What are harmonics in single-phase motors?

Harmonics in single-phase motors refer to voltage or current waveforms that deviate from the ideal sine wave. In an ideal scenario, the electrical supply should produce a pure sine wave, which is essential for the efficient operation of AC motors. However, in real-world applications, various factors such as non-linear loads or switching devices can introduce harmonics into the electrical system.

These harmonics are integral multiples of the fundamental frequency and can lead to distortion in the waveform. The presence of harmonics can cause several issues, including reduced efficiency, overheating, and increased losses in the motor and related electrical equipment. This is why understanding and addressing harmonics is critical for maintaining the performance and longevity of single-phase motors.

The other choices do not accurately describe harmonics: efficient motor operation components are related to the design and control methods rather than waveform characteristics; additional voltage sources for starting pertain to specific motor types, like capacitor start motors; and frequency variations concern changes in supply frequency, which is a separate issue from waveform distortion.