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Transmission of Electrical Energy
Fundamentally there are two systems by which electrical energy can be transmitted.
*High voltage DC electrical transmission system.
*High AC electrical transmission system.
There are some advantages in using DC transmission system:
- Only two conductor are required for DC transmission system. It is further possible to use only one conductor of DC transmission system if earth is utilized as return path of the system.The potential stress on the insulator of DC transmission system is about 70 % of same voltage AC transmission system. Hence, less insulation cost is involved in DC transmission system. Inductance, capacitance, phase displacement and surge problems can be eliminated in DC system.
Even having these advantages in DC system, generally electrical energy is transmitted by three(3) phase AC transmission system. The alternating voltages can easily be stepped up and down, which is not possible in DC transmission system. Maintenance of AC substation is quite easy and economical compared to DC. The transforming of power in AC electrical substation is much easier than motor-generator sets in DC system.
But AC transmission system also has some disadvantages like, The volume of conductor used in AC system is much higher than that of DC. The reactance of the line, affects the voltage regulation of electrical power transmission system. Problems of skin effect and proximity effects only found in AC system. AC transmission system is more likely to be affected by corona effect than DC system. Construction of AC electrical power transmission network is more completed than DC system. Proper synchronizing is required before inter connecting two or more transmission lines together, synchronizing can totally be omitted in DC transmission system.
Transmission of Electrical Energy
Fundamentally there are two systems by which electrical energy can be transmitted.
*High voltage DC electrical transmission system.
*High AC electrical transmission system.
There are some advantages in using DC transmission system:
- Only two conductor are required for DC transmission system. It is further possible to use only one conductor of DC transmission system if earth is utilized as return path of the system.The potential stress on the insulator of DC transmission system is about 70 % of same voltage AC transmission system. Hence, less insulation cost is involved in DC transmission system. Inductance, capacitance, phase displacement and surge problems can be eliminated in DC system.
Even having these advantages in DC system, generally electrical energy is transmitted by three(3) phase AC transmission system. The alternating voltages can easily be stepped up and down, which is not possible in DC transmission system. Maintenance of AC substation is quite easy and economical compared to DC. The transforming of power in AC electrical substation is much easier than motor-generator sets in DC system.
But AC transmission system also has some disadvantages like, The volume of conductor used in AC system is much higher than that of DC. The reactance of the line, affects the voltage regulation of electrical power transmission system. Problems of skin effect and proximity effects only found in AC system. AC transmission system is more likely to be affected by corona effect than DC system. Construction of AC electrical power transmission network is more completed than DC system. Proper synchronizing is required before inter connecting two or more transmission lines together, synchronizing can totally be omitted in DC transmission system.
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*_Latest Discoveries and Future Trends_*
1-Dielectric Susceptibility of a Material:
The finding of the dielectric susceptibility has provided enough chances to the engineers to make some ultra-equipped and highly sensitive technological and electronic devices. This discovery is a result of the effect of electric field on a nanostructure of lead zirconate. This specific feature of any material is supposed to be a boon for nanostructures. The importance of this innovation has been widely hailed as it has opened up many doors of making tiny but effective electronic devices.
2- Detection Systems Based on Quantum-entanglement Effect:
Entanglement, a unique feature of quantum physics, is well set to be used in future detection and imaging systems. It is said to be more efficient and accurate than those of many detection system available these days. This mechanism could work spreading entangled beams of light on any object. This could make a very detailed, fair and accurate image of the object being detected. This mechanism is supposed to work on the same principle which is applied to detect planes at airforce stations and airports.
3- Cell-sized Batteries:
These microbatteries could be only half the size of a human cell. Interestingly, these would be made of viruses. This rare innovation is set to provide us a relief from heavy 9-volts batteries and other models. This technology involves the use of microcontact printing. This printing fabricates and position microbattery electrodes. Further, it is probably the first use of virus in this field. These batteries could be used in a series of fields such as computers, cell phones and medical equipments which are implantable.
4- Precise Pattern Micro-chip:
This innovation is supposed to bring microchip technology at its peak. This system works when some molecules are made to assemble themselves into precise patterns. A self-assembling molecular system which is called block copolymers was known for many years. This system was not very effective as it could produce a molecular-orders or patterns in a very limited way via self-assembling. Thus to make it more equipped and advanced, this "limited self-assembly" was made to combine with conventional lithographic chip-making technology. These lithographic patterns cause a tight-hold over self-assembling molecules. Thus they become more structured.
5- High-Power Solar Concentrators:
As the initial research has proved to be fruitful, there are chances that in coming years we will see a sort of solar concentrator, which would be more efficient than the contemporary solar concentrators. The most striking part of this innovation is that it brings huge amount of solar light to the solar cells that too without tracking the sun. Though it showed only 92 percent of stability during the research, it is supposed to guarantee a 100 percent stability till it arrives in the market.
*_Latest Discoveries and Future Trends_*
1-Dielectric Susceptibility of a Material:
The finding of the dielectric susceptibility has provided enough chances to the engineers to make some ultra-equipped and highly sensitive technological and electronic devices. This discovery is a result of the effect of electric field on a nanostructure of lead zirconate. This specific feature of any material is supposed to be a boon for nanostructures. The importance of this innovation has been widely hailed as it has opened up many doors of making tiny but effective electronic devices.
2- Detection Systems Based on Quantum-entanglement Effect:
Entanglement, a unique feature of quantum physics, is well set to be used in future detection and imaging systems. It is said to be more efficient and accurate than those of many detection system available these days. This mechanism could work spreading entangled beams of light on any object. This could make a very detailed, fair and accurate image of the object being detected. This mechanism is supposed to work on the same principle which is applied to detect planes at airforce stations and airports.
3- Cell-sized Batteries:
These microbatteries could be only half the size of a human cell. Interestingly, these would be made of viruses. This rare innovation is set to provide us a relief from heavy 9-volts batteries and other models. This technology involves the use of microcontact printing. This printing fabricates and position microbattery electrodes. Further, it is probably the first use of virus in this field. These batteries could be used in a series of fields such as computers, cell phones and medical equipments which are implantable.
4- Precise Pattern Micro-chip:
This innovation is supposed to bring microchip technology at its peak. This system works when some molecules are made to assemble themselves into precise patterns. A self-assembling molecular system which is called block copolymers was known for many years. This system was not very effective as it could produce a molecular-orders or patterns in a very limited way via self-assembling. Thus to make it more equipped and advanced, this "limited self-assembly" was made to combine with conventional lithographic chip-making technology. These lithographic patterns cause a tight-hold over self-assembling molecules. Thus they become more structured.
5- High-Power Solar Concentrators:
As the initial research has proved to be fruitful, there are chances that in coming years we will see a sort of solar concentrator, which would be more efficient than the contemporary solar concentrators. The most striking part of this innovation is that it brings huge amount of solar light to the solar cells that too without tracking the sun. Though it showed only 92 percent of stability during the research, it is supposed to guarantee a 100 percent stability till it arrives in the market.
@ElectricalLearner®©
*Palm oil insulation could transform old transformers*
Research by a student of University of Leicester has discovered an alternative to a major industrial use of oil. The student has discovered an environment-friendly way to treat palm kernel oil so that it can be used to insulate electrical transformers.
The currently used silicone oils are recognised as having excellent characteristics but they are environmentally unfriendly. The new oil that has been synthesised from Palm Kernel Oil is surprisingly good,environment-friendly, and in many ways appears to be better than the silicone oil .This oil is also cheap in cost than traditional silicone oil and also environment friendly.
*Palm oil insulation could transform old transformers*
Research by a student of University of Leicester has discovered an alternative to a major industrial use of oil. The student has discovered an environment-friendly way to treat palm kernel oil so that it can be used to insulate electrical transformers.
The currently used silicone oils are recognised as having excellent characteristics but they are environmentally unfriendly. The new oil that has been synthesised from Palm Kernel Oil is surprisingly good,environment-friendly, and in many ways appears to be better than the silicone oil .This oil is also cheap in cost than traditional silicone oil and also environment friendly.
How to measure electric current?
Before we know about how to measure electric current, firstly know what is electric current. Electric current is a flow of electric charge, it exist where voltage is present.
To measure electric current we use instrument known as ammeter. If we want to measure electric current, we have to pass the current through through it. However ammeter measure current in ampere. Ampere is the SI unit of current.
However ammeter is not suitable to measure high electric current. In such case we use transformer known as current transformer.
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@mc4eng_books
Before we know about how to measure electric current, firstly know what is electric current. Electric current is a flow of electric charge, it exist where voltage is present.
To measure electric current we use instrument known as ammeter. If we want to measure electric current, we have to pass the current through through it. However ammeter measure current in ampere. Ampere is the SI unit of current.
However ammeter is not suitable to measure high electric current. In such case we use transformer known as current transformer.
📚المكتبة الهندسية📚
@mc4eng_books
Write about Atomic structure and electric change ?
The smallest physically exist particle of an element is molecule. The molecule is made of multiple numbers of atoms. The structure of atom consists of a muscles which is surrounded by numbers of electrons revolve around. The nucleus has highly concentrated protons and neutrons. The nucleus is positively changed as each proton inside it carries positive charge of 1.602 X 10 − 19coulombs. The neutrons inside the nucleus is electrically neutral, means, it does not contain any charge.
Electron has equal and opposite of charge of each proton. That is, net electrical charge of each electron is − 1.602 X 10 − 19 Coulombs. The mass of electron is much lighter than proton; Electron is lighter than a proton by a factor of about 1840.
So, we have seen that proton has positive charge where as electron has negative charge, but an atom is electrically neutral, that implies the number of electrons in the orbits of the atom is exactly equal to the number of proton in nucleus.
There are numbers of orbit present in an atom with different radius. So, some electrons resolve the nucleus from closer some resolve from far. These orbits are called shells or energy levels. This electron in success shells are named as K, L, M, N, O & R. at increase distance outward from nucleus.
Each of these shells has a maximum number of electrons for stability. The maximum number electrons in a filled inner shell can be determined by an easy formula 2n2. Where n is the sequential order of the shell from nucleus. By this formula, the number of electron in first shell of atomic structure is 2, in second shell 8 and in third shell it is 18 and so on. This rule is only applicable to inner shells, not for the outermost shell of atomic structure.
For example, the atomic number of a copper atom is 29. So by applying this formula, we get, the number of electrons in the K, L, M and N are 2, 8, 18 and 1 respectively.
This outermost electron of an atom has least attraction force with nucleus, as the distance from nucleus is highest. So, this can be detached from the parent atom if external energy is supplied. When this loosely bonded electron is detached from the parent atoms, the positive charge of the atoms becomes positive. Then this atom is called an ion. If in a piece of element, these positive ions exist in higher number the element as a whole will have positive electric charge.
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The smallest physically exist particle of an element is molecule. The molecule is made of multiple numbers of atoms. The structure of atom consists of a muscles which is surrounded by numbers of electrons revolve around. The nucleus has highly concentrated protons and neutrons. The nucleus is positively changed as each proton inside it carries positive charge of 1.602 X 10 − 19coulombs. The neutrons inside the nucleus is electrically neutral, means, it does not contain any charge.
Electron has equal and opposite of charge of each proton. That is, net electrical charge of each electron is − 1.602 X 10 − 19 Coulombs. The mass of electron is much lighter than proton; Electron is lighter than a proton by a factor of about 1840.
So, we have seen that proton has positive charge where as electron has negative charge, but an atom is electrically neutral, that implies the number of electrons in the orbits of the atom is exactly equal to the number of proton in nucleus.
There are numbers of orbit present in an atom with different radius. So, some electrons resolve the nucleus from closer some resolve from far. These orbits are called shells or energy levels. This electron in success shells are named as K, L, M, N, O & R. at increase distance outward from nucleus.
Each of these shells has a maximum number of electrons for stability. The maximum number electrons in a filled inner shell can be determined by an easy formula 2n2. Where n is the sequential order of the shell from nucleus. By this formula, the number of electron in first shell of atomic structure is 2, in second shell 8 and in third shell it is 18 and so on. This rule is only applicable to inner shells, not for the outermost shell of atomic structure.
For example, the atomic number of a copper atom is 29. So by applying this formula, we get, the number of electrons in the K, L, M and N are 2, 8, 18 and 1 respectively.
This outermost electron of an atom has least attraction force with nucleus, as the distance from nucleus is highest. So, this can be detached from the parent atom if external energy is supplied. When this loosely bonded electron is detached from the parent atoms, the positive charge of the atoms becomes positive. Then this atom is called an ion. If in a piece of element, these positive ions exist in higher number the element as a whole will have positive electric charge.
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What is the direction of conventional current flow?
In a closed circuit with a voltage source, there should be a flow of positive charges (+) & a flow of negative charges (−) but in opposite direction to each other. The flow of positive charges gives the same electric current, and has the same effect in a circuit, as an equal flow of negative charges in the opposite direction.
Now the interesting fact arises, since current can be the flow of either positive or negative charges, what should be the actual direction of the conventional current flow? The solution of the mystery is the direction of conventional current is defined arbitrarily to be the direction of the flow of positive charges. As the negative charges or electrons flows from the negative terminal (−)to positive terminal(+) of the voltage source, so we can say that conventional current flows on the opposite direction, that is positive terminal(+) to the negative terminal(−) of the same voltage source.
In electrical circuits, most widely used conductors are made of metals like copper & aluminium. But in metals, positive charges are immobile, and the charge carriers are electrons, but we know that electrons carries the negative charges.
So by the above discussion ,we can say that electron motion in a conductor is in the direction opposite to that of conventional (or electric) current. It is a easy & daily application of the conventional current flow theory.
📚المكتبة الهندسية📚
@mc4eng_books
In a closed circuit with a voltage source, there should be a flow of positive charges (+) & a flow of negative charges (−) but in opposite direction to each other. The flow of positive charges gives the same electric current, and has the same effect in a circuit, as an equal flow of negative charges in the opposite direction.
Now the interesting fact arises, since current can be the flow of either positive or negative charges, what should be the actual direction of the conventional current flow? The solution of the mystery is the direction of conventional current is defined arbitrarily to be the direction of the flow of positive charges. As the negative charges or electrons flows from the negative terminal (−)to positive terminal(+) of the voltage source, so we can say that conventional current flows on the opposite direction, that is positive terminal(+) to the negative terminal(−) of the same voltage source.
In electrical circuits, most widely used conductors are made of metals like copper & aluminium. But in metals, positive charges are immobile, and the charge carriers are electrons, but we know that electrons carries the negative charges.
So by the above discussion ,we can say that electron motion in a conductor is in the direction opposite to that of conventional (or electric) current. It is a easy & daily application of the conventional current flow theory.
📚المكتبة الهندسية📚
@mc4eng_books
What is the direction of conventional current flow?
In a closed circuit with a voltage source, there should be a flow of positive charges (+) & a flow of negative charges (−) but in opposite direction to each other. The flow of positive charges gives the same electric current, and has the same effect in a circuit, as an equal flow of negative charges in the opposite direction.
Now the interesting fact arises, since current can be the flow of either positive or negative charges, what should be the actual direction of the conventional current flow? The solution of the mystery is the direction of conventional current is defined arbitrarily to be the direction of the flow of positive charges. As the negative charges or electrons flows from the negative terminal (−)to positive terminal(+) of the voltage source, so we can say that conventional current flows on the opposite direction, that is positive terminal(+) to the negative terminal(−) of the same voltage source.
In electrical circuits, most widely used conductors are made of metals like copper & aluminium. But in metals, positive charges are immobile, and the charge carriers are electrons, but we know that electrons carries the negative charges.
So by the above discussion ,we can say that electron motion in a conductor is in the direction opposite to that of conventional (or electric) current. It is a easy & daily application of the conventional current flow theory.
📚المكتبة الهندسية📚
@mc4eng_books
In a closed circuit with a voltage source, there should be a flow of positive charges (+) & a flow of negative charges (−) but in opposite direction to each other. The flow of positive charges gives the same electric current, and has the same effect in a circuit, as an equal flow of negative charges in the opposite direction.
Now the interesting fact arises, since current can be the flow of either positive or negative charges, what should be the actual direction of the conventional current flow? The solution of the mystery is the direction of conventional current is defined arbitrarily to be the direction of the flow of positive charges. As the negative charges or electrons flows from the negative terminal (−)to positive terminal(+) of the voltage source, so we can say that conventional current flows on the opposite direction, that is positive terminal(+) to the negative terminal(−) of the same voltage source.
In electrical circuits, most widely used conductors are made of metals like copper & aluminium. But in metals, positive charges are immobile, and the charge carriers are electrons, but we know that electrons carries the negative charges.
So by the above discussion ,we can say that electron motion in a conductor is in the direction opposite to that of conventional (or electric) current. It is a easy & daily application of the conventional current flow theory.
📚المكتبة الهندسية📚
@mc4eng_books
What is drift current?
Drift current is the electric current, or movement of charge carriers, which is due to an electric field applied to a circuit, or may be considered as due to a electromotive force over a certain distance. When an electric field that is a potential difference applied across a semiconductor material, the drift current is produced due to flow of charge carriers. The drift velocity is the average velocity of the charge carriers present in the drift current.
If an electric field is applied to an electron (−) existing in a free space, it will accelerate the electron in a straight line from the negative(−) terminal to the positive terminal(+) of the applied voltage source. But the same thing does not happen in the case of electrons available in good conductors ,that is in metals like copper, aluminium etc. Because good conductors have huge numbers of free electrons moving randomly & this random movement of electrons will drift according to the direction of applied electric field and random movement of electrons in a straight line is known as drift current. Drift current also depends on the mobility of charge carriers in the respective conducting medium.
Drift current in a p-n junction diode:
In a p-n junction diode, electrons are the minority charge carriers in the p-region and holes(positive charges) are the minority charge carriers in the n-region. Due to the diffusion of charge carriers, the diffusion current, which flows from the p to n region, is exactly balanced by the equal and opposite drift current. But as minority charge carriers can be thermally generated, drift current is temperature dependent. When an electric field is applied across the semiconductor material, the charge carriers attain a certain drift velocity . This combined effect of movement of the charge carriers constitutes a current known as "drift current". Drift current due to the charge carriers such as free electrons and holes is the current passing through a square centimetre area perpendicular to the direction of flow.
Drift current density, due to free electrons is given by:
Jn = qnE Amp / cm2
Drift current density, due to holes is given by:
Jp = qpE Amp / cm2
n - Number of free electrons per cubic centimetre.
p - Number of holes per cubic centimetre.
E – Applied Electric Field Intensity in V 📚المكتبة الهندسية📚
@mc4eng_books .
q – Charge of an electron = 1.6 × 10−19 coulomb.
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@mc4eng_books
Drift current is the electric current, or movement of charge carriers, which is due to an electric field applied to a circuit, or may be considered as due to a electromotive force over a certain distance. When an electric field that is a potential difference applied across a semiconductor material, the drift current is produced due to flow of charge carriers. The drift velocity is the average velocity of the charge carriers present in the drift current.
If an electric field is applied to an electron (−) existing in a free space, it will accelerate the electron in a straight line from the negative(−) terminal to the positive terminal(+) of the applied voltage source. But the same thing does not happen in the case of electrons available in good conductors ,that is in metals like copper, aluminium etc. Because good conductors have huge numbers of free electrons moving randomly & this random movement of electrons will drift according to the direction of applied electric field and random movement of electrons in a straight line is known as drift current. Drift current also depends on the mobility of charge carriers in the respective conducting medium.
Drift current in a p-n junction diode:
In a p-n junction diode, electrons are the minority charge carriers in the p-region and holes(positive charges) are the minority charge carriers in the n-region. Due to the diffusion of charge carriers, the diffusion current, which flows from the p to n region, is exactly balanced by the equal and opposite drift current. But as minority charge carriers can be thermally generated, drift current is temperature dependent. When an electric field is applied across the semiconductor material, the charge carriers attain a certain drift velocity . This combined effect of movement of the charge carriers constitutes a current known as "drift current". Drift current due to the charge carriers such as free electrons and holes is the current passing through a square centimetre area perpendicular to the direction of flow.
Drift current density, due to free electrons is given by:
Jn = qnE Amp / cm2
Drift current density, due to holes is given by:
Jp = qpE Amp / cm2
n - Number of free electrons per cubic centimetre.
p - Number of holes per cubic centimetre.
E – Applied Electric Field Intensity in V 📚المكتبة الهندسية📚
@mc4eng_books .
q – Charge of an electron = 1.6 × 10−19 coulomb.
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@mc4eng_books
What is the nature of electricity?
All matters consists of minute particles called molecules which are themselves made up still minute particles known as atoms. An atom has a hard central core known as nucleus. It consists of protons and neutrons. The protons are positively charged and neutrons are electrically neutral. Electrons revolve round the nucleus, in orbits. The number of electrons and protons in an atom is same hence an atom is as a whole is electrically neutral. The centripetal force necessary to keep electrons rotating round the nucleus is supplied by the force of attraction between nucleus and electrons. It is obvious that this force becomes weaker as the distance of the electrons from nucleus increases. It is found that in metals the outermost electrons are very loosely attached to the atom. In fact they can be hardly said to be attached to one parent atom, they very freely move from one atom to another in random manner.
If a potential difference is applied across a metallic conductor, due to electric field, the electrons experience an attractive force towards higher potential or positive terminal of the conductor. As a result the free electrons start drifting from negative terminal to positive terminal of the conductor. This continuous flow of electrons constitute an electric current. This is answer of your question what is the nature of electricity ?.
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All matters consists of minute particles called molecules which are themselves made up still minute particles known as atoms. An atom has a hard central core known as nucleus. It consists of protons and neutrons. The protons are positively charged and neutrons are electrically neutral. Electrons revolve round the nucleus, in orbits. The number of electrons and protons in an atom is same hence an atom is as a whole is electrically neutral. The centripetal force necessary to keep electrons rotating round the nucleus is supplied by the force of attraction between nucleus and electrons. It is obvious that this force becomes weaker as the distance of the electrons from nucleus increases. It is found that in metals the outermost electrons are very loosely attached to the atom. In fact they can be hardly said to be attached to one parent atom, they very freely move from one atom to another in random manner.
If a potential difference is applied across a metallic conductor, due to electric field, the electrons experience an attractive force towards higher potential or positive terminal of the conductor. As a result the free electrons start drifting from negative terminal to positive terminal of the conductor. This continuous flow of electrons constitute an electric current. This is answer of your question what is the nature of electricity ?.
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Proper definition of electric current?
Actually, before coming to the question that what is electric current, we need to know what is electricity. Now in some easier words, electricity can be defined as the movement of free electrons across any materials. The outer electrons of an atom is loosely attached with the nucleus, so not much energy is required to de touch this loosely bond electrons from the atom. So when the excitation is provided properly, this electrons get detached from the atom. As well as when these electrons collide with other loosely bond electrons, ultimately the no. of free electrons increases in the matter. And finally when this electrons flow from higher potential to lower potential, we can term that flow as electric current, which flows through the conductor. Now measurement of electric current is done on the basis of the charge of electrons because current is nothing but flow of electrons from higher potential to lower potential.
Now, as charge of an electron is = − 1.6021 × 10− 19coulomb. So, the unit of electric current is expressed as coulomb/sec. Because, this term defines the no. of electrons flowing through a cross section of the conductor. Now coulomb/second is termed as Ampere(A). So the SI unit of electric current flow is Ampere(A).
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@mc4eng_books
Actually, before coming to the question that what is electric current, we need to know what is electricity. Now in some easier words, electricity can be defined as the movement of free electrons across any materials. The outer electrons of an atom is loosely attached with the nucleus, so not much energy is required to de touch this loosely bond electrons from the atom. So when the excitation is provided properly, this electrons get detached from the atom. As well as when these electrons collide with other loosely bond electrons, ultimately the no. of free electrons increases in the matter. And finally when this electrons flow from higher potential to lower potential, we can term that flow as electric current, which flows through the conductor. Now measurement of electric current is done on the basis of the charge of electrons because current is nothing but flow of electrons from higher potential to lower potential.
Now, as charge of an electron is = − 1.6021 × 10− 19coulomb. So, the unit of electric current is expressed as coulomb/sec. Because, this term defines the no. of electrons flowing through a cross section of the conductor. Now coulomb/second is termed as Ampere(A). So the SI unit of electric current flow is Ampere(A).
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Common Electrical Units
Ampere - A
An ampere is the current which - if maintained in two straight parallel conductors of infinite length - of negligible circular cross section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 2 x 10-7 Newton per meter of length.
Electric current is the same as electric quantity in movement, or quantity per unit time:
I = Q / t (1)
where
I = electric current (ampere, A)
Q = electric quantity (coulomb, C)
t = time (s)
1 ampere = 1 coulomb per sec.
Ampere can be measured with an "ammeter" in series with the electric circuit.
Coulomb - C
The standard unit of quantity in electrical measurements. It is the quantity of electricity conveyed in one second by the current produced by an electro-motive force of one volt acting in a circuit having a resistance of one ohm, or the quantity transferred by one ampere in one second.
Q = I t (2)
1 coulomb = 6.24 1018 electrons
Farad - F
The farad is the standard unit of capacitance. Reduced to base SI units one farad is the equivalent of one second to the fourth power ampere squared per kilogram per meter squared (s4 A2/kg m2).
When the voltage across a 1 F capacitor changes at a rate of one volt per second (1 V/s) a current flow of 1 A results. A capacitance of 1 F produces 1 Vof potential difference for an electric charge of one coulomb (1 C).
In common electrical and electronic circuits units of microfarads μF (1 μF = 10-6 F) and picofarads pF (1 pF = 10-12 F) are used.
Ohm - Ω
The derived SI unit of electrical resistance - the resistance between two points on a conductor when a constant potential difference of 1 volt between them produces a current of 1 ampere.
Henry - H
The Henry is the unit of inductance. Reduced to base SI units one henry is the equivalent of one kilogram meter squared per second squared per ampere squared (kg m2 s-2 A-2).
Inductance
An inductor is a passive electronic component that stores energy in the form of a magnetic field.
The standard unit of inductance is the henry abbreviated H. This is a large unit and more commonly used units are the microhenry abbreviated μH (1 μH =10-6H) and the millihenry abbreviated mH (1 mH =10-3 H). Occasionally, the nanohenry abbreviated nH (1 nH = 10-9 H) is used.
Joule - J
The unit of energy work or quantity of heat done when a force of one Newton is applied over a displacement of one meter. One joule is the equivalent of one watt of power radiated or dissipated for one second.
In imperial units the British Thermal Unit (Btu) is used to express energy. One Btu is equivalent to approximately 1,055 joules.
Siemens - S
The unit of electrical conductance S = A / V
Watt
The watt is used to specify the rate at which electrical energy is dissipated, or the rate at which electromagnetic energy is radiated, absorbed, or dissipated.
The unit of power W or Joule/second
Weber - Wb
The unit of magnetic flux.
The flux that when linking a circuit of one turn, produces an Electro Motive Force - EMF - of 1 volt as it is reduced to zero at a uniform rate in one second.
1 Weber is equivalent to 108 Maxwells
Tesla - T
The unit of magnetic flux density the Tesla is equal to 1 Weber per square meter of circuit area.
Volt
The Volt - V - is the Standard International (SI) unit of electric potential or electromotive force. A potential of one volt appears across a resistance of one ohm when a current of one ampere flows through that resistance.
Reduced to SI base units,
1 (V) = 1 (kg m2 / s3 A)
A "voltmeter" can be used to measure voltage and mus be connected in parallel with the part of the circuit whose voltage is required.
Ampere - A
An ampere is the current which - if maintained in two straight parallel conductors of infinite length - of negligible circular cross section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 2 x 10-7 Newton per meter of length.
Electric current is the same as electric quantity in movement, or quantity per unit time:
I = Q / t (1)
where
I = electric current (ampere, A)
Q = electric quantity (coulomb, C)
t = time (s)
1 ampere = 1 coulomb per sec.
Ampere can be measured with an "ammeter" in series with the electric circuit.
Coulomb - C
The standard unit of quantity in electrical measurements. It is the quantity of electricity conveyed in one second by the current produced by an electro-motive force of one volt acting in a circuit having a resistance of one ohm, or the quantity transferred by one ampere in one second.
Q = I t (2)
1 coulomb = 6.24 1018 electrons
Farad - F
The farad is the standard unit of capacitance. Reduced to base SI units one farad is the equivalent of one second to the fourth power ampere squared per kilogram per meter squared (s4 A2/kg m2).
When the voltage across a 1 F capacitor changes at a rate of one volt per second (1 V/s) a current flow of 1 A results. A capacitance of 1 F produces 1 Vof potential difference for an electric charge of one coulomb (1 C).
In common electrical and electronic circuits units of microfarads μF (1 μF = 10-6 F) and picofarads pF (1 pF = 10-12 F) are used.
Ohm - Ω
The derived SI unit of electrical resistance - the resistance between two points on a conductor when a constant potential difference of 1 volt between them produces a current of 1 ampere.
Henry - H
The Henry is the unit of inductance. Reduced to base SI units one henry is the equivalent of one kilogram meter squared per second squared per ampere squared (kg m2 s-2 A-2).
Inductance
An inductor is a passive electronic component that stores energy in the form of a magnetic field.
The standard unit of inductance is the henry abbreviated H. This is a large unit and more commonly used units are the microhenry abbreviated μH (1 μH =10-6H) and the millihenry abbreviated mH (1 mH =10-3 H). Occasionally, the nanohenry abbreviated nH (1 nH = 10-9 H) is used.
Joule - J
The unit of energy work or quantity of heat done when a force of one Newton is applied over a displacement of one meter. One joule is the equivalent of one watt of power radiated or dissipated for one second.
In imperial units the British Thermal Unit (Btu) is used to express energy. One Btu is equivalent to approximately 1,055 joules.
Siemens - S
The unit of electrical conductance S = A / V
Watt
The watt is used to specify the rate at which electrical energy is dissipated, or the rate at which electromagnetic energy is radiated, absorbed, or dissipated.
The unit of power W or Joule/second
Weber - Wb
The unit of magnetic flux.
The flux that when linking a circuit of one turn, produces an Electro Motive Force - EMF - of 1 volt as it is reduced to zero at a uniform rate in one second.
1 Weber is equivalent to 108 Maxwells
Tesla - T
The unit of magnetic flux density the Tesla is equal to 1 Weber per square meter of circuit area.
Volt
The Volt - V - is the Standard International (SI) unit of electric potential or electromotive force. A potential of one volt appears across a resistance of one ohm when a current of one ampere flows through that resistance.
Reduced to SI base units,
1 (V) = 1 (kg m2 / s3 A)
A "voltmeter" can be used to measure voltage and mus be connected in parallel with the part of the circuit whose voltage is required.
®©
Transmission of Electrical Energy
Fundamentally there are two systems by which electrical energy can be transmitted.
*High voltage DC electrical transmission system.
*High AC electrical transmission system.
There are some advantages in using DC transmission system:
- Only two conductor are required for DC transmission system. It is further possible to use only one conductor of DC transmission system if earth is utilized as return path of the system.The potential stress on the insulator of DC transmission system is about 70 % of same voltage AC transmission system. Hence, less insulation cost is involved in DC transmission system. Inductance, capacitance, phase displacement and surge problems can be eliminated in DC system.
Even having these advantages in DC system, generally electrical energy is transmitted by three(3) phase AC transmission system. The alternating voltages can easily be stepped up and down, which is not possible in DC transmission system. Maintenance of AC substation is quite easy and economical compared to DC. The transforming of power in AC electrical substation is much easier than motor-generator sets in DC system.
But AC transmission system also has some disadvantages like, The volume of conductor used in AC system is much higher than that of DC. The reactance of the line, affects the voltage regulation of electrical power transmission system. Problems of skin effect and proximity effects only found in AC system. AC transmission system is more likely to be affected by corona effect than DC system. Construction of AC electrical power transmission network is more completed than DC system. Proper synchronizing is required before inter connecting two or more transmission lines together, synchronizing can totally be omitted in DC transmission system.
------------------------------
#كهرباء #اتصالات #ميكانيك #it
@mc4eng_2
Transmission of Electrical Energy
Fundamentally there are two systems by which electrical energy can be transmitted.
*High voltage DC electrical transmission system.
*High AC electrical transmission system.
There are some advantages in using DC transmission system:
- Only two conductor are required for DC transmission system. It is further possible to use only one conductor of DC transmission system if earth is utilized as return path of the system.The potential stress on the insulator of DC transmission system is about 70 % of same voltage AC transmission system. Hence, less insulation cost is involved in DC transmission system. Inductance, capacitance, phase displacement and surge problems can be eliminated in DC system.
Even having these advantages in DC system, generally electrical energy is transmitted by three(3) phase AC transmission system. The alternating voltages can easily be stepped up and down, which is not possible in DC transmission system. Maintenance of AC substation is quite easy and economical compared to DC. The transforming of power in AC electrical substation is much easier than motor-generator sets in DC system.
But AC transmission system also has some disadvantages like, The volume of conductor used in AC system is much higher than that of DC. The reactance of the line, affects the voltage regulation of electrical power transmission system. Problems of skin effect and proximity effects only found in AC system. AC transmission system is more likely to be affected by corona effect than DC system. Construction of AC electrical power transmission network is more completed than DC system. Proper synchronizing is required before inter connecting two or more transmission lines together, synchronizing can totally be omitted in DC transmission system.
------------------------------
#كهرباء #اتصالات #ميكانيك #it
@mc4eng_2
®©
*_Latest Discoveries and Future Trends_*
1-Dielectric Susceptibility of a Material:
The finding of the dielectric susceptibility has provided enough chances to the engineers to make some ultra-equipped and highly sensitive technological and electronic devices. This discovery is a result of the effect of electric field on a nanostructure of lead zirconate. This specific feature of any material is supposed to be a boon for nanostructures. The importance of this innovation has been widely hailed as it has opened up many doors of making tiny but effective electronic devices.
2- Detection Systems Based on Quantum-entanglement Effect:
Entanglement, a unique feature of quantum physics, is well set to be used in future detection and imaging systems. It is said to be more efficient and accurate than those of many detection system available these days. This mechanism could work spreading entangled beams of light on any object. This could make a very detailed, fair and accurate image of the object being detected. This mechanism is supposed to work on the same principle which is applied to detect planes at airforce stations and airports.
3- Cell-sized Batteries:
These microbatteries could be only half the size of a human cell. Interestingly, these would be made of viruses. This rare innovation is set to provide us a relief from heavy 9-volts batteries and other models. This technology involves the use of microcontact printing. This printing fabricates and position microbattery electrodes. Further, it is probably the first use of virus in this field. These batteries could be used in a series of fields such as computers, cell phones and medical equipments which are implantable.
4- Precise Pattern Micro-chip:
This innovation is supposed to bring microchip technology at its peak. This system works when some molecules are made to assemble themselves into precise patterns. A self-assembling molecular system which is called block copolymers was known for many years. This system was not very effective as it could produce a molecular-orders or patterns in a very limited way via self-assembling. Thus to make it more equipped and advanced, this "limited self-assembly" was made to combine with conventional lithographic chip-making technology. These lithographic patterns cause a tight-hold over self-assembling molecules. Thus they become more structured.
5- High-Power Solar Concentrators:
As the initial research has proved to be fruitful, there are chances that in coming years we will see a sort of solar concentrator, which would be more efficient than the contemporary solar concentrators. The most striking part of this innovation is that it brings huge amount of solar light to the solar cells that too without tracking the sun. Though it showed only 92 percent of stability during the research, it is supposed to guarantee a 100 percent stability till it arrives in the market.
------------------------------
#كهرباء #اتصالات #ميكانيك #it
@mc4eng_2
*_Latest Discoveries and Future Trends_*
1-Dielectric Susceptibility of a Material:
The finding of the dielectric susceptibility has provided enough chances to the engineers to make some ultra-equipped and highly sensitive technological and electronic devices. This discovery is a result of the effect of electric field on a nanostructure of lead zirconate. This specific feature of any material is supposed to be a boon for nanostructures. The importance of this innovation has been widely hailed as it has opened up many doors of making tiny but effective electronic devices.
2- Detection Systems Based on Quantum-entanglement Effect:
Entanglement, a unique feature of quantum physics, is well set to be used in future detection and imaging systems. It is said to be more efficient and accurate than those of many detection system available these days. This mechanism could work spreading entangled beams of light on any object. This could make a very detailed, fair and accurate image of the object being detected. This mechanism is supposed to work on the same principle which is applied to detect planes at airforce stations and airports.
3- Cell-sized Batteries:
These microbatteries could be only half the size of a human cell. Interestingly, these would be made of viruses. This rare innovation is set to provide us a relief from heavy 9-volts batteries and other models. This technology involves the use of microcontact printing. This printing fabricates and position microbattery electrodes. Further, it is probably the first use of virus in this field. These batteries could be used in a series of fields such as computers, cell phones and medical equipments which are implantable.
4- Precise Pattern Micro-chip:
This innovation is supposed to bring microchip technology at its peak. This system works when some molecules are made to assemble themselves into precise patterns. A self-assembling molecular system which is called block copolymers was known for many years. This system was not very effective as it could produce a molecular-orders or patterns in a very limited way via self-assembling. Thus to make it more equipped and advanced, this "limited self-assembly" was made to combine with conventional lithographic chip-making technology. These lithographic patterns cause a tight-hold over self-assembling molecules. Thus they become more structured.
5- High-Power Solar Concentrators:
As the initial research has proved to be fruitful, there are chances that in coming years we will see a sort of solar concentrator, which would be more efficient than the contemporary solar concentrators. The most striking part of this innovation is that it brings huge amount of solar light to the solar cells that too without tracking the sun. Though it showed only 92 percent of stability during the research, it is supposed to guarantee a 100 percent stability till it arrives in the market.
------------------------------
#كهرباء #اتصالات #ميكانيك #it
@mc4eng_2
®©
*Palm oil insulation could transform old transformers*
Research by a student of University of Leicester has discovered an alternative to a major industrial use of oil. The student has discovered an environment-friendly way to treat palm kernel oil so that it can be used to insulate electrical transformers.
The currently used silicone oils are recognised as having excellent characteristics but they are environmentally unfriendly. The new oil that has been synthesised from Palm Kernel Oil is surprisingly good,environment-friendly, and in many ways appears to be better than the silicone oil .This oil is also cheap in cost than traditional silicone oil and also environment friendly.
------------------------------
#كهرباء #اتصالات #ميكانيك #it
@mc4eng_2
*Palm oil insulation could transform old transformers*
Research by a student of University of Leicester has discovered an alternative to a major industrial use of oil. The student has discovered an environment-friendly way to treat palm kernel oil so that it can be used to insulate electrical transformers.
The currently used silicone oils are recognised as having excellent characteristics but they are environmentally unfriendly. The new oil that has been synthesised from Palm Kernel Oil is surprisingly good,environment-friendly, and in many ways appears to be better than the silicone oil .This oil is also cheap in cost than traditional silicone oil and also environment friendly.
------------------------------
#كهرباء #اتصالات #ميكانيك #it
@mc4eng_2
Volt - unit of electrical potential or motive force - potential is required to send one ampere of current through one ohm of resistance
Ohm - unit of resistance - one ohm is the resistance offered to the passage of one ampere when impelled by one volt
Ampere - units of current - one ampere is the current which one volt can send through a resistance of one ohm
Watt - unit of electrical energy or power - one watt is the product of one ampere and one volt - one ampere of current flowing under the force of one volt gives one watt of energy
Volt-ampere (VA) - is a measurement of power in a direct current ( DC ) electrical circuit. The VA specification is also used in alternating current ( AC ) circuits, but it is less precise in this application, because it represents apparent power , which often differs from true power .
Kilovolt Ampere - one kilovolt ampere - KVA - is equal to 1000 volt amperes
Power Factor - ratio of watts to volt amperes
Most important Formulas:
Voltage V = I × R = P / I = √(P × R) in volts V
Current I = V / R = P / V = √(P / R) in amperes A
Resistance R = V / I = P / I2 = V2 / P in ohms Ω
Power P = V × I = R × I2 = V2 / R in watts W

Electrical Potential - Ohm's Law
Ohm's law can be expressed as:
V = R I (1a)
V = P / I (1b)
V = (P R)1/2 (1c)
Electric Current - Ohm's Law
I = V / R (2a)
I = P / V (2b)
I = (P / R)1/2 (2c)
Electric Resistance - Ohm's Law
R = V / I (3a)
R = V2/ P (3b)
R = P / I2 (3c)
Electric Power
P = V I (4a)
P = R I2 (4b)
P = V2/ R (4c)
where
P = power (watts, W), V = voltage (volts, V)
I = current (amperes, A), R = resistance (ohms, Ω)
Electric Energy :Electric energy is power multiplied time, or
W = P t (5)
where
W = energy (Ws, J), t = time (s)
Electrical Motors : Electrical Motor Efficiency
μ = 746 Php / Pinput_w (6)
where
μ = efficiency
Php = output horsepower (hp)
Pinput_w = input electrical power (watts)
or alternatively
μ = 746 Php / (1.732 V I PF) (6b)
Electrical Motor - Power
P3-phase = (V I PF 1.732) / 1,000 (7)
where
P3-phase = electrical power 3-phase motor (kW)
PF = power factor electrical motor
Electrical Motor - Amps
I3-phase = (746 Php) / (1.732 V μ PF) (7)
where
I3-phase = electrical current 3-phase motor (amps)
PF = power factor electrical motor
Electrical measurements
Quantity
Name
Definition
frequency f
hertz (Hz)
1/s
force F
newton (N)
kg•m/s²
pressure p
pascal (Pa) = N/m²
kg/m•s²
energy E
work joule (J) = N•m
kg•m²/s²
power P
watt (W) = J/s
kg•m²/s³
electric charge Q
coulomb (C) = A•s
A•s
voltage V
volt (V)= W/A
kg•m²/A•s³
current I
ampere (A) = Q/s
A
capacitance C
farad (F) = C/V = A•s/V = s/Ω
A²•s4/kg•m²
Volt - unit of electrical potential or motive force - potential is required to send one ampere of current through one ohm of resistance
Ohm - unit of resistance - one ohm is the resistance offered to the passage of one ampere when impelled by one volt
Ampere - units of current - one ampere is the current which one volt can send through a resistance of one ohm
Watt - unit of electrical energy or power - one watt is the product of one ampere and one volt - one ampere of current flowing under the force of one volt gives one watt of energy
Volt-ampere (VA) - is a measurement of power in a direct current ( DC ) electrical circuit. The VA specification is also used in alternating current ( AC ) circuits, but it is less precise in this application, because it represents apparent power , which often differs from true power .
Kilovolt Ampere - one kilovolt ampere - KVA - is equal to 1000 volt amperes
Power Factor - ratio of watts to volt amperes
Most important Formulas:
Voltage V = I × R = P / I = √(P × R) in volts V
Current I = V / R = P / V = √(P / R)
Ohm - unit of resistance - one ohm is the resistance offered to the passage of one ampere when impelled by one volt
Ampere - units of current - one ampere is the current which one volt can send through a resistance of one ohm
Watt - unit of electrical energy or power - one watt is the product of one ampere and one volt - one ampere of current flowing under the force of one volt gives one watt of energy
Volt-ampere (VA) - is a measurement of power in a direct current ( DC ) electrical circuit. The VA specification is also used in alternating current ( AC ) circuits, but it is less precise in this application, because it represents apparent power , which often differs from true power .
Kilovolt Ampere - one kilovolt ampere - KVA - is equal to 1000 volt amperes
Power Factor - ratio of watts to volt amperes
Most important Formulas:
Voltage V = I × R = P / I = √(P × R) in volts V
Current I = V / R = P / V = √(P / R) in amperes A
Resistance R = V / I = P / I2 = V2 / P in ohms Ω
Power P = V × I = R × I2 = V2 / R in watts W

Electrical Potential - Ohm's Law
Ohm's law can be expressed as:
V = R I (1a)
V = P / I (1b)
V = (P R)1/2 (1c)
Electric Current - Ohm's Law
I = V / R (2a)
I = P / V (2b)
I = (P / R)1/2 (2c)
Electric Resistance - Ohm's Law
R = V / I (3a)
R = V2/ P (3b)
R = P / I2 (3c)
Electric Power
P = V I (4a)
P = R I2 (4b)
P = V2/ R (4c)
where
P = power (watts, W), V = voltage (volts, V)
I = current (amperes, A), R = resistance (ohms, Ω)
Electric Energy :Electric energy is power multiplied time, or
W = P t (5)
where
W = energy (Ws, J), t = time (s)
Electrical Motors : Electrical Motor Efficiency
μ = 746 Php / Pinput_w (6)
where
μ = efficiency
Php = output horsepower (hp)
Pinput_w = input electrical power (watts)
or alternatively
μ = 746 Php / (1.732 V I PF) (6b)
Electrical Motor - Power
P3-phase = (V I PF 1.732) / 1,000 (7)
where
P3-phase = electrical power 3-phase motor (kW)
PF = power factor electrical motor
Electrical Motor - Amps
I3-phase = (746 Php) / (1.732 V μ PF) (7)
where
I3-phase = electrical current 3-phase motor (amps)
PF = power factor electrical motor
Electrical measurements
Quantity
Name
Definition
frequency f
hertz (Hz)
1/s
force F
newton (N)
kg•m/s²
pressure p
pascal (Pa) = N/m²
kg/m•s²
energy E
work joule (J) = N•m
kg•m²/s²
power P
watt (W) = J/s
kg•m²/s³
electric charge Q
coulomb (C) = A•s
A•s
voltage V
volt (V)= W/A
kg•m²/A•s³
current I
ampere (A) = Q/s
A
capacitance C
farad (F) = C/V = A•s/V = s/Ω
A²•s4/kg•m²
Volt - unit of electrical potential or motive force - potential is required to send one ampere of current through one ohm of resistance
Ohm - unit of resistance - one ohm is the resistance offered to the passage of one ampere when impelled by one volt
Ampere - units of current - one ampere is the current which one volt can send through a resistance of one ohm
Watt - unit of electrical energy or power - one watt is the product of one ampere and one volt - one ampere of current flowing under the force of one volt gives one watt of energy
Volt-ampere (VA) - is a measurement of power in a direct current ( DC ) electrical circuit. The VA specification is also used in alternating current ( AC ) circuits, but it is less precise in this application, because it represents apparent power , which often differs from true power .
Kilovolt Ampere - one kilovolt ampere - KVA - is equal to 1000 volt amperes
Power Factor - ratio of watts to volt amperes
Most important Formulas:
Voltage V = I × R = P / I = √(P × R) in volts V
Current I = V / R = P / V = √(P / R)
in amperes A
Resistance R = V / I = P / I2 = V2 / P in ohms Ω
Power P = V × I = R × I2 = V2 / R in watts W

Electrical Potential - Ohm's Law
Ohm's law can be expressed as:
V = R I (1a)
V = P / I (1b)
V = (P R)1/2 (1c)
Electric Current - Ohm's Law
I = V / R (2a)
I = P / V (2b)
I = (P / R)1/2 (2c)
Electric Resistance - Ohm's Law
R = V / I (3a)
R = V2/ P (3b)
R = P / I2 (3c)
Electric Power
P = V I (4a)
P = R I2 (4b)
P = V2/ R (4c)
where
P = power (watts, W), V = voltage (volts, V)
I = current (amperes, A), R = resistance (ohms, Ω)
Electric Energy :Electric energy is power multiplied time, or
W = P t (5)
where
W = energy (Ws, J), t = time (s)
Electrical Motors : Electrical Motor Efficiency
μ = 746 Php / Pinput_w (6)
where
μ = efficiency
Php = output horsepower (hp)
Pinput_w = input electrical power (watts)
or alternatively
μ = 746 Php / (1.732 V I PF) (6b)
Electrical Motor - Power
P3-phase = (V I PF 1.732) / 1,000 (7)
where
P3-phase = electrical power 3-phase motor (kW)
PF = power factor electrical motor
Electrical Motor - Amps
I3-phase = (746 Php) / (1.732 V μ PF) (7)
where
I3-phase = electrical current 3-phase motor (amps)
PF = power factor electrical motor
Electrical measurements
Quantity
Name
Definition
frequency f
hertz (Hz)
1/s
force F
newton (N)
kg•m/s²
pressure p
pascal (Pa) = N/m²
kg/m•s²
energy E
work joule (J) = N•m
kg•m²/s²
power P
watt (W) = J/s
kg•m²/s³
electric charge Q
coulomb (C) = A•s
A•s
voltage V
volt (V)= W/A
kg•m²/A•s³
current I
ampere (A) = Q/s
A
capacitance C
farad (F) = C/V = A•s/V = s/Ω
A²•s4/kg•m²
Resistance R = V / I = P / I2 = V2 / P in ohms Ω
Power P = V × I = R × I2 = V2 / R in watts W

Electrical Potential - Ohm's Law
Ohm's law can be expressed as:
V = R I (1a)
V = P / I (1b)
V = (P R)1/2 (1c)
Electric Current - Ohm's Law
I = V / R (2a)
I = P / V (2b)
I = (P / R)1/2 (2c)
Electric Resistance - Ohm's Law
R = V / I (3a)
R = V2/ P (3b)
R = P / I2 (3c)
Electric Power
P = V I (4a)
P = R I2 (4b)
P = V2/ R (4c)
where
P = power (watts, W), V = voltage (volts, V)
I = current (amperes, A), R = resistance (ohms, Ω)
Electric Energy :Electric energy is power multiplied time, or
W = P t (5)
where
W = energy (Ws, J), t = time (s)
Electrical Motors : Electrical Motor Efficiency
μ = 746 Php / Pinput_w (6)
where
μ = efficiency
Php = output horsepower (hp)
Pinput_w = input electrical power (watts)
or alternatively
μ = 746 Php / (1.732 V I PF) (6b)
Electrical Motor - Power
P3-phase = (V I PF 1.732) / 1,000 (7)
where
P3-phase = electrical power 3-phase motor (kW)
PF = power factor electrical motor
Electrical Motor - Amps
I3-phase = (746 Php) / (1.732 V μ PF) (7)
where
I3-phase = electrical current 3-phase motor (amps)
PF = power factor electrical motor
Electrical measurements
Quantity
Name
Definition
frequency f
hertz (Hz)
1/s
force F
newton (N)
kg•m/s²
pressure p
pascal (Pa) = N/m²
kg/m•s²
energy E
work joule (J) = N•m
kg•m²/s²
power P
watt (W) = J/s
kg•m²/s³
electric charge Q
coulomb (C) = A•s
A•s
voltage V
volt (V)= W/A
kg•m²/A•s³
current I
ampere (A) = Q/s
A
capacitance C
farad (F) = C/V = A•s/V = s/Ω
A²•s4/kg•m²
Power Factor Correction Equipment: advantages and disadvantages
Normally, the power factor of the whole load on a large generating station is in the region of 0•8 to 0•9. However, sometimes it is lower and in such cases it is generally desirable to take special steps to improve the power factor. This can be achieved by the following equipment:
Static capacitor
The power factor can be improved by connecting capacitors in parallel with the equipment operating at lagging power factor. The capacitor (generally known as static capacitor) draws a leading current and partly or completely neutralizes the lagging reactive component of load current. This raises the power factor of the load. For three-phase loads, the capacitors can be connected in delta or star.
Advantages
They have low losses
They require little maintenance as there are no rotating parts
They can be easily installed as they are light and require no foundation
They can work under ordinary atmospheric conditions
Disadvantages
They have short service life ranging from 8 to 10 years
They are easily damaged if the voltage exceeds the rated value
Once the capacitors are damaged, their repair is uneconomical
Synchronous condenser
A synchronous motor takes a leading current when over-excited and, therefore, behaves as a capacitor. An over-excited synchronous motor running on no load is known as synchronous condenser. When such a machine is connected in parallel with the supply, it takes a leading current which partly neutralizes the lagging reactive component of the load. Thus the power factor is improved.
Advantages
By varying the field excitation, the magnitude of current drawn by the motor can be changed
by any amount. This helps in achieving step less †control of power factor
The motor windings have high thermal stability to short circuit currents
The faults can be removed easily
Disadvantages
There are considerable losses in the motor
The maintenance cost is high
It produces noise
Except in sizes above 500 kVA, the cost is greater than that of static capacitors of the same
rating
As a synchronous motor has no self-starting torque, therefore, an auxiliary equipment has to
be provided for this purpose
Phase advancers
Phase advancers are used to improve the power factor of induction motors. The low power factor of an induction motor is due to the fact that its stator winding draws exciting current which lags be-hind the supply voltage by 90 degrees. If the exciting ampere turns can be provided from some other a.c. source, then the stator winding will be relieved of exciting current and the power factor of the motor can be improved. This job is accomplished by the phase advancer which is simply an a.c. exciter. The phase advancer is mounted on the same shaft as the main motor and is connected in the rotor circuit of the motor. It provides exciting ampere turns to the rotor circuit at slip frequency. By providing more ampere turns than required, the induction motor can be made to operate on leading power factor like an over-excited synchronous motor.
Advantages
As the exciting ampere turns are sup-plied at slip frequency, therefore, lagging kVAR drawn by the motor are considerably reduced
The phase advancer can be conveniently used where the use of synchronous motors is inadmissible
However, the major disadvantage of phase advancers is that they are not economical for motors below 200 H.P
Normally, the power factor of the whole load on a large generating station is in the region of 0•8 to 0•9. However, sometimes it is lower and in such cases it is generally desirable to take special steps to improve the power factor. This can be achieved by the following equipment:
Static capacitor
The power factor can be improved by connecting capacitors in parallel with the equipment operating at lagging power factor. The capacitor (generally known as static capacitor) draws a leading current and partly or completely neutralizes the lagging reactive component of load current. This raises the power factor of the load. For three-phase loads, the capacitors can be connected in delta or star.
Advantages
They have low losses
They require little maintenance as there are no rotating parts
They can be easily installed as they are light and require no foundation
They can work under ordinary atmospheric conditions
Disadvantages
They have short service life ranging from 8 to 10 years
They are easily damaged if the voltage exceeds the rated value
Once the capacitors are damaged, their repair is uneconomical
Synchronous condenser
A synchronous motor takes a leading current when over-excited and, therefore, behaves as a capacitor. An over-excited synchronous motor running on no load is known as synchronous condenser. When such a machine is connected in parallel with the supply, it takes a leading current which partly neutralizes the lagging reactive component of the load. Thus the power factor is improved.
Advantages
By varying the field excitation, the magnitude of current drawn by the motor can be changed
by any amount. This helps in achieving step less †control of power factor
The motor windings have high thermal stability to short circuit currents
The faults can be removed easily
Disadvantages
There are considerable losses in the motor
The maintenance cost is high
It produces noise
Except in sizes above 500 kVA, the cost is greater than that of static capacitors of the same
rating
As a synchronous motor has no self-starting torque, therefore, an auxiliary equipment has to
be provided for this purpose
Phase advancers
Phase advancers are used to improve the power factor of induction motors. The low power factor of an induction motor is due to the fact that its stator winding draws exciting current which lags be-hind the supply voltage by 90 degrees. If the exciting ampere turns can be provided from some other a.c. source, then the stator winding will be relieved of exciting current and the power factor of the motor can be improved. This job is accomplished by the phase advancer which is simply an a.c. exciter. The phase advancer is mounted on the same shaft as the main motor and is connected in the rotor circuit of the motor. It provides exciting ampere turns to the rotor circuit at slip frequency. By providing more ampere turns than required, the induction motor can be made to operate on leading power factor like an over-excited synchronous motor.
Advantages
As the exciting ampere turns are sup-plied at slip frequency, therefore, lagging kVAR drawn by the motor are considerably reduced
The phase advancer can be conveniently used where the use of synchronous motors is inadmissible
However, the major disadvantage of phase advancers is that they are not economical for motors below 200 H.P
Forwarded from الدلال
العرض الاقوى
للتجار والمستثمرين
فرصة لا تفوت
في وسط العاصمة صنعاء
في باب اليمن
بيت شعبي في شارع الدفاع
المساحة: 12 لبنة، الارض حر
الواجهة 20 متر على الشارع نفسه مع مدخل الى السايلة امام مجمع العرضي بباب اليمن
شارع 18 متر
بيت لورثه ويشتوا يبيعوا
البصائر والاوراق موجودة
ومضمون ومافي اي مشاكل عليه
سعر اللبنة 25 مليون قابل للتفاوض
للتواصل : 770606013
للتجار والمستثمرين
فرصة لا تفوت
في وسط العاصمة صنعاء
في باب اليمن
بيت شعبي في شارع الدفاع
المساحة: 12 لبنة، الارض حر
الواجهة 20 متر على الشارع نفسه مع مدخل الى السايلة امام مجمع العرضي بباب اليمن
شارع 18 متر
بيت لورثه ويشتوا يبيعوا
البصائر والاوراق موجودة
ومضمون ومافي اي مشاكل عليه
سعر اللبنة 25 مليون قابل للتفاوض
للتواصل : 770606013
in amperes A
Resistance R = V / I = P / I2 = V2 / P in ohms Ω
Power P = V × I = R × I2 = V2 / R in watts W

Electrical Potential - Ohm's Law
Ohm's law can be expressed as:
V = R I (1a)
V = P / I (1b)
V = (P R)1/2 (1c)
Electric Current - Ohm's Law
I = V / R (2a)
I = P / V (2b)
I = (P / R)1/2 (2c)
Electric Resistance - Ohm's Law
R = V / I (3a)
R = V2/ P (3b)
R = P / I2 (3c)
Electric Power
P = V I (4a)
P = R I2 (4b)
P = V2/ R (4c)
where
P = power (watts, W), V = voltage (volts, V)
I = current (amperes, A), R = resistance (ohms, Ω)
Electric Energy :Electric energy is power multiplied time, or
W = P t (5)
where
W = energy (Ws, J), t = time (s)
Electrical Motors : Electrical Motor Efficiency
μ = 746 Php / Pinput_w (6)
where
μ = efficiency
Php = output horsepower (hp)
Pinput_w = input electrical power (watts)
or alternatively
μ = 746 Php / (1.732 V I PF) (6b)
Electrical Motor - Power
P3-phase = (V I PF 1.732) / 1,000 (7)
where
P3-phase = electrical power 3-phase motor (kW)
PF = power factor electrical motor
Electrical Motor - Amps
I3-phase = (746 Php) / (1.732 V μ PF) (7)
where
I3-phase = electrical current 3-phase motor (amps)
PF = power factor electrical motor
Electrical measurements
Quantity
Name
Definition
frequency f
hertz (Hz)
1/s
force F
newton (N)
kg•m/s²
pressure p
pascal (Pa) = N/m²
kg/m•s²
energy E
work joule (J) = N•m
kg•m²/s²
power P
watt (W) = J/s
kg•m²/s³
electric charge Q
coulomb (C) = A•s
A•s
voltage V
volt (V)= W/A
kg•m²/A•s³
current I
ampere (A) = Q/s
A
capacitance C
farad (F) = C/V = A•s/V = s/Ω
A²•s4/kg•m²
@mc4eng_2 #المبدعون_للهندسة
Resistance R = V / I = P / I2 = V2 / P in ohms Ω
Power P = V × I = R × I2 = V2 / R in watts W

Electrical Potential - Ohm's Law
Ohm's law can be expressed as:
V = R I (1a)
V = P / I (1b)
V = (P R)1/2 (1c)
Electric Current - Ohm's Law
I = V / R (2a)
I = P / V (2b)
I = (P / R)1/2 (2c)
Electric Resistance - Ohm's Law
R = V / I (3a)
R = V2/ P (3b)
R = P / I2 (3c)
Electric Power
P = V I (4a)
P = R I2 (4b)
P = V2/ R (4c)
where
P = power (watts, W), V = voltage (volts, V)
I = current (amperes, A), R = resistance (ohms, Ω)
Electric Energy :Electric energy is power multiplied time, or
W = P t (5)
where
W = energy (Ws, J), t = time (s)
Electrical Motors : Electrical Motor Efficiency
μ = 746 Php / Pinput_w (6)
where
μ = efficiency
Php = output horsepower (hp)
Pinput_w = input electrical power (watts)
or alternatively
μ = 746 Php / (1.732 V I PF) (6b)
Electrical Motor - Power
P3-phase = (V I PF 1.732) / 1,000 (7)
where
P3-phase = electrical power 3-phase motor (kW)
PF = power factor electrical motor
Electrical Motor - Amps
I3-phase = (746 Php) / (1.732 V μ PF) (7)
where
I3-phase = electrical current 3-phase motor (amps)
PF = power factor electrical motor
Electrical measurements
Quantity
Name
Definition
frequency f
hertz (Hz)
1/s
force F
newton (N)
kg•m/s²
pressure p
pascal (Pa) = N/m²
kg/m•s²
energy E
work joule (J) = N•m
kg•m²/s²
power P
watt (W) = J/s
kg•m²/s³
electric charge Q
coulomb (C) = A•s
A•s
voltage V
volt (V)= W/A
kg•m²/A•s³
current I
ampere (A) = Q/s
A
capacitance C
farad (F) = C/V = A•s/V = s/Ω
A²•s4/kg•m²
@mc4eng_2 #المبدعون_للهندسة
Power Factor Correction Equipment: advantages and disadvantages
Normally, the power factor of the whole load on a large generating station is in the region of 0•8 to 0•9. However, sometimes it is lower and in such cases it is generally desirable to take special steps to improve the power factor. This can be achieved by the following equipment:
Static capacitor
The power factor can be improved by connecting capacitors in parallel with the equipment operating at lagging power factor. The capacitor (generally known as static capacitor) draws a leading current and partly or completely neutralizes the lagging reactive component of load current. This raises the power factor of the load. For three-phase loads, the capacitors can be connected in delta or star.
Advantages
They have low losses
They require little maintenance as there are no rotating parts
They can be easily installed as they are light and require no foundation
They can work under ordinary atmospheric conditions
Disadvantages
They have short service life ranging from 8 to 10 years
They are easily damaged if the voltage exceeds the rated value
Once the capacitors are damaged, their repair is uneconomical
Synchronous condenser
A synchronous motor takes a leading current when over-excited and, therefore, behaves as a capacitor. An over-excited synchronous motor running on no load is known as synchronous condenser. When such a machine is connected in parallel with the supply, it takes a leading current which partly neutralizes the lagging reactive component of the load. Thus the power factor is improved.
Advantages
By varying the field excitation, the magnitude of current drawn by the motor can be changed
by any amount. This helps in achieving step less †control of power factor
The motor windings have high thermal stability to short circuit currents
The faults can be removed easily
Disadvantages
There are considerable losses in the motor
The maintenance cost is high
It produces noise
Except in sizes above 500 kVA, the cost is greater than that of static capacitors of the same
rating
As a synchronous motor has no self-starting torque, therefore, an auxiliary equipment has to
be provided for this purpose
Phase advancers
Phase advancers are used to improve the power factor of induction motors. The low power factor of an induction motor is due to the fact that its stator winding draws exciting current which lags be-hind the supply voltage by 90 degrees. If the exciting ampere turns can be provided from some other a.c. source, then the stator winding will be relieved of exciting current and the power factor of the motor can be improved. This job is accomplished by the phase advancer which is simply an a.c. exciter. The phase advancer is mounted on the same shaft as the main motor and is connected in the rotor circuit of the motor. It provides exciting ampere turns to the rotor circuit at slip frequency. By providing more ampere turns than required, the induction motor can be made to operate on leading power factor like an over-excited synchronous motor.
Advantages
As the exciting ampere turns are sup-plied at slip frequency, therefore, lagging kVAR drawn by the motor are considerably reduced
The phase advancer can be conveniently used where the use of synchronous motors is inadmissible
However, the major disadvantage of phase advancers is that they are not economical for motors below 200 H.P
@mc4eng_2 #المبدعون_للهندسة
Normally, the power factor of the whole load on a large generating station is in the region of 0•8 to 0•9. However, sometimes it is lower and in such cases it is generally desirable to take special steps to improve the power factor. This can be achieved by the following equipment:
Static capacitor
The power factor can be improved by connecting capacitors in parallel with the equipment operating at lagging power factor. The capacitor (generally known as static capacitor) draws a leading current and partly or completely neutralizes the lagging reactive component of load current. This raises the power factor of the load. For three-phase loads, the capacitors can be connected in delta or star.
Advantages
They have low losses
They require little maintenance as there are no rotating parts
They can be easily installed as they are light and require no foundation
They can work under ordinary atmospheric conditions
Disadvantages
They have short service life ranging from 8 to 10 years
They are easily damaged if the voltage exceeds the rated value
Once the capacitors are damaged, their repair is uneconomical
Synchronous condenser
A synchronous motor takes a leading current when over-excited and, therefore, behaves as a capacitor. An over-excited synchronous motor running on no load is known as synchronous condenser. When such a machine is connected in parallel with the supply, it takes a leading current which partly neutralizes the lagging reactive component of the load. Thus the power factor is improved.
Advantages
By varying the field excitation, the magnitude of current drawn by the motor can be changed
by any amount. This helps in achieving step less †control of power factor
The motor windings have high thermal stability to short circuit currents
The faults can be removed easily
Disadvantages
There are considerable losses in the motor
The maintenance cost is high
It produces noise
Except in sizes above 500 kVA, the cost is greater than that of static capacitors of the same
rating
As a synchronous motor has no self-starting torque, therefore, an auxiliary equipment has to
be provided for this purpose
Phase advancers
Phase advancers are used to improve the power factor of induction motors. The low power factor of an induction motor is due to the fact that its stator winding draws exciting current which lags be-hind the supply voltage by 90 degrees. If the exciting ampere turns can be provided from some other a.c. source, then the stator winding will be relieved of exciting current and the power factor of the motor can be improved. This job is accomplished by the phase advancer which is simply an a.c. exciter. The phase advancer is mounted on the same shaft as the main motor and is connected in the rotor circuit of the motor. It provides exciting ampere turns to the rotor circuit at slip frequency. By providing more ampere turns than required, the induction motor can be made to operate on leading power factor like an over-excited synchronous motor.
Advantages
As the exciting ampere turns are sup-plied at slip frequency, therefore, lagging kVAR drawn by the motor are considerably reduced
The phase advancer can be conveniently used where the use of synchronous motors is inadmissible
However, the major disadvantage of phase advancers is that they are not economical for motors below 200 H.P
@mc4eng_2 #المبدعون_للهندسة