What Do You Know about Current Coils?
A current coil is basically a coil, such as, a wire wrapped around an electrical conductor. Usually, the coil is made out of insulated copper wire and the conductor is a soft iron core. When the coil wrapped around the conductor carries current, it has been observed that the coil starts behaving like a magnet. This property of a conductor, when wrapped around a current-carrying coil, is called electromagnetism. A popular physics experiment is done using the same phenomenon. When nails are put across a table with a conductor coiled around a current-carrying wire, then the nails of the table stick to the coil. The reason why these nails glue to the wire is electromagnetism.
A current coil is an electrical conductor similar to a wire coil. Consider a coil of insulated copper wire wrapped around a soft iron core. We put an iron nail on the table, put the coil on the nail, and see what happens. Now we can connect the 9 V battery to the coil terminals and see what happens now. The coil works like magic. The magnet attracts iron nails, so repeat this experiment with more turns and a stronger battery. Notice how the intensity changes. The coil-shaped conductor acts like a magnet, and the property of this conductor is called an electromagnet. The strength of the electromagnet depends on the number of turns in the coil. One wire doesn't create enough magnetic field around the conductor to attract the iron nail on the table, so it winds the conductor several times to create an inductive induction- magnetic field. Multiplying by the number of turns, the strength of the induced magnetic field also depends on the amount of current flowing through the conductor.
Important Factors for a Current Coil
There are a number of factors on which the strength of electromagnetism depends.
The first factor determining the strength of the current coil is the number of turns. The more the turns, the more the current in amperes. The magnetic field also gets multiplied with the number of turns in a coil.
The second important factor is the strength of the current flowing through the conductor. The greater the electric current, the more strength of the current coil.
The third factor is the material in which the conductor is made up. Generally ferrous or iron-bearing is used to improve electromagnetism around a current coil. Also, the use of alloys such as aluminum-nickel-cobalt can also produce strong magnetic fields.
The fourth and last factor that is important for the current coil is the temperature. It has been found that current-carrying ability is improved at lower temperatures. Moreover, the strongest magnets are made of superconductors cooled with liquefied nitrogen or helium.
Applications of Current Coil
Due to its unique ability to produce electromagnetism, there are many applications of the current coil in the real world.
A current coil is popularly known to be used as a Can Crusher. This application is based on the electromagnetic field that is generated when a can is placed inside a coil which then gets further energized to bend and deform the can by compressing it into a flat disc.
Current coils are also commonly used as electromagnets. There are specific types of electromagnets as well such as a solenoid, Maxwell coil, Voice coil, and Degaussing coil.
Another common application of the current coil is Magnetic Cranes. In landfills, the trash also contains a large number of metals which can either take years to degrade or can simply be recycled and reused. An electromagnet can be of a big help here. The giant electromagnet attracts and sticks all the metal components in the trash at dump yards and landfills. Moreover, these metal scraps can be easily removed by the electromagnet when it is de-energized. This function was not possible with permanent magnets, and people had to remove metal scraps manually earlier.
Wrap up on Current Coil
The concept of electricity and magnetism do overlap when studying physics. The example of a current coil explains the co-occurrence of the above two phenomena which is then called electromagnetism. The electromagnetic field created when current passes through the current coil can serve multiple purposes. Some of these real-life applications are electromagnets, can crushers and magnetic cranes.
Specifications of an Electric Coil
An electrical coil consists of a core and a wire wound around the core. Some types of electrical coils do not have a core and are simply wound with windings.
Wire Spool
The shape and dimensions of the wire used in the spool are selected for a specific function. Inductance, energy dissipation, dielectric strength, and magnetic field strength are key factors in determining wiring selection. The most efficient coils limit material and volume. There is a relationship called the duty cycle between the area of an electrical conductor and the space of a winding. Circular wire always has some gap, which increases due to the number of turns and the gap between the layers created by the insulator. The fill factor is always less than 1 and ranges from 0.01 to 0.05. Using rectangular, square, and flat wire is a way to increase the fill factor.
Coil Wire
In Sag Harbor Industries, there are three types of duty cycles depending on the ratio between the cross-sectional area of the part and the cross-sectional area of the coil. The duty cycle calculation ranges from 0.1 to 0.5, with symbolic high, medium, and low duty cycles. Tightening the wire reduces space and increases the filling rate. This in turn increases the efficiency of the electrical device and improves its conductivity. The best winding for round wire is to fill a groove 300° below the perimeter of the spool with the top layer of wire.
Gap Fill Factor
A winding is an insulated conductor used to exchange electrical and magnetic energy. In most cases, the wire is covered with a thin layer of copper or aluminium with thin laminate insulation, which is usually the first choice for most electrical coils when investigating factors such as the chemical, physical and mechanical properties of copper. High purity copper is used in high temperature or high-temperature systems or engines that use hydrogen for cooling.
Galvanized Wire
Galvanized Wire is used in environments where conditions can degrade or damage wiring. The sheath of the wire is gold, silver, or nickel of various thicknesses and is covered with insulation. Electroplating provides the best protection in harsh environments. Coating the wire greatly improves properties such as conductivity.
Insulation Type
Electrical coils use a variety of insulating materials depending on the application temperature range. Material types include polyvinyl chloride (PVC), polyurethane, polyester, and various forms of polyimide. When choosing an insulating material, polyimide is used, whose temperature reaches 250 °C. During the winding process, the wire is heated and the insulating material sticks to each other.
Insulation increases heat resistance and protects wires. The main function of wire insulation is to prevent them from touching the wire. This can cause a short circuit. Each type of Insulation has different properties including heat capacity, thickness, and application.
Polyester - Polyester has high-temperature properties and very low brittleness. high wear resistance. Excellent winding properties, flexibility, and resistance to heat and solvents. The polyamide coating on polyester improves the wrinkle and flow properties of the thermoplastic.
Polyimide - Polyimide is one of the most widely used insulation types for electromagnetic coils. It has excellent mechanical properties and can be operated at high temperatures. Polyimides are polymers composed of imide monomers with two acyl groups bonded to nitrogen. Because of the mechanical and thermal properties of polyimide, it can withstand temperatures over 240 °C and its use with electromagnetic coils has expanded.
Fun Facts
Difference Between Current Coil and Pressure Coil.
A pressure coil is also known as the voltage coil and is generally used in a wattmeter. There is a prominent difference between current coil and pressure coil The current coil is always connected in series. While the pressure coil is connected in parallel with the load. Moreover, the current coil measures the current while the pressure coil measures the voltage. Both the coils are used in a wattmeter scale and to measure current or voltage in tension transmission lines.
Conclusion
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FAQs on Current Coil
1. What is Electromagnetism?
The concept of electromagnetism can be defined as the use of coils of wire that carries current around a soft magnetic material producing a field of electricity and magnetism at the same time. When the electric current flows through the coil of wire around a conductor, electromagnetism is produced. The magnetic field around the conductor also has a direction with both “North” and “South” poles determined by the direction of the flow of current through the conductor. It has been further established that a circular electromagnetic field is created with magnetic lines of flux that form complete loops when the electric current is passed through a conductor. Look through Vendantu’s website to get more insight on the same.
2. What are Electromagnets?
Electromagnets can be defined as coils of wire with an electrical current passing through the coil and it behaving like bar magnets with distinct north and south poles. Moreover, the magnetic field that is produced around the current-carrying coil is static at both the poles and much stronger towards the center of the coil. As mentioned above, the strength of the electromagnet depends on the number of turns of wire in the coil, the amount of current flowing through the coil, the type of core material of the coil, and the temperature. The current flowing through the coil is expressed as Magneto Motive Force in the ‘I’ current flow through a coil of N turns. Look through Vendantu’s website to get more insight on the same.
3. Does Vedantu provide previous papers?
Yes, Vedantu provides previous year papers. The previous year papers are important for the students as they get an idea about the questions asked in the exams. With these question papers, students can practice many related questions from the syllabus. Using these papers, they should analyse the subject's strengths and weaknesses. Students will face exams with more confidence if they solve as many previous year questions as they can. This will familiarize them with the paper type and pattern. Also, it helps the students to manage their time during the exams. Students should definitely study and practice them thoroughly in order to ace the exams. You can access the papers through the website.
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