Parallel Magnetic Circuit - Experts Electrical

Definition of Parallel Magnetic Circuit

A parallel magnetic circuit is defined as a magnetic pathway with two or more branches for magnetic flux, analogous to a parallel electric circuit. Such circuits feature multiple flux paths with varying cross-sectional areas and materials, each potentially composed of different magnetic components.

Parallel Magnetic Circuit Analysis

The figure above depicts a parallel magnetic circuit, where a current-carrying coil is wound around the central limb AB. This coil generates a magnetic flux φ₁ in the central limb, which travels upward and splits into two parallel paths: ADCB and AFEB. The path ADCB conducts flux φ₂, while AFEB carries flux φ₃. As evident from the circuit:

Parallel Magnetic Circuit Characteristics

The two magnetic paths ADCB and AFEB form a parallel magnetic circuit, where the ampere-turns (ATs) required for the entire parallel circuit equal the ampere-turns needed for any single branch.

As is known, reluctance is defined as：

Parallel Magnetic Circuit MMF Calculation

Thus, the total magnetomotive force (MMF) or ampere-turns required for a parallel magnetic circuit equals the MMF of any single parallel path, as all branches experience the same applied MMF.

Incorrect Notation Clarification:

The total MMF is not the sum of individual paths (a common misconception). Instead, since parallel magnetic paths share the same applied MMF, the correct relation is:

Total MMF = MMF for path BA = MMF for path ADCB = MMF for path AFEB

Where φ₁. Φ₂, φ₃ is the flux and S_1, S₂, S₃ are the reluctances of the parallel path BA, ADCB and AFEB respectively.