Unipolar stepper motor additional part. What is this?

Discussion in 'The Projects Forum' started by crazybuoy, Jul 31, 2016.

  1. crazybuoy

    Thread Starter Active Member

    Sep 19, 2010
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    I have a Unipolar stepper motor with attached an additional coil as show in following two images. It takes high mechanical force, while moving motor's shaft with hand. And after removing this additional part by removing four screws, then it takes just a little mechanical force to move the shaft with hand.

    Please guide me what is this attached additionally, how to use it and what is its benefit?
     
  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Very likely an electromechanical clutch or brake. If you add voltage to the extra coil, is the shaft easier to turn?

    The advantage is to provide a brake for the motor.

    John
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
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    +1 on a brake, but one section should be attached to the shaft and rotate normally while the other remains stationary, does the rear disc revolve with the shaft?
    Max.
     
  4. AlbertHall

    Well-Known Member

    Jun 4, 2014
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    If the motor has a shaft at the other end (can't see in the pictures) then the moving part of the brake could be completely enclosed in that casing.
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Anything is possible.;)
    Max.
     
  6. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    I have several steppers that were attached to precision valves that also had optical encoders on them too.
     
  7. crazybuoy

    Thread Starter Active Member

    Sep 19, 2010
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    I also think so, but not sure, I did not attach this motor to driver yet. If I do, then five motor wires will go to driver, then how should I use two wires of so-called clutch or brake. I also checked it by opening it, there was not any gear inside.

    At rear, it has two disks like (disk+separator+disk), and last rear disk revolves with shaft. How should I apply voltage to this additional part while attaching this motor to driver?

    I am sending further two images, motor has shaft both sides, plz check images.

    Please send the clear images of those motor having optical encoder.
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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    A typical brake voltage would be 24vdc, what is the resistance across the two leads?
    It does not appear to be an encoder.
    If it is a brake, it should be energized as soon as a command is given to the motor.
    Max..
     
  9. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    For what voltage is your motor rated? If it is low-voltage, I might try 12 V on the brake first, perhaps with an in-line resistor or DC light bulb too just to be conservative.

    John
     
  10. crazybuoy

    Thread Starter Active Member

    Sep 19, 2010
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    The sticker on Break says "24v,7w". Any how, I don't want to use break, I just bought this motor with this additional component. I have separated it from motor.
     
    Last edited: Aug 1, 2016
  11. MaxHeadRoom

    Expert

    Jul 18, 2013
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    It is Brake BTW, you certainly do not want to 'Break' it! :)
    Removing it will lighten the load and improve the torque slightly when in motion.
    Max.
     
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