mechanical brake

Discussion in 'The Projects Forum' started by pavelnedved, Apr 27, 2012.

  1. pavelnedved

    Thread Starter New Member

    Apr 17, 2012
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    Hi guys!

    Is it possible to have a mechanical brake (not electric brake) on a small stepper?

    I don't know much about mechanical braking to be honest. Ok I do have a bike, but I mean mounted on small motors :).
    Any of you have any experience with/knowledge of it?

    Cheers,
    Tim
     
  2. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    397
    'See no reason why a mechanical brake could not be used on small motor. More suggestions with more details.
     
  3. MrChips

    Moderator

    Oct 2, 2009
    12,440
    3,360
    No. The proper way to stop a stepper is to decelerate the stepper motor.
     
  4. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    If you are looking for holding torque while not running the motor, these might work for you. Several other manufacturers make similar units.
    http://www.dingsbrakes.com/
     
  5. John P

    AAC Fanatic!

    Oct 14, 2008
    1,634
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    Certainly you can put a brake on a stepper, like any other rotating device. But in general the motor will have holding torque as long as you keep it powered, and you shouldn't need a brake. Still, if you want to maintain a position with power off, maybe it's what you have to use.
     
  6. pavelnedved

    Thread Starter New Member

    Apr 17, 2012
    7
    0
    Yes, it's more something like a holding torque. The problem is that there is an external electromagnetic field and I don't really trust the consequences it might have on positioning or the holding torque!

    So the idea would be the following sequence:

    switch off external field - rotate the motor - stop the motor - brake it mechanically -switch the field back on - do something with the field - switch off external field - ....

    For this, I would use a double shaft stepper, the second shaft (which is pointing downwards) being used to brake the motor.

    So you have the (false) floor the motor is standing on with a hole in it for the second shaft to go through. Then the brake should be attached to the other side of the floor.
    The brake only has 1cm of shaft to work with. Do such small brakes exist? Anybody has any experience with it?

    Thanks for the website. I'll check it out!
     
  7. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
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    your brake will probably be inductive, so wouldn't you be concerned about field implications with it? You can get different actuations, but just saying...
    Holding torque is as much a consideration in spec'ing a motor, as is driving torque. Size it appropriate to your needs.
     
  8. John P

    AAC Fanatic!

    Oct 14, 2008
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    Ah, but you can get brakes which are "power on" or "power off". Choose the right one, and there wouldn't need to be any electricity flowing while the motor is stopped.
     
  9. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
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    this is true if one assumes that the brake is large enough to negate any effects of this 'external magnetic field'. Sufficient holding torque is going to be either in the motor or the brake. Cost wasn't indicated as a factor, nor was size. A brake may be the right choice??
     
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