The additional losses owing to the higher order mmf harmonics occur mainly in windings of squirrel cage rotor.

The additional losses caused by higher order magneto-motive force (MMF) harmonics primarily affect the windings of the squirrel cage rotor due to several factors. These losses are not as pronounced in the windings as they are in the rotor bars and surrounding metal parts of the rotor assembly. Here’s why:

1. Skin Effect in Rotor Bars: Higher order harmonics have a higher frequency, which leads to a more pronounced skin effect in the conductive materials of the rotor. The skin effect causes the current to concentrate near the surface of the conductor, reducing the effective cross-sectional area through which the current can flow. This leads to an increase in resistance and, consequently, higher I²R losses (where I is the current and R is the resistance). Since the squirrel cage rotor bars are made of conductive materials, such as aluminum or copper, they are particularly susceptible to these losses.

2. Eddy Currents: Higher order harmonics also induce eddy currents in the rotor and other conductive components of the motor. Eddy currents are loops of electrical current induced within conductors by a changing magnetic field in the conductor, according to Faraday’s law of electromagnetic induction. These currents flow in paths that create their own magnetic fields, which oppose the original field. The resistance of the material to the flow of these eddy currents results in heating, which is a form of energy loss.

3. Saturation and Flux Weakening: The harmonics can cause