What mean by higher resistance of stepper motor shaft while rotating it with hand?

Discussion in 'General Electronics Chat' started by crazybuoy, Nov 23, 2015.

  1. crazybuoy

    Thread Starter Active Member

    Sep 19, 2010
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    I found many small and big stepper motors in market.The shaft of some motors need a low power to rotate by hand, means it has low resistance and it moves easily by hand.

    And some I found that their shaft need some more hand power to rotate its shaft, means it has more resistance.

    Is the level of resistance also affects the torque power?
    Has the motor with higher resistance more torque?
     
  2. alfacliff

    Well-Known Member

    Dec 13, 2013
    2,449
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    stepper motors generate a low voltage when turned. that messes up the resistance reading.
     
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  3. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    Greater (input) torque implies greater PM field strength and, hence, greater 'back' EMF with increased interference to the resistance indication --- Please be advised that repurposed 'steppers' are a poor expedient for generators/instrumentation transducers...

    Best regards
    HP
     
    Last edited: Nov 23, 2015
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  4. RichardO

    Well-Known Member

    May 4, 2013
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    Make sure that none of the motor wires are shorted to each other when doing the test. If the windings are shorted a lot more torque will be needed to tun the shaft because the motor is acting as a generator into a heavy electrical load.
     
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  5. MaxHeadRoom

    Expert

    Jul 18, 2013
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    This is called the Residual torque is a result of the p.m flux acting on the stator poles.
    As opposed to Holding torque which is the amount of torque required on the motor shaft at zero rpm that is required to move the shaft away from its holding position when powered at the rated current.
    Max.
     
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  6. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
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    I believe the reference here is to mechanical resistance, not electrical.
     
  7. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    @crazybuoy -- If this is the case please see posts #4 and #5:)
     
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