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DC brushless motor vs. AC motor

  1. Aug 10, 2014 #1
    I noticed that common technology such as brushless DC motors use AC to drive them. What exactly makes DC brushless motors different from AC motors if they both ultimately take in AC? Why even refer to DC brushless motors as DC motors if they're not even driven by DC? I understand the source is a DC source but it still goes through an inverter and so it's being fed AC.
  2. jcsd
  3. Aug 11, 2014 #2


    Staff: Mentor

    DC brushless motors are stepping motors and may have an alternating current waveform that isn't necessarily sinusoidal like standard AC is. There are other advantages as well that make DC brushless a better choice for projects.

  4. Aug 11, 2014 #3


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    Science Advisor
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    2017 Award

    Is it possible that you are getting overexcited about the precise use of terms here? The switching circuitry in a 'brushless' motor is little more (in essence) than the copper / carbon commutator in a normal DC motor. Both mechanisms are needed to produce the alternating current through half of the motor in order to perpetuate the rotational motion. They are both supplied with DC and and "DC" refers to that and not to what goes on inside the box.

    If you feed a brushless motor with AC, it is quite simple (relatively, anyway) to produce the appropriate volts on the windings to produce the rotation.
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