The article provides an overview of magnetic flux density, explaining its definition, unit of measurement, and formula for calculation. It also includes example problems demonstrating how to determine flux density in different scenarios.
Magnetic Flux density is the measure of the number of magnetic lines of force per unit of cross-sectional area.
The general symbol for magnetic flux density is B and the unit is the weber per square meter (Wb/m2). One weber per square meter is called a tesla (T).
If both the total flux and the area of the magnetic path are known, the flux density is found from:
Where:
- B = flux density in tesla (Wb/m2)
- Φ = total flux in webers
- A = area in m2
Magnetic Flux Density Example
A magnetic circuit has a cross-sectional area of 100mm2 and a flux density of 0.01T. Calculate the total flux in the circuit.
$$\Phi =BA=0.01\times 100E-6=1E-6Wb$$
Note: The answer is expressed in webers and not in lines of force.
Example of Magnetic Flux Density 2
An air core coil has 0.65 μ Wb of flux in its core. Calculate the flux density if the core diameter is 4 cm.
Solution
First, we’ll calculate the core area:
\[A=\pi ~{{r}^{2}}=3.14*{{\left( 0.02m \right)}^{2}}=1.256*~{{10}^{-3}}~{{m}^{2}}\]
Now, we can calculate the magnetic flux density using the following formula:
\[B=\frac{\varphi }{A}=~\frac{0.65*~{{10}^{-6}}~Wb}{1.256*~{{10}^{-3}}~{{m}^{2}}}=5.175*~{{10}^{-4}}~T\]
Magnetic Flux Density Key Takeaways
Understanding magnetic flux density is crucial in various applications, including electrical engineering, electromagnetism, and industrial machinery. It plays a key role in the design of transformers, electric motors, and generators, where efficient magnetic field control is essential for performance and energy efficiency. Additionally, magnetic flux density is fundamental in medical imaging technologies like MRI and in wireless power transfer systems. By mastering the principles of flux density calculation, engineers and researchers can optimize the functionality and reliability of electromagnetic systems across multiple industries.
