Which is More Efficient?

Discussion in 'General Electronics Chat' started by cjdelphi, Jul 27, 2010.

  1. cjdelphi

    Thread Starter New Member

    Mar 26, 2009
    I got wondering Brushless Motor vs conventional motor.

    If I spin a regular motor consisting of a brush perm magnets I'll get a voltage out (obviously), but this is not the case for a Brushless motor...... But... here's what i was thinking, what If you could use a small battery to energize the magnetic field then spin the motor and use the energy from that to keep the second field powered?...

    Would that be more or less efficient of producing energy than a conventional motor?
  2. tom66

    Senior Member

    May 9, 2009
    Since the conventional motor produces no voltage, it is probably more efficient, since most of the energy is going to the motor. But I don't use motors much so I can't be sure.
  3. sage.radachowsky


    May 11, 2010
    Brushless is more efficient.

    A traditional motor with a brush uses the brush to create the timing of the magnetic fields on the rotor, as the brush moves from one contact to the next.

    A brushless motor uses electronics to create the timing of the changing magnetic fields, on the stator. The rotor typically has permanent magnets.

    When you spin a brushless motor, there is no voltage because the control electronics are off. It's not a simple (and bidirectional) system like a brush motor.

    On the other hand, it is possible to generate power with a brushless motor if it's designed for that purpose. In that case, it would be called a brushless dynamo.

    Because the timing is controlled by electronics rather than a physical mechanism, the brushless motor is more complicated to design, but it also allows much more nuanced control, resulting in precise speed and torque control, and greater efficiencies at many different torques and speeds.