Synchronized opposing motors

Discussion in 'The Projects Forum' started by BPG, Apr 3, 2014.

  1. BPG

    Thread Starter New Member

    Apr 3, 2014
    4
    0
    Hi all,

    So I am wanting to build something I saw today. Some one built a 5 foot kaleidoscope that consisted of two stained glass pains that rotated opposite of each other and then it had a back light to shine through the pains as they rotated.

    I am interested I trying to make something like this, but a bit smaller for now. I am not sure how they had there drive system working to allow the opposing rotation of the glass.

    My idea was two wire two motors in series and face one opposite from the other to allow for the opposing rotations of the glass. I also need the motors to be in fairly synchronous rotation as well. Do I need two synchronous motors to accomplish this or will just two regular ac motors in series will work?

    I want to stick with ac also to allow for using a dimmer as a veritable speed control as well. This is all very rough and need some help working it to a working model.
     
  2. BPG

    Thread Starter New Member

    Apr 3, 2014
    4
    0
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,571
    2,382
    Generally the only simple way is with stepper motors, they can be synchronized by using the same pulse train to each.
    With servo's you would need a more sophisticated controller such as a motion card that is capable of servo gearing, i.e. track one motor of off another via the encoder.
    Motion cards such as Galil Motion can do this.
    Max.
     
  4. BPG

    Thread Starter New Member

    Apr 3, 2014
    4
    0
    Thank you for the reply. I haven't messed with steppers before. Do they hook up via a regular plug for single phase 120v or do they need a controller as well.
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,571
    2,382
    You require a controller, they are generally low voltage high current and use a step and direction pulse train, which has to come from or be generated from a dedicated controller or circuit.
    Max.
     
  6. BPG

    Thread Starter New Member

    Apr 3, 2014
    4
    0
    I'm sure the glass panes can be heavy, are the steppers fairly durable for such an application?
     
  7. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    That kaleidoscope is quite beautiful; I'd like to see more details about it, and the kaleidoscope in action.

    The most simple way I can figure to rotate the panes in opposite direction would be to use a low HP motor that has a gear reduction unit with two flat belts. The output shaft of the gear reduction unit would be not quite perpendicular to the rotational planes of the rotating panes.

    The output shaft will have two slightly crowned pulleys for the flat belts to ride on; this will help to keep the belts tracking in the center of the pulleys. One belt loops around one of the panes and an output shaft pulley; the other belt makes a figure '8' around the other pane and the other output shaft pulley.

    The figure 8 causes this second pane to rotate in the opposite direction from the first pane; if the two motor pulleys are the same diameters and the pair of panes are the same diameters, the speed of rotation of the panes will be approximately the same.

    I have a support method in mind for the two panes, but it would require at least 10 bearings supported by some kind of framework, and it's too late in the evening to think about drawing something like that.
     
    Last edited: Apr 6, 2014
    BPG likes this.
  8. wayneh

    Expert

    Sep 9, 2010
    12,156
    3,064
    Take a look at how a dryer drum is supported and rotated in a front-loading dryer. The weight is supported primarily by a few "wheels", and the drive belt is run all the way around the perimeter. I think that might work for this application as well. Or, turning one of the support wheels instead of using the belt is another option.

    As long as the two panes rotate at a similar rate, I don't see any need for synchronizing them. In fact it will appear more "random" if the patterns don't always repeat at the same clock position.
     
  9. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    Agreed. I would consider using two motors and two individually adjustable speed controls.

    You could play with the two speeds and find some really cool beat frequencies of the light patterns.
     
Loading...