Magnetic Circuit
Understanding the fundamentals of magnetic circuits in electrical systems.
🔹 What is a Magnetic Circuit?
- A magnetic circuit is a closed path followed by magnetic flux.
- It is similar to an electrical circuit, but instead of current, magnetic flux flows.
- Usually made of magnetic materials like iron to provide a low-reluctance path.
🔹 Important Terms
- Magnetomotive Force (MMF): It is the force that drives magnetic flux, similar to voltage.
- Magnetic Flux (Φ): The total magnetic field flowing through a circuit.
- Reluctance (ℜ): The opposition to magnetic flux, similar to resistance.
MMF (F) = N × I
Reluctance (ℜ) = l / (μ × A)
Magnetic Flux (Φ) = MMF / Reluctance
🔹 Comparison with Electrical Circuit
| Electrical Circuit |
Magnetic Circuit |
| Current (I) |
Magnetic Flux (Φ) |
| EMF (V) |
MMF (N × I) |
| Resistance (R) |
Reluctance (ℜ) |
| Ohm’s Law: V = I × R |
Φ = MMF / ℜ |
🔹 Example
- A coil with 500 turns carries 2A current.
- MMF = 500 × 2 = 1000 Ampere-Turns (AT)
- If the core has a reluctance of 250 AT/Wb, then:
Φ = MMF / ℜ = 1000 / 250 = 4 Wb (Webers)
🔹 Applications of Magnetic Circuits
- Transformers
- Inductors
- Relays
- Electric motors and generators