"During my school days, I have a question in my mind. An electromagnetic coil (inductor) which is nothing just a roll of insulated wire upon which multiple turns been wrapped. That roll of wire become electromagnet when a power supply get connected to it.
But if that same wire roll unwinded & stretched into a straight conductor & than a supply get connected to it, A short circuit will be the result.
The question is - What was that thing which is opposing the current flow in wire wrapped coil which is not present in straight conductor."
INDUCTOR
Inductor is a from of coil in which number of turns of insulated wires been wrapped. It stores energy in the form of electromagnetic field. Ferromagnetic material may or may not be sandwiched as a core inside the coil. It is two terminals passive element which is available in different shapes & sizes.
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| Air core inductor |
Any conductor which is having a current flow through it, Magnetic field get generated around that conductor. Since in inductor, Wires are been wrapped into the circular motion that's why more magnetic field from all around links to each other. Due to extra magnetic field linking in circular coil if compare with Straight conductor's magnetic field; Extra emf get generated in the inductor.
The generated emf in such a direction that it always oppose the change which has generated it. It oppose the current when current increasing in the circuit & It helps to maintain the current when current decreasing in the circuit.
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| Toroidal shape Inductor |
Now The Answer of my question is
In conductor to oppose the electric current there is only resistance While in inductor along with resistance there is Back EMF & that generated emf is always in a direction to oppose the change which has generated it.
INDUCTANCE
The inductor is characterized with the term inductance (L). It is the tendency of conductor to oppose the change of electrical current flowing through it. Inductance is directly proportional to the flux linkage (Φ) such that L=Φ/I(I=current). The more the flux linkage, the more will be the inductance(L).
The units of inductance is Henry.
Since the inductance of the inductor depends upon flux linkage which means it ultimately depends upon the geometrical shape of current flow & surrounding material of inductor. That's why inductors are designed in circular form & core is being sandwiched with ferromagnetic material in between the coil to increase the inductance up to multiple times.
APPLICATIONS OF INDUCTOR
Electromagnets
Electromagnetism play a very important role in Electrical System. An Electromagnet is a type of inductor Which behave like a magnet when power supply get connected across it. AC as well DC operated, Electromagnets are there.
In Contactors, Relays, Circuit Breakers, Electric bells & many more electrical products are there in which electromagnet is the key component. In these type of products in along with electromagnet, Spring mechanism is being used in Such a way that when coil get magnetized it pulled the system & when coil get demagnetized, System get pushed away automatically.
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| Parts inside the Contactor in Which electromagnet the main component |
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| 8 Pins 16Amps Relay having a coil voltage 24VDC. |
Transformers
Transformers are the powerful Electrical machines which are used widely all around the world. Transformers transform power from one circuit to another statically without any type of movement with higher efficiency. Transformers are type of inductors in which inductors are coupled to each other through common magnetic core. Generally, It has two windings primary & secondary. Primary gets power supply as an input while power at secondary side get transferred magnetically.
Power & frequency at both Input-output remains the same in transformers, It is the voltage & current which changes accordingly. By changing the number of turns in Primary & secondary windings, voltage level can be adjusted.
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| Low rating small Transformers |
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| Transformer 500KVA having a voltage ratio 11000/400 |
Line Reactors
Non linear loads like variable frequency drives, Rectifiers & SMPS produces harmonics in the circuit Which increases the losses in the system. For the preventions of harmonics & transients in the circuit, Line Reactors are being connected in the circuit just before the non linear loads.
(Harmonics are the unwanted signals with higher frequency size which are the multiple times of fundamental frequency.)
The property of inductor to oppose the change in line current which is flowing through it; is used in Line reactors which blocks the harmonics generation in the circuit.
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| 3 Phase line Reactors/Choke connected Infront of 2.2kW VFD A 3 phase Line Reactor/Chowk connected before 2.2KW- 3phase Variable frequency drive. |
Electrical Motors
Electrical motors are the powerful electrical machines which transforms electrical power into mechanical power. These are working on the principle of faraday law of electromagnetic induction. Winding inside the motors are the type of inductive coils Which transform electrical power into electromagnetism.
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| 5.5 KW-960rpm 3phase415Volts Induction motor |
Filter Circuits
Inductors opposes the AC signals while it accepts the DC signals on another side capacitors are opposites of inductors which accepts AC & rejects DC. With Appropriate calculation according to the requirement, Inductors or capacitor or combination of both can be connected in way to obtain the filter circuit.
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