Winding of inductor coils, Physics

Formers used for winding coils are ceramic or glass, because they are stable. Copper wire with silver plating is used up to 50 M Hz. Lit wire produces lower RF resistance than solid copper but it is effective below 2MHz. Above this frequency , RF currents flow through outside conductors of stranded wire. At these frequencies, universal winding is used to reduce self capacitance. In this winding, the wire is oscillated from side to side as the coil is wound.

HONEY COMB COILS: These windings are relatively widely spaced and turns per layer give honey comb appearance.

PROGRESSIVE UNIVERSAL WINDINGS:

It is similar to universal winding except this instead of spilling back and forth in same area, the spiralling also progresses along the former. With this type of winding, it is possible TO HAVE HIGH PERMEABILITY in tuned inductors.

QUALITY FACTORS OF COILS

It is figure of merit of coil.

Q = XL/R = tanφ

 Q is dependent upon frequency. If Q is high, then the sensitivity of circuit is good.

Choice of size of wire: For audio frequencies, standard wire gives good response. At higher frequencies, it is desirable to use many standards to have high Q. Cost increases with more standards.

CHOICE OF WIRE INSULATION: The insulators control the spacing between wires and winding size. It is necessary to select insulators with low dielectric losses. Enamel coated multi stand wires insulated with flannel of silk, cotton, glass, etc.

Choice of formers: The size of former is decided by space limitation, winding size, etc. The material used for the former should be strong, dimensionally stable with temperature changes and electrically good but fragile and costly. Peonies are less costly but vary widely in their electrical properties. In transmitter coils, ceramic formers are used.

Choice of finish: Wax varnishes or lacquers are used for final finish to make them mechanically and electrically stable.

Choice of shielding: To prevent undesirable coupling between inductors, it is necessary to use a shield on it. Shield is a conducting material, copper or aluminium. Aluminium is less costly. As the shield is not a perfect conductor, losses add to the losses in inductor.

Coupling of coils: To obtain close coupling, second winding is wound is continuation with first winding, separated by a layer of tape. For loose coupling, winding are placed apart on the same former or placed side by side with ferrite rods.

Posted Date: 7/9/2012 6:59:12 AM | Location : United States







Related Discussions:- Winding of inductor coils, Assignment Help, Ask Question on Winding of inductor coils, Get Answer, Expert's Help, Winding of inductor coils Discussions

Write discussion on Winding of inductor coils
Your posts are moderated
Related Questions
Radiation Hazards: 1. They can injure our body cells. 2. Excessive radiation might be cause cancer. 3. Energetic radiation penetrates inside the body and can cause other

how much energy is required to raise an object of 300g that is initially at rest to a height of 2m and simultaneuosly give the object a velocity if 4m/s?


Can you give me few applications of coupled oscillator concepts?

A thin uniform rectangular sign hangs vertically above the door of a shop. The sign is hinged to a stationary horizontal rod along its top edge. The mass of the sign is 2.40 kg and

How is laser in treatment use as cooling? Lasers cooling treatment: A technique which has had recent success is laser cooling. It involves atom trapping, a process where a n

There is a clever kitchen gadget for drying lettuce leaves after you wash them. It consists of a cylindrical container mounted so that it can be rotated about its axis by turning a

In two-dimension motion a body go in a plane. e.g. a particle rolling in a circle, a cricket ball caught by a fielder. In the first case the body can go round with a fix velocity o

Conservation of Energy Conservation of energy is not all about turning off the computer when you are not using it. Energy is not created or destroyed, it just changes forms. En