Control Differences Between Ac Induction Motor And Brushless Dc Motor?
Answer : From All About Circuits: Brushless DC motors are similar to AC synchronous motors. The major difference is that synchronous motors develop a sinusoidal back EMF, as compared to a rectangular, or trapezoidal, back EMF for brushless DC motors. Both have stator created rotating magnetic fields producing torque in a magnetic rotor. Construction wise, there is essentially* no difference. The motor in the above diagram could be called an "AC Induction Motor" or a "Brushless DC Motor" and it would be the same motor. The main difference is in the drive. An AC motor is controlled by a drive consisting of a sinusoidal alternating current waveform. It's speed is synchronous with the frequency of that waveform. And since it is driven by a sine wave, it's Back-EMF is a sine wave. A single phase AC Motor could be driven from the wall socket and it would turn at 3000 RPM or 3600 RPM (depending on your country of origin having 50/60Hz mains). Notice that I said...