Hi speed Stepper

Discussion in 'The Projects Forum' started by araforn, Oct 6, 2011.

  1. araforn

    Thread Starter New Member

    Jul 26, 2011
    18
    0
    Hi guys.
    As part of a college project I need to get control of a stepper motor. I first need to get it to run in excess of 1000 rpm and then get positional control to orientate it in the same direction each time.
    I have a good idea how I will do this but my biggest problem is choosing the right stepper motor. I can't seem to determine the max speed from the data given for each motor I look at.
    The driver I will be using will be this http://www.ebay.ie:80/itm/ws/eBayIS...250786984357&ssPageName=ADME:B:EOIBSA:IE:1123 and the load on the rotor will be extremely small (small nylon turntable mounted to the rotor).
    Can anyone tell me what is the best way to interpret stepper motor data sheets for maximum speeds?? For instance will this motor run at speeds higher than 1000 rpm?? http://www.ebay.co.uk:80/itm/ws/eBa...em=260785710533&ssPageName=ADME:X:RTQ:GB:1123
    Thanks in advance for any help guys :)
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    The rotational speed is given by #steps per rotation / steps per second. It is hard to find steppers that can go over 5000 steps per second. 200 steps/rotation likewise. That NEMA stepper's 1.8 degree/step is also 200 steps per rotation.

    1000 RPM's would need a motor that could step at 200,000 steps/sec. A NEMA will not have that capability.
     
  3. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    It seems to me that achieving 1000rpm should not be that hard. The driver seems to be able to achieve the needed 3333pulses per second easily, and the motor should run fine with the proper voltage applied.
     
  4. araforn

    Thread Starter New Member

    Jul 26, 2011
    18
    0
    Thanks for the quick reply guys. Kubeek, how did you come up with the 3333 pulses per second needed for that motor?. I'm still unsure how to calculate the max speed.
     
  5. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    Well, 1000 RPM is 16.6 revolutions per second. You need 200 pulses per revolution, so 16.6*200 is 3333.3 PPS.
     
    araforn likes this.
  6. tracecom

    AAC Fanatic!

    Apr 16, 2010
    3,869
    1,393
    I think that high speed would be more achievable with coarse step motors, however even that is problematic.

    For example, I have a 15 degree motor, which translates to 24 steps per revolution. 1000 rpm is 16.67 rps, which translates to 400 pps for a 15 degree motor. This particular motor requires at least a 4 msec pause between pulses, or it may miss the pulse. 4 msec times 400 pulses is 1600 msec, so the pause requirement leaves less than no time for pulses of any duration.

    I have never tested this, but it may be that the coarser the steps, the longer pause that is required between steps. I have a 1.8 degree motor that can get by with 1 msec pauses between steps. I don't have the capabilities to pause less than 1 msec, so I don't really know its absolute minimum.

    It's an interesting question, but my very limited experience and my intuition tells me that a 1000 rpm stepper is extremely unlikely.

    ETA: Attached is a document which should help. At least it will give you some formulae with which to amuse your professor.
     
    Last edited: Oct 6, 2011
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