How much of the total slots are used for the reduction of the mmf wave harmonics?

In electrical machines, such as motors and generators, the reduction of the magnetomotive force (MMF) wave harmonics is an important concern for efficiency and performance. Harmonics in the MMF wave can lead to increased losses, noise, and vibration. The use of distributed windings and skewing techniques are common methods to mitigate these effects.

The concept of “slots” comes into play when discussing the armature winding of electrical machines. Slots are the openings in the stator or rotor where the coils of the winding are placed. The total number of slots directly impacts the MMF wave and its harmonics.

Regarding the question of how much of the total slots are used for the reduction of the MMF wave harmonics, it’s not accurate to say that a specific percentage of slots are dedicated solely to this purpose. Instead, the entire slot arrangement and winding distribution are designed to reduce harmonics. The design involves selecting the number of slots, slot distribution, winding pitch, and sometimes employing fractional slot windings to spread the windings more evenly. These design choices contribute to a smoother MMF wave by reducing certain harmonics.

Fractional slot windings, where the number of slots per pole per phase is not an integer, can be particularly effective in reducing harmonics by spreading the coils more evenly around the circumference and avoiding the concentration of coils that can exacerbate harmonic generation.

While the entire design contributes to harmonic reduction, there isn’t a separate allocation or percentage of slots specifically for this