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Universal motor reversal question

  1. Mar 2, 2016 #1
    Hello all, i have been tinkering with some series universal motors out of a vacuum cleaner and circular saws and would like some insight into the mechanism that determines directionality of the motor. Unlike dc motors i have used in the past, changing the wiring to the armature in relation to the field windings does not cause the motor to run in reverse. Instead, these motors still run in the same direction, which implies the cause of directionality is independent of the wiring configuration. So my question is this: are the windings on the armature on these motors designed so that they will only go in one direction? If not, then what does cause this unidirectionality?

    Thank you
     
  2. jcsd
  3. Mar 3, 2016 #2
    In a universal motor, the armature and field are wired in series. To reverse the direction, the polarity of the field connection must be reversed with respect to that of the armature.

    Some that are designed to be reversible will have two sets of field windings to allow the direction to be determined, dependent upon which field winding is employed.
     
  4. Mar 3, 2016 #3

    jim hardy

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    2016 Award

    Stefan is right.

    Are you suggesting these are not "universal motors" ?

    Just reversng the incoming power leads won't do it.
    Can you post a picture of where you reversed the wiring?

    http://top10electrical.blogspot.com/2015/01/reversing-direction-of-rotation-of.html

    6.1.png


    leave incoming alone and just swap the two blue wires...

    79499.jpg
     
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