Elastic deformation (compression) of trapezoidal wave
corrugated form does not changing the width of the contact zone, as connected only with the phenomenon of its side faces loss stability.
The trapezoidal wave
or square wave brushless DC motor (BLDC) is a kind of brushless DC motor which is recognized universally (Guo, 2008; Abreu, 2015).
According to the Fourier series and actual experience, trapezoidal wave
shapes have higher frequency harmonics that add to the EMI field.
With the sinusoidal motor current wave form developed, instead of trapezoidal wave
form which typical permanent magnet motors employ, Ecoheart achieves low torque ripple, low vibration and acoustic noise and much reduced harmonics.