changing with time.
2. A capacitor is sort of open circuit to direct current.
3. The capacitor never dissipates energy but only stores it.
4. A capacitor resits an abrupt change in voltage across it.
5. A finite amount of energy can be stored in a capacitor even if the current through capacitor is zero, such as when the voltage across it is constant.
6. It is impossible to change the voltage across a capacitor by a finite amount in zero time, for this requires infinite current through the capacitor.

Electrostatics Question and Answer
1. Relative permitivity of vacuum is unity.
2. In the electric field, the potential is the work done in joules to bring positive charge of one coulomb from infinity to that point.
3. The unit of field intensity is newtons/coulomb.
4. Coulomb's law for the force between electric charges most closely resemble with Newton's law of gravitation.
5. Mica medium has highest value of dielectric strength.
6. The maximum value of potential gradient in cable occurs in conductor.
7.A region around a stationary electric charge has electric field.
8. Inside a hollow spherical conductor electric field is zero.
9. The effect of the dielectric is to reduce the working voltage.
10. Electrolytic capacitor is the most commonly used type but it has two disadvantages, namely low insulation resistance and suitable for Direct current only has high capacitance and low insulation resistance.
11. In a radio a gang condenser is a type of air capacitor.
12. A sphere of one metre redius can attain a maximum potential of three kilo volt.
13.The power dissipated in a pure capacitor is zero.
14. In a capacitor the eletric charge is stored in dielectric.
15. One farad is one coulomb per volt.
16. If a dielectri is placed in an electric field, the field strength decreases.
17. If the medium of a parallel plate capacitor consists of mica and air, the capacitance is increased by increasing the area of plates.
18. A capacitor with capacitance is charged through a resistance. The time constant of the charging
circuit is given by RC.

Properties of Electric Lines of Forces
A line of force is supposed to start or emanate, from a unit with a positive charge. A line of force does not form closed loop unlike a magnetic line of force. The line of force is always normal to the surface of the body at the point from where they originate or terminate. No two lines of force can across each other. An electric line of force in the same direction repel each other and those in opposite direction attract each other. There will be neutral point in this case between the two sphere. An electric line of force has a tendecy to take an easy path.

Transmission and Distribution Lines Key Facts and Tutorials

noreply@blogger.com (Admin) — Fri, 16 Dec 2011 09:19:00 +0000

Key Facts and Tutorials On Electrical and Distribution Lines

1. The economical section of a feeder can be obtain by applying Kelvin's law.
2. There should be be no break in the neutral, which is usually earthed at the supply end, of a two wire Alternating Current distribution system because excess current protection would be affected.
3. In actual practice the potential at the two feeding points is unequal. To calculate the voltage drop, the difference in potential is converted into ampere metres and the moments of the lower feeding point start from this initial value.
4. Uniformly loaded distribution fed at equal potential from both ends is treated like the distributor because the voltage drop is exactly halved.
5. Voltage drop in a uniformly loaded distributor fed at once end is calculated by assuming the whole of the load concentrated at middle point.
6. For Alternating current distribution the power factor of the load has to be taken into consideration and the calculations become cumbersome. The approximate method which gives results with in plus or minus five percent of the actual voltage drop involves calculating the centre of gravity of the load, resistance and reactance per double run and average power factor.
7. To determine the distribution of load at the point of minimum potential, the moments in ampere metres about of the feeding points must be equal to the moment in ampere metres about the other feeding point.
8.At the point of minimal potential in a distributor fed from both ends, the load at the point is supplied from right and left hand feeding points.
9. With point loads in a distributor fed at both ends, in order to determine the maximum voltages drop it is necessary to know the point of minimum voltage.
10. For a three wire Direct Current distributor fed at one end, if the total voltage drop in the neutral is positive it is added to the positive drop and deducted from the negative drop.

Limitation of high transmission voltage
a. Increased cost of line support
For high transmission voltage, the insulation required between the conductors and the earthed tower is more. This increases the cost of line supports.
b. High towers:
For high transmission voltage, the clearance between conductors and groundo should be more. Therefore, higher lower is required.
c. Longer cross arms:
FOr higher transmission voltage, distance between the conductors should be more. Therefore, longer arms are required.

World's Largest Nuclear Power Plant Located in Japan

noreply@blogger.com (Admin) — Mon, 12 Dec 2011 15:44:00 +0000

The Kashiwazaki-Kariwa Nuclear Power Plant is the World largest Nuclear Power Plant located at Japan the land in the towns of Kashiwazaki and Karina in Niigata Prefecture, Japan it has
4.2 square kilometer or equivalent of 1,038 acres site. The owner of the nuclear power plant is The Tokyo Electric Power Company or TEPCO. has an approximately 15 miles from the epicenter. There are seven units in which are all lined up along the coast line. The total capacity of the seven unit Nuclear Power plant is 8,212 mega watts since 1997 this is the largest station of its kind in the world. We know that this power station can produces sufficient energy that could cover on the domestic electricity use of about 16 million households.

Power Plant on an Earthquake Fault Line?
The Kashiwazaki-Kariwa nuclear power plant, closed since Monday following the major earthquake in the north of Japan is now known to be placed directly above a significant geological fault line.

Iran’s nuclear negotiator visits world’s largest power-plant
Iranian Supreme National Security Council Secretary and top nuclear negotiator Saeed Jalili has visited the world’s largest power plant in Japan.

Global Nuclear Power Outlook and Opportunities
Is any nuclear technology designed to extract usable energy from atomic nuclei via controlled nuclear reactions. The only method in use today is through nuclear fission, though other methods might one day include nuclear fusion and radioactive decay

source

All About Magnetism and Electromagnetism How It Works

noreply@blogger.com (Admin) — Thu, 01 Dec 2011 12:46:00 +0000

All About Magnetism and Electromagnetism How it works Tutorials
Magnet
A magnet is a substance that attracts pieces of iron. The phenomenon by which this attraction takes place is called magnetism.

Magnets are two types
Natural Magnets
The natural magnets are those iron ores which are obtained from mine and have the property of attracting iron pieces naturally.

Artificial magnets
The artificial magnets are those which are created by artificial means. An artificial magnet can be further divided into two types are temporary magnets and permanent magnets.

Temporary magnets
A temporary magnet is that in which magnetism remains temporarily. If a wire is wound on a soft iron piece and direct current is passed through the wire, then soft iron piece becomes a temporary magnet. It is because the iron piece will retain magnetism so long as the current is flowing.

A Permanent magnets are made from steel which is in general harder than soft iron apart from steel, alloys like cobalt steel, tungsten steel, etc. are also used as permanent magnets. These are used in Direct current machines to create magnetic flux, electrical instruments, moving coil loudspeaker etc.

Properties of Magnet
1. A magnet always attracts iron and its alloys
2. The magnet has two poles and when it is freely suspended it comes to rest pointing north and south directions. The end which points towards north is known as North-pole and the other which points toward south is known as South-Pole. The attracting power of the magnet is concentrated around two points one each at end ends.
3. Like poles repel and unlike poles attact each other.
4. If a magnet is broken into pieces, each pieces becomes and independent magnet.
5. A magnet can import its properties to any magnetic material.

Magnetic effect of electric current
When and electric current flows through a conductor, a magnetic field is set up all along the length of the conductor. In this connection following are the important points worth noting.
1. The magnetic lines of force are circular in a plane perpendicular to the current.
2. The field near the conductor is stronger and becomes weaker as we go away from the conductor.
3. The magnetic field becomes stronger if current is increased and vice-versa.
4. The direction of the field is reversed it current is reversed.

Facts of Magnetism and Electromagnetism
1. A magnet is a piece of iron or other magnetic material which can attract small pieces of thesematerial towards it.
2. A freely suspended magnet always rests in north south direction.
3. A natural magnet is called lodestone.
4. A magnet is able to attract nickel, cobalt and steel.
5. Externally, magnetic line of force travels north to south.
6. A material commonly used for shielding or screening magnetism is soft iron.
7. Magnetism is the property of certain materials of attracting small iron pieces toward them.
8. The magnetism that remains in a magnet after the magentising force has been removed is called its residual.
9. Iron becomes magnetized by induction when it is near to one end of a magnet.
10. Magnetic lines of force are called flux.

All About Electronics Binary Numbers Tutorials

noreply@blogger.com (Admin) — Sun, 20 Nov 2011 12:43:00 +0000

In digital system, however, only the digits 0 and 1 are used. This system is also known as binary system. It has a radix of 2. The binary system is used because digital circuits operate with square wave pulse waveforms that have only two amplitudes HIGH and LOW or ON and OFF.
There are many application of digital electronics in addition to the natural function of counting pulses. Even audio and video information can be converted into digital form for transmitting long distances and then reconverted to pulses. The advantage of digital circuits is the excellent signal to noise ratio.Binary to Decimal Conversion The process of converting from binary to decimal just involves counting the place values for base 2. From right to left, they are 1,2,4,8,16, 32,64, 128. etc. all in power of 2.

Binary Logic Gates
Logic gates are circuits the output voltage of which can be predicted from the conditions at the input.

Electronics Address
The rules of binary additions are:
0 + 0 = 0
0 + 1 = 1
1 + 0 = 1
We cannot have 1 + 1 = 2 in binary system. It is 1 + 1 = 0 plus carry of 1 to the next position towards left. This addition with carry in can take place in any column except the 1's place.

Half Address
Electronics address are constructed from logic gates to add binary numbers. A half adder combines 0 and 1 with carry of 1 to the next place, if required, but it has no terminal for carry in.

The Full Address
A full address has the provision for carry in and carry out. A full adder if formed by using two half adders and an OR gate. The output of the OR gate forms the carry out output. The full adder is for binary additions in all places except the 1's place.

FLIP FLOP
The flip flop or FF is a basic digital circuit having memory characteristic that can be used to store information. The circuit is bistable multivibrator that stays in one state until switched to the opposite state. The two outputs Q and Q are always opposite as HIGH and LOW logic levels.
The main types of flip flops are the R_S, with set and reset input terminals, D, and J_K. Clock input pulses are often used in the toggle mode, in which the Q and Q outputs are reversed by each clock input puslse.

Digital Electronics Question and Answer
1. Binary 111111 represents Decimal 51
2. Binary 1000 when subtracted from binary 1111, the result will be 111
3. Decimal 0.875 is represented in binary system as .111
4. The bolean expression for AND gates is A.B = Y
5. Integrated circuit logic gates contain the properties are resistors, diodes bipolar junction transistor
6. The abbreviation DTL stands for diode transistor logic
7. The basic DTL configuration is NAND gate
8. The schottky TTL, a Schottky diode is used primarily to
9. A schottky diode has no minority carriers and very low voltage drop in forward direction
10. In a RS flip flop no change occurs during disabled mode
11. In a digital counter the number of flips is equal to the number of bits required in the final binary count.
12. A temporary memory is destroyed when power is switch off
13. PROM is programmable read only memory
14. A digital voltage has anlog input and digital output
15. LCD display represents liquid crystal display

Current Interrupter Tutorials

noreply@blogger.com (Admin) — Thu, 10 Nov 2011 13:53:00 +0000

Current Interrupter Tutorials Facts, Definitions, Uses Etc.

Circuit Breaker
An electromagnetic device that opens a circuit automatically when current exceeds a predermined value. It is capable of interrupting large values of fault power MVA resulting from the faults on the power system. It consists of current carrying contacts called electrodes which, under predetermined conditions, separate to interrupt the circuit. An arc is struck between them when the contacts are separated. This arc is extinquished either by lengthening the arc, cooling the arc, or splitting the arc. Due to this, the arc resistance increases resulting in the system voltage becoming unable to maintain the arc and the arc gets extinguised.

HRC Fuse
High Rupturing Capacity cartridge fuse is a good interrupting device because it gives a fast fault clearing and exhibits property of cut-off. It is useful in low and medium voltage installation to provide overload and short-circuit protection. The fuse element is of copper alloyed with tin. Its characteristics vary with the type of material and the shape of fuse element. The rated current of the fuse is the current which it can carry continously without deterioration.

Switchgear
The name given to a family of devices covering a wide range of equipment concerned with switching and interrupting the currents during normal and abnormal conditions. The equipment associated with controlling, protecting, regulating and measuring also belong to the switchgear family. It includes switches, fuses, Circuit breaker, isolator, relays, Control panel, metering panels lighting arresters, Current transformer, Potential transformer, and other associated items. The circuit breakers are assited by other components of the protective scheme. A switch is used for opening and closing the circuit. Fuse is used for over-current protection. The purpose of switching and protection is served by the swithgear. A circuit breaker is the switching and interrupting device in a switchegear.

Reactors
The purpose, of reactors incorporated in circuit breakers is to limit the short-circuit current flowing to a safe value thus providing protection of instruments. The concist of large coils of high self-inductance and very low resistance. Main type of reactors are magnetically shielded reactor, and the shielded reactor.

Answer all Frequent Questions About Circuit Breaker
1. The function of protective relay in a circuit breaker is to close the contacts when the actuating quantity reaches a certain predetermined value.
2. Low voltage circuit breakers have rated voltages of less than 1000 volts.
3. When A high voltage Alternating current circuit breaker is tested for endurance, it is tested for at least 1000 opening closing operations.
4. For high voltage Alternating Current circuit breaker, the rated short circuit current is passed for 3 three second.
5. Vacuum is not a type of the contactor for circuit breaker.

Current Interrupter Tutorials

Network Theorem Kirchoff's Law Tutorials

noreply@blogger.com (Admin) — Fri, 04 Nov 2011 02:24:00 +0000

Kirchoff's Law Facts and tutorials

Kirchoff's Current Law (KCL)
In any electrical network. The algebraic sum of the currents meeting at a point or junction is zero. Here it is assumed that incoming current to be positive and outgoing current to be negative.

Kirchoff's Voltage Law (KVL)
The algebraic sum of the products of currents and resistance in each of the conductors in any closed path or mesh in a network plus the algebraic sum of the electromotive force in the path is zero.

Sign Conventions for Kirchoff's Law

A rise in voltage shall be given a plus sign and fall in voltage drop shall be given a negative voltage sign.
In a resistance if we traverse in the direction of current. It is a voltage drop. This is because the current flows from higher potential to lower potential. This is voltage drop. It is given to be a negative voltage sign.
In a resistance if we go in the direction, opposite to direction of flow of current, we are going from lower potential to higher potential. Going from lower to higher potential means voltage rise and shall be given a positive voltage sign.
In a battery if we go from negative voltage sign terminal of battery to positive voltage sign this is voltage rise. This shall be given a positive voltage sign.
In a battery if we go from positive voltage sign terminal of a battery to negative voltage sign terminal, this is voltage drop. It should be given a negative voltage sign.

Method to solve circuits by kirchoff's Law

Draw a large clear diagram of the network to be solved showing the values of all resistors and the polarity and values of all sources of electromotive force letter the nodes and number of meshes.
Arbitrarily choose direction for the currents in each branches. There is no point in wasting time for trying to indicate the true current directions since, in the majority of the cases, it is quite impossible to tell.
Place plus and minus signs on each resistors to indicate the direction of the potential difference across it. These potential differences must be constant with the directions of the assumed branch currents.
Write an equation for each in the network, using Kirchoff's second law, traversing the meshes in the clock wise direction.
Solve the resulting simultaneous equations.

Take note that, it should be noted that Kirchoff's law are applicable both direct current and alternating current. Voltage and current, However in the case of alternating current and voltages any electromotive force or self-inductance that existing across a capacitor should also be taken into account.

Free pdf file for network Theorem
The fundamental laws that govern electric circuits are the Ohm’s Law and the Kirchoff’s
Laws.

Electrical Circuit Network Theorems Definitions and Key Facts

noreply@blogger.com (Admin) — Thu, 03 Nov 2011 14:20:00 +0000

Definition Terms of a Network Theorems and key facts

Active network
A Network containing one or more sources of electro motive force ( e.m.f) is known as an active network.

Branch
A single path containing one simple element which connects one node to any other node is know as branch.

Bilateral Circuit
A circuit having identical properties in either direction is know as bilateral circuit. Transmission line is bilateral.

Circuit
A circuit is a conducting part through which either an electric current flows or is intended to flow.

Linear Circuit
A linear circuit is one whose parameters are constant.. do not change with voltage or current.

Non-Linear Circuit
It is that circuit whose parameters change with voltage or current.

Node
A point at which two or more elements have a common connection is called a node.

Parameters
The various elements of an electric circuit are called its parameters like resistance, inductance and capacitance. These may be lumped or distributed.

Unilateral Circuit
It is that circuit whose properties changes with the direction of its operation. A vaccume tube rectifier is a unilateral circuit.

Key facts on Network Theorems

Kirchhoff's law is applicable to ac ( alternation current) as well as DC ( direct current) circuits.
An ideal current source has zero internal conductance.
A closed path made of several branches of the network is known a loop.
An ideal voltage source is that which has zero internal resistance.
A passive network has neither source of current nor source of e.m.f. ( electro motive force).
The relationship between voltage and current is same for two opposite directions of current in case of bilateral network.
A passive network has neither e.m.f ( electro motive force) source nor current source.
Heater coil is not a non-linear element.
Milman's theorem enables a number of voltage for current source to be combined directly into a single voltage or current source.
The thevenin's theorem is applicable to a network of the alternating current and direct current circuit both.
For open circuited condition of thevenin's theorem, all sources of electromotive force in the network are replaced by their internal impedance.
Reciprocity theorem is valid for passive network only.
In compensation theorem a network containing generator can be replaced by its zero internal impedance.
The most important feature of superposition theorem application is to find direct current level in a network that has both sources.
Open circuit voltage is the p.d. between two points when the impedance between these points is infinity.
Norton's theorem reduce a two terminal network to a constant current source and an impedance in parallel.
The superposition theorem requires as many circuits to be solved as there are sources.
For a maximum power transfer, according to maximum power transfer theorem, source impedance must be complex conjugate of load impedance.
In case the delta connected circuit, when one resistor is open, power will be reduced by 1/3.
The superposition theorem is applicable to linear responses only.

All About Electric Induction Motors Tutorials

noreply@blogger.com (Admin) — Mon, 24 Oct 2011 10:33:00 +0000

All About Induction Motor Facts, Tutorials and Important Information

Advantages of a three phase induction motor:
This is simple in construction. It is robust. It si almost unbreakable.
- It requires minimum care and maintenance.
- For a given horse power cost of induction motor is less.
- It has high efficiency
- It has a reasonably good power factor.
- It is self starting

Disadvantages of a three phase induction motor:
- Its speed can not be varied without loss of efficiency.
- Its speed decrease with the increase of load.
- It has inferior starting torque

Principle of Induction Motor:
When a three phase supply is given to the stator, a rotating field produces induced e.m.f. in rotor windings which cause induced currents tend to propose the action, producing them and therefore they circulate in such a manner that a torque is produced in the rotor tending it to cause it to flow the rotating field and thus reduce the relative motion which is producing the induced currents.

Key facts on Induction Motor:
- Squirrel cage induction motor has very small starting torque.
- Just like a D.C. shunt motor, the speed of an induction motor operating in stable region decreases with increase in load.
- Magnetic flux produced due to the stator winding with three phase current of frequency and which is of constant value, rotates at synchonous speed. If the number of pole of the motor. the synchronous speed is given by Ns = 120f/P.
- An induction motor rotor runs at a speed which is always less than the speed of the stator field.
- In a three phase induction motor the torque increases with the increase in supply voltage.
- Improvement in the power factor in an induction motor increase the torque and decrease the current due to increased impedance.
- Two of the power supply terminals to a three phase induction motor got interchanged during recondition after maintenance of the motor, when put back into service, the motor will rotate in the reverse direction to that prior to maintenance.
- If the air gap of the induction motor is increased the magnetizing current will increse.
- In a slip ring induction motor resistance is connected in rotor phases to increase the starting current.
- For a three phase wound rotor induction motor, and increase in rotor resistance effects the motor performance in the starting current decrease.
- It is advisable to avoid line starting of induction motor and use starter because motor takes five to seven times its full load current.
- A change of five percent in the supply voltage of a three phase induction motor will produce to its torque a change of approximately ten percent.

All About Electrical Cables and Wires Tutorials

noreply@blogger.com (Admin) — Fri, 14 Oct 2011 09:20:00 +0000

A cable is a length of single conductor, generally with several wires stranded together, or two or more conductors, each provided with its own insulation and laid up together. The insulated conductors may or may not be provided with an over all protective converging. The conductor with its insulation but without mechanical protection is known as the core of the cable.
A cable consist of the following three parts.
1. Conductor: It provides conducting path of electric current.
2. Insulation: An electrical insulating medium that prevents direct contact or unsafe proximity between the conductor and other objects.
3. External protection: Protects against mechanical damage, chemical or electromechanical attact, free or any other deleterious external influences. Copper used on overhead lines is generally hard drawn for providing adequate mechanical strength. However in case of cables, copper in annealed condition is used. Aluminum being lighter is extensively used in cables, However, joining of aluminum conductors calls for the use of special techniques and expertise.The size of conductor depends on the current rating of the conductor.Classification of Cables based on Insulation:On the basis of insulation, the cables are classified as under: Paper insulated cables: In these cables paper is wound on the conductor in successive layers to achieve the needed dielectric strength. Such cables are manufactured in various sizes from 5 mm squared to 500 mm squared cross-section of conductor and voltage ratings up to 33kv.The cable are provided with steel armour made up of galvanised steel wires or shielding tap. The outer sheath on the cable provides protection against external forces on the cable. The metallic shielding around the conductor is used to control the electrostatic voltage stress, reduce corona effect and to decrease the thermal resistance. Metallic shielding in only 3 to 5 mm thick. Lesser thickness reduces circulating currents and power loss.

The Flow Of Electricity and How Grounding Is Important In the Systems

noreply@blogger.com (Admin) — Mon, 03 Oct 2011 15:11:00 +0000

The Flow Of Electricity and How Grounding Is Important In the Systems Tutorials
By: IIEE

The electric power utility provides a ground somewhere in its local distribution system; therefore, there is a ground wire in addition to the hot wires within the service drop. This ground can be seen at the power pole that contains the step down transformer.In addition to the ground connection provided by the electric utility, every building is required to have an independent ground, callead a"system ground." The system ground provides for limiting the voltage upon the circuit, which might otherwise occur through exposure to lighting, or for limiting the maximum potential to ground due to normal voltage. Therefore, the system ground's main purpose is to protect the electric system itself limited protection to the user.The system ground serves the same purpose as the power company's ground, however, being closer to the building it has a lower resistance. The equipment ground on the other hand, protects man from potential harm during the use of certain electrical equipment. The system ground should be a continuous wire of low resistance and of sufficient size to conduct current safely from lightning and overloads.

RESIDENTIAL ELECTRICAL SYSTEMS
ELECTRICAL FUNDAMENTALS - Think of a pipe or a garden hose. When you turn on the water, it moves through the pipe and out the faucet or hose end. In a similar way , you can think of electricity as a current of very tiny particles (electrons) flowing inside a wire and through a light bulb or an appliance that’s been switched on.

How fast does electricity travel?
Electric current is defined as the ordered movement of charge. The charge that moves in
electricity could be ionic charges in a liquid or a gas (right). However most of us usually
think of electrons as the charge carrier in electricity. So we will refine the question
further by saying “How fast is an electric current comprising of moving electrons?”.

Measuring Electricity
Electricity makes our lives easier, but it can seem like a mysterious force. Measuring electricity is confusing because we cannot see it. We are familiar with terms such as watt, volt, and amp, but we do not have a clear understanding of these terms. We buy a 60-watt light bulb, a tool that requires 120 volts, or an appliance that uses 8.8 amps, but we don’t think about what those units mean.

The Flow Of Electricity On Transmission Lines Engineering

noreply@blogger.com (Admin) — Mon, 03 Oct 2011 15:06:00 +0000

The Flow Of Electricity On Transmission Lines Engineering Tutorials
By: IIEE

Electricity is usually generated by a generator that converts mechanical energy into electrical energy. The electricity is then run through a transformer where voltage is increased to several hundred thousand volts and in some instance to a million or more volts. This high voltage is necessary in order to increase the efficiency of power transmission over long distances.This high-transmission voltage is then stepped down reduced to normal 110 volt/220 volt household current by a transformer located near the point of use residence. The electricty is then transmitted to the house by a series of wires call a service drop. In areas where the electric wiring is underground, the wires leading to the building are burried in the ground. In order for electric current to flow, it must travel from a higher to a lower potential voltage. In an electrical system the hot wires black or red are at a higher potential that the neutral or ground wire white or green. Therefore, current will flow between the hot wires and the neutral or ground wires. The voltage is a measure of the force at which electricity is delivered. It is similar to pressure in a water supply system. Current is the quantity of flow of electricity. It is similar to measuring water in gallons per second. A watt is a measure of how much power is flowing. Electrity is sold in quantities of watt-hour. The earth, by virtue of moisture contained within the soil, serves as a very effective conductor. Therefore, in power transmission, instead of having both the hot and neutral wires carried by the transmission poles, one lead of the generator is connected to the ground, which serves as a conductor. Only hot wire are carried by the transmission towers. At the house or point where the electricity is to be used the circuit is completed by another connection to ground.

Tracing The Flow Of Electricity
The mesh Structure of high voltage transmission networks provides a large number of possible routes by which electrical power can flow from the sources generators to the sinks grid supply points.

Circuits and the Flow of Electricity
To understand current electricity, many vocabulary words must be introduced. The first
part of this lesson uses a hands-on, problem-solving activity that helps students define the
vocabulary terms and demonstrate the terms’ relationships. After gaining foundational
understanding, students create their own circuits.

FREE Electrical Safety Fundamental Basic and tips PDF

noreply@blogger.com (Admin) — Mon, 12 Sep 2011 15:46:00 +0000

The most apparent requirements in determining unsafe equipment are related to the exisitence of the power supply, the types, locations and conditions of the wiring in use, and the existence of the number of wall outlets or ceiling fixtures required by the PEC and NEC, and their condition. In making investigations of unsafe equipment, these pdf ebook will serves as useful guides you can download it freely.

Wiring Regulations free ebook
plays a key role in the electrical installation industry in terms of standards and safety and is known for its independent and trusted voice in this sector.

ELECTRICAL SAFETY HAZARDS AWARENESS
This guide should be used by instructors to supplement the non-electrical worker training module presentation.

BASIC ELECTRICAL SAFETY
The concepts discussed herein are intended to provide explanation and clarification of basic electrical safety for individuals who have little or limited training or familiarity with the field of electricity. Basically, there are two kinds of electricity - static stationary and dynamic moving. This module is about dynamic electricity because that is the kind commonly put to use.

Electrical Safety
Statutes and Regulations,Alaska Department of Labor After the American National Standards Institute approves a new, published edition of the National Electrical Code or a new, published edition of the National Electrical Safety Code, the Department of Labor and Workforce Development may, by regulation, adopt the most recent codes to constitute the minimum electrical safety standards of the state.

Fundamentals of Electrical Safety
It is important to note that all electrical systems must be properly maintained, so as to reasonably prevent danger of electric contacts. Electrical safety is not exclusively defined by the prudent conduct of individuals in the presence of energized objects. A sensible attitude toward electrical equipment may only prevent direct contact, that is, an accidental contact with parts normally live (e.g., energized conductors, terminals, bus bars inside of equipment, etc.

Basic Electricity Definition and Engineering Terms

noreply@blogger.com (Admin) — Mon, 05 Sep 2011 14:16:00 +0000

Basic Electrical Engineering Or Electricity Definition.
Electricity and Magnetism free ebook

source

Ampere
Unit used in measuring intensity of flow of electricity. Symbol for it is "I".

Alternating Current(AC)
Electric current reversing its direction of flow at regular intervals. For example, it would alternate sixty times every second in a sixty cytle system. This type of current is commonly found in homes.

Bare Conductor
Wire or cable with no insulation or covering

Current
Flow of electricity through a circuit; either AC or DC.

Circuit
Flow of electricity through two or more wires from the supply source to one or more outlets and back to the source.

Circuit Breaker
Safety device used to break the flow of electricity by opening the circuit automatically in the event of overloading, or used to open or close it manually.

Conductor
Any substance capable of conveying an electric current, in the home, copper wire is usually used.

Covered Conductor
WIre or cable covered with one or more layers of insulation.

Conductor Gauge
Numerical system used to label electric conductor sizes, given in American Wire Gauge(AWG) or square millimeters diamter.

Cable
Conductor insulated from one another.

Direct Current(DC)
Electric current flowing in one direction. This type of current is commonly found in industries.

Electricity
Energy used to run household appliances and industrial machinery; can produce light, sound, heat and numerous other uses.

Frequency
The number of periods per unit time stated in cycles per seconds or Hertz. For alternating current power lines, the most widely used frequencies are 60 and 50 Hertz.

Fuse
Safety device that cuts off the flow of electricity when the current flowing through the fuse exceeds its rated capacity.

Ground
To connect with the earth as to ground an electric wire directly to the earth or indirectly through a water pipe or some other conductor. Usually a green colored wire is used for grounding the whole electrical system to the earth. A white wire is usually to ground individual electrical components of the whole system.

Impedance
A measure of the complex resistive and reactive attributes of a component in an alternating current circuit

Insulator
Material that will not permit the passage of electricity.

Neutral Wire
Third wire in a three wire distribution circuit, it is usually white or light gray and is connected to the ground.

Resistance
Restricts the flow of current; Unit of resistance is Ohm. The more resistance, the less the current flows.

Service
Conductor and equipment for delivering energy from the electricity supply system to the wiring system of the premises.

Service Drop
Overhead service connectors from the last pole or other aerial support to and including the splices, it any, connecting to the service entrance conductors at the building or ther structure.

Service Panel
Main panel or cabinet through which electricity is brought to building and distributed. It contains the main disconnect switch and fuses or circuit breakers.

Short Circuit
Break in the flow of electricity due to evercurrent resulting from a fault of negligible impedance between live conductors having a difference in potential under norma operation condition.

Voltage Drop
Voltage loss when wires carry current. The longer the cord, the greater the voltage drop.

Volt
Unit for measuring electrical pressure or force, known as electromotive force. Symbol for it is "E" or "V".

Wires
Conductors carrying the electric current or power to the load; usually black or red.

Watts
Unit of electric power. the formula is Volts time Amperes equals watts

Puzzle: Basic electrical terms
Basic electrical terms cross word puzzle

Links on Electrical Formulas
Links On Free download Electrical Engineering Ebooks

IIEE-ICA Electrical EngineeringTechnical Manuals free pdf ebooks

noreply@blogger.com (Admin) — Tue, 30 Aug 2011 11:43:00 +0000

Last Augusts 25-27, 2011 The International Copper Association – South East Asia and Institute of Integrated Electrical Engineers of the Philippines, Inc. gaves us a Three free books with CD of free ebooks a pdf file on the 15th Southern Mindanao Regional Conference. The three free books all about the abstract for the presentation of the contents of three technical manuals through the initiative of international copper association southern (ICASEA) and administered, executed, and implemented of ICA, a non-profit organization promoting the efficient use of copper in the industry. The main objective of ICASEA is to advance copper as the material of choice for current makets and new applications given its superior attributes in terms of technical performance, aesthetic value, sustainability, essentiality for life, and its contribution to a higher standard of living listed below are the following
which is ready to download a pdf file.

Power Transformer
This manual shows how a transformer can be put to use appropriately in a particular situation. The purpose of this manual is to facilitate the physical understanding, selection, ordering, operation, and maintenace of transformer. The target readers are personnel involved in the various stages of a transformer's sevice life from planning the investment to the disposal of the transformer after use.

Electrical Motors and Drives
This manual deals primarily with small and medium sized induction motors which are the most common type of alternating current motor including asynchronous motor starting systems. They are internationally standardized and are efficienctly in long production runs. The combination of new materials and more sophistacated methods for calculation, design and production have made the modern three phase induction motors a robust and realible prime mover.

Power Cables and Wire
Power Cable and Wires technical manual was written to address the needs of by consumers, specifiers, and purchasers to have a ready reference guide in correctly specifying or ordering the appropriateness of cables and or wires, from the conductor to the insulator, are each discussed in this manual so as to educate or inform the reader of its fundamental use or purpose to the final product.

All About Electric Motors machinery Controls links tutorials

noreply@blogger.com (Admin) — Wed, 24 Aug 2011 14:24:00 +0000

Handbook of Small Electric Motors free ebook - I Found this site full of free ebook on electrical machinary

Electric Motor Controls
understanding the many various control devices available and their uses and limitations becomes an important part related to reliable operation and protection of the motor and the personnel using the motor.Certain pieces of motor control equipment can accomplish multiple functions from each of the topics or categories.

Instrumentation And Control
Tutorials on Electric Actuators. Electrically actuated system are very widely used in control systems because they are easy to interface with the control systems which are also elecric and because electricity is easily available unlike fluid power which require pumps and compressors.

The Three Phase Induction Motor
Thomas Edison He invented the incandescent lamp in 1879 and began immediately to develop a power generating and distribution system to promote it. His first power plant opened in new York City in 1882 and several others were built over the next few years. Most of the power generated by Edison’s plants went to lighting customers; however, DC motors were in use in industry by the 1880’s. Although Edison’s efforts were a limited financial success, it was soon recognized that DC systems suffered heavy power losses in transmissions over any distance.

A Brief Tutorial On Machine Vibration
These benign vibrations are characteristic of regular operation of a machine doing what it is supposed to do. The amplitudes will vary from machine to machine and are a measure of the quality of manufacturing and load condition. The presence of these benign vibrations at “normal” levels provides a comfortable feeling that the machine is still alive.

Motor Basics
Motors convert electrical energy to mechanical energy.Engines convert chemical energy to mechanical energy. Operating Principle, Motor Parts, Enclosure, Stator, Rotor, Wound Rotor Motors, Bearings, Other Parts,

All electric motors are governed by the laws of electromagnetism, and are subject to essentially the same constraints imposed by the materials copper and iron from which they are made. We should therefore not be surprised to Wnd that at the fundamental level all motors – regardless of
type – have a great deal in common. Although there are many diVerent types of converters, all except very low-power ones are based on some form of electronic switching. The need to adopt a switching strategy is emphasised in the Wrst example, where the consequences are explored in some depth. We will see that switching is essential in order to achieve high-eYciency power conversion, but that the resulting waveforms are inevitably less than ideal from the point of view of the motor.

NUCLEAR ENERGY BASIC PRINCIPLES FREE TUTORIALS

noreply@blogger.com (Admin) — Mon, 08 Aug 2011 14:21:00 +0000

NUCLEAR ENERGY BASIC PRINCIPLES

There are two common methods of producing nuclear energy from an atom and these are by:
1. NUCLEAR FISSION
2. NUCLEAR FUSION

BASIC PRINCIPLES
In the FISSION process, an atom absorbs a neutron, then it splits itself into two lighter fission elements. These fission elements have a lower mass than that of the original atom. This mass difference is converted into energy in the form of heat, (E = m x c sq.) ; Uranium (U-235) is the most widely used by nuclear plants for its nuclear fission, because this atom could be easily split apart; Spent fuel of U-235 is RADIOACTIVE. two atoms of light elements into one atom of a heavier element, the resulting mass is less than that of the fusing atoms; This mass difference is converted to energy according to Einstein’s equation, E = mc²; Fusion fuel is sourced usually fromdeuterium which is a hydrogen isotope. It is not radioactive and can be extracted from lake and ocean waters; However, fusion reactor is still far from developing commercially, due to its uncontrollable fusion reaction

NUCLEAR REACTORS
There are two kinds of nuclear reactors commonly used by nuclear power plant via nuclear fission for power generation and these are:

1. PRESSURIZED WATER REACTOR (PWR)
2. Boiling Water Reactor (BWR)

NUCLEAR PLANT ACCIDENTS
In 1979, the Three Mile Island nuclear plant accident in USA happened due to a combination of personnel errors, deficient design, and component failures that led to a partial meltdown of reactor no. 2 (852 MW); Fortunately, the reactor vessel is adequately strong and contained the damaged fuel; In the case of the Chernobyl nuclear plant in Ukraine, in April 1986 reactor no. 4 (1000 MW) exploded due to reduced water coolant flow that raised the output uncontrolled; The accident resulted to a core meltdown and again the cause was attributed to human errors and faulty design.

NUCLEAR ENERGY OPTION OF MUSLIM STATES
Leading in the region, Iran will be operating its first nuclear power plant under the direct supervision of
Russia before the end of this year; United Arab Emirates has engaged a South Korean Group to build 4 nuclear power plants(4 x 1,400 MW) to start construction by Dec. 2010; Pres. Mubarak of Egypt has just issued the ‘go signal’ to start building the first nuclear power plant to be sited on the Mediterranean cost; In the mean-time, the rest of the Middle East countries each has singed nuclear energy agreement/accord with either France, Japan, Russia, Korea, U.S.A., etc.

HOW DOES NUCLEAR POWER PLANT WORKS?

Electrical Transmission lines Free PDF ebook download

noreply@blogger.com (Admin) — Mon, 01 Aug 2011 15:25:00 +0000

List of Electrical Engineering Ebooks

Electrical Characteristics Of Transmission lines
Transmission lines are generally characterized by the following properties: balance-to-ground characteristic impedance attenuation per unit length velocity factor electrical length, Skin effect is a phenomenon that occurs in conductors carrying an AC current. As the frequency increases, the current tends to be concentrated near the surface of the conductor. At RF, almost no current flows down the center of wire. It is all on the surface.

Electrical Power Transmission Lines
Properties Values, and Compensation, The effects of electric power transmission lines on property values is a controversial issue, and conventional procedure appear to be a major source of public dicontent over the sitting of transmission lines.

Review of Transmission-line Theory
The term transmission-line in electromagnetics is commonly reserved for those structures which are capable of guiding TEM waves. Transmission-lines are a special class of the more general electromagnetic waveguide. TEM waves can only exist in structures which contain two or more separate conductors. Coaxial lines, parallel plates, and two-wire lines are examples of practical transmission-lines.

Wireless Sensor Network for Electric-Transmission
Line Monitoring, Obtain electric power line (or grid) information in real time independent of owners/operators of grid assets. Provide source of information that Government can use to obtain situational awareness of the electrical grid.

Introduction To Transmission Lines and Waveguides
Is a device designed to guide electrical energy from one point to another. It is used, for example, to transfer the output rf energy of a transmitter to an antenna. This energy will not travel through normal electrical wire without great losses. Although the antenna can be connected directly to the transmitter, the antenna is usually located some distance away from the transmitter. On board ship, the transmitter is located inside a radio room, and its associated antenna is mounted on a mast.

Transmission Line Protection Principles
Factors like de-regulated market environment, economics, rightof- way clearance and environmental requirements have pushed utilities to operate transmission lines close to their operating limits. Any fault, if not detected and isolated quickly will cascade into a system wide disturbance causing widespread outages for a tightly interconnected system operating close to its limits.

Transmission Line Corona
Under certain conditions, the localized electric
field near energized components and conductors can produce a tiny electric discharge or corona, that
causes the surrounding air molecules to ionize, or undergo a slight localized change of electric charge.
Utility companies try to reduce the amount of corona because in addition to the low levels of noise that
result, corona is a power loss, and in extreme cases, it can damage system components over time.

The Nature of Electricity
The current transmission grid includes not only transmission lines that run from power plants to load
centers, but also from transmission line to transmission line, providing a redundant system that helps assure the smooth flow of power. If a transmission line is taken out of service in one part of the power grid, the power normally reroutes itself through other power lines to continue delivering power to the customer.

Basic electricity Theory and Tutorials pdf link free download

noreply@blogger.com (Admin) — Mon, 25 Jul 2011 14:03:00 +0000

Source of Free Ebooks

Electrical Studies for Trades
Discussion of general wiring practices and circuit protectors, as well as an introduction to transformers and three phase and single phase motors, rounds out the comprehensive coverage.

Basic Electricity
Electricity is defined as the movement of electrons from one atom to another. In order to understand electricity a basic explanation of the atom is needed. Electrons - Negatively charged particles orbiting around a nucleus. Protons - Positively charged particles in the nucleus. Neutrons - Uncharged particles in the nucleus that stabilize the protons.

University of Manchester
The intention of this lecture is to describe basic electrical characteristics in a qualitative way.
The objectives are provide some basic knowledge of analogue electronics, to give some “feel” for electronic effects on digital circuits

Battery Tender
Charge Polarity, Charge Polarity, Ohm's Law, Battery Chargers and Batteries, Nominal Voltage Ratings, Resistance, Charging a battery, equivalent of Electric Circuits, Time required to charge battery.

Electrical Circuit Theory
Introduce basic wiring diagram symbols, show how series parallel circuits are used on the vehicle, introduce the basic electrical diagnostic tools, review the components of a basic automotive electrical circuits, review the basic electrical concepts of voltages, amperage, and resistance.

Basic Principles and Functions of Electrical Machines
In the synchronous machine, direct current is supplied to the rotor and Alternating Current (A.C.) flows in the stator. On the other hand, a D.C. machine is a machine that is excited from D.C. sources only or that itself acts as a source of D.C. [5]. It is a common practice in industry to employ A.C. motors whenever they are inherently suitable or can be given appropriate characteristics by means of power electronics devices.

Basic Electrical Measurements
Voltmeters read across the circuit or load under test. This means that typical readings are taken with the
circuit in operation. In fact, it would be meaningless to measure the voltage across a load that was not in operation because the result should be zero volts. Right? There is, however, validity in measuring the
open circuit supply voltage as well as the supply potential when under load. This measurement will tell us just how much the load is effecting the supply.

Free Electrical Capacitor Bank Tutorials PDF ebooks Dowload Diagram

noreply@blogger.com (Admin) — Mon, 18 Jul 2011 13:51:00 +0000

Almost Electrical company are always improving the quality of the electrical supply. Those are
they use capacitor-banks speaking of this bank are : Shunt capacitor banks, Power Factor in ac machines, Delta Connected Capacitor banks, Undergrounded wye, grounded wye connected, power factor correction etc. You can download a free pdf file ebooks below.

Shunt Capacitor Bank Fundamentals
And protection, This paper reviews principles of shunt capacitorbank design for substation installation and basic protection techniques. The protection of shunt capacitor bank includes: a) protection against
internal bank faults and faults that occur inside the capacitorunit; and, b) protection of the bank
against system disturbances. Are mainly installed to provide capacitive reactive compensation/
power factor correction.

Shunt Capacitor Bank Swithing Transients
A Tutorial and case Study,power systems may damage key equipment, potentially having
a great impact on system reliability. These transients may be introduced during normal
switching operations, interruption of short circuits, lightning strikes, or due to equipment
failure. Phasor analysis or other simplified analysis methods are usually inadequate due
to system frequency dependencies and nonlinearities.

Analyzing Transmission Capacitor Bank
This paper will cover operations of banks that have
microprocessor relays utilizing the voltage differential protection scheme. Examples of several
unique events are included. While these events may be unusual, the same analysis can be applied
to most, if not all, capacitor bank operations.

Capacitor Banks Protection
Mov Protection of series capacitor banks, When capacitors are inserted in a transmission line, the series capacitance effectively compensates for the inherent inductance in the line to lower the total impedance. This in effect allows the circuit to transfer more energy with less heating of the lines. The series banks are generally located at either end of the section of the transmission line in one of the existing substations.

Fuseless Capacitor Banks
using Digital Relays, discuss the protection of shunt capacitors banks and present innovative techniques for fuseless shunt capacitor banks using digital relays to provide complete and economical
protection. These techniques eliminate the need for high voltage transducers for voltage differential
protection, provide more sensitive protection, and make the relay settings insensitive to system
voltage variations, as well as to capacitance variation caused by temperature.

Power Factor Correction Evaluation
Power factor correction needs are
calculated and the impact of the existing capacitors bank (provides about 600 kvar of compensation) is illustrated. The capacitor increases distortion levels at the 7th and 11th harmonics, resulting in overall voltage distortion levels exceeding 5% on the 480 volt system.

Free Pdf Electrical Conversion, Chart Factors SI units

noreply@blogger.com (Admin) — Mon, 11 Jul 2011 14:46:00 +0000

You may need to convert voltage, amperage and electrical specifications from equipment into kW, kVA and BTU information that can be used to calculate overall power and HVAC requirements. The following section addresses the process of taking basic electrical values and converting them into other types of electrical values.

The Table of Contents of units and conversion factors of the Free pdf download are:
Decimal Multiples and Submultiples
Description of Units Mechanical, Electric, Magnetic
Equivalent Units mksq System
Dimensions of esu and emu Electric and Magnetic Quantities
Dimensions and Units for Physical Quantities — mksq System
Conversion of mksq Units to Gaussian Units
Conversion Factors:
Plane Angle
Solid Angle
Length
Area
Volume
Mass
Density
Time
Speed
Force
Pressure
Energy, Work, Heat
Specific Energy
Specific Energy Per Unit Temp
Power
Heat Flux
Heat Transfer Coefficient
Thermal Conductivity
Absolute Viscosity
Kinematic Viscosity
Electric Charge
Electric Current
Electric Potential
Electric Resistance
Electric Resistivity
Capacitance
Inductance
Magnetix Flux
Magnetomotive Force
Magnetic Field Strength
Magnetic Vector
Electromagnetic Constants of Free Space
Electromagnetic Constants of Materials
Some Important Dimensional Constants
Some Important Dimensionless Groups
The Perfect Gas Law
Nomenclature, Definitions and Equations
Values of Universal Gas Constant, Boltzmann’s Constant and Avogadro’s Number in Different Units

UNITS AND CONVERSION FACTORS
By: E.J. ROSCHKE

CONVERSION CHARTS
http://www.corr-tech.com/EG_section5.PDF

Conversion tables for units
The table below gives conversion factors from a variety of units to the corresponding SI unit.
Examples of the use of this table have already been given in the preceding section.

Electrical / Instrumentation
Math Formulas and Conversion Factors

Electrical / Instrumentation
Math Formulas and Conversion Factors