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Line current three phase motor in six step commutation

  1. Jun 18, 2015 #1

    I have got a three phase motor connected in delta that is controlled in six step commutation. When I measure the line current of one of the phase under oscilloscope, I got something like this :

    Can anyone tell me why the amplitude of the current isn't 3.1A and -3.1A? What I got here is 3.1A and -4.1A which is not symetrical.
  2. jcsd
  3. Jun 18, 2015 #2


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    Gold Member

    I'm worried about the spikes when the signal = -4A. Could be that it is trying to come up with -3.1A, but it cannot ( connection lost again ).

    Bad soldering in your drive?
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