Thursday, January 21, 2010

Magnetic field flux, Strong Magnetic Field and Magnetic Flux Density



Flux Magnetic Field - Magnetic fields can not be invisible to the eye but the proof can be observed with a compass or a fine powder of iron. The area around which penetrated by lines of magnetic force is called magnetic force or magnetic field. The number of lines of force in a magnetic field called magnetic flux.

Figure 1. Air-core winding wire and lines of magnetic force.

According to the international unit of magnetic flux magnitude (Φ) measured in Weber, abbreviated Wb and is defined by:

"A homogeneous magnetic field has magnetic flux of 1 weber deducted if a Conductor on the lines of magnetic force they will be for one second will cause electromotive force (emf) equal to one volt"

Weber = volts x seconds

[Φ] = 1 Voltdetik = 1 Wb

Winding wire electrified DC then will arise in the core windings
magnetic field which flows from north pole to south pole, as shown in Figure 2.


Figure 2. Local Effect of magnetic field.
Effect of magnetic force will be covering the area around the winding given color shading. Magnetic force (θ) is proportional to the number of turns straight (N) and the amount of current flowing (I), briefly the magnetic field is proportional to the ampere-wrap.
θ = I. N
[Θ] = Ampere-turn
where;
θ = style magnetic motion I = Current flowing into the windings N = Number of turns of wire
Example: 500 winding wire wrap, 2 A. energized Calculate a) the magnetic force b) if the case of a) used 1000 wrap how much flow? Answer: a) θ = I. N = 500 wrap x 2 A = 1.000 Ampere-wrap b) I = θ / N = 1.000 Amper-lilit/1000 wrap = 1 Ampere.

Strong Magnetic Field toroidal shaped winding-Two different sizes in diameter. Large toroidal winding has a larger diameter, so that a larger circumference. Small toroidal winding thus has a smaller circumference. If both have the windings (N) the same, and channeled currents (I) are equal then the magnetic force (Θ = NI) were also similar. What will differ is the strong magnetic field (H) of the two windings above.
The magnetic field equation is:




Where:
Strong magnetic field H =
lm = length of track
θ = style magnetic motion
I = Current flowing into the windings
N = Number of turns of wire

Example: toroidal coil with 6,000 turns of wire, a magnetic path length 30cm, flowing currents of 200 mA. Calculate the magnetic field strength
Answer:
H = I.N / Im = 0.2 A. 6000 / 0.3 = 4000 A / m

Magnetic Flux Density - The effectiveness of magnetic fields in the use frequently determined by the extent of "magnetic flux density", meaning that the magnetic flux that is on the wider surface low density and intensity of the terrain is much weaker, while the narrower surface magnetic flux density and intensity will be strong higher terrain.

Magnetic flux density (B) or magnetic induction is defined as:

"cross-sectional area flux of unity"

Magnetic flux unit is Tesla. Magnetic flux equation is:




Where;
B = magnetic field density
Φ = magnetic Flux
A = core cross-section

Example: winding wire core forms a square 50mm x 30 mm, produces a magnetic flux density of 0.8 Tesla. Calculate the large magnetic flux.

Answer: B = Φ / A, then Φ = BA = 0.08 T x (0.05 mx 0.03 m) = 1.2 mWB

By ....

HaGe – http://dunia-listrik.blogspot.com