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Simple Question Regarding Using Linear Motor

Question asked by David Maxham on Dec 28, 2009
Latest reply on Dec 30, 2009 by David Maxham

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I've been struggling with trying to get a linear motor to work in Motion Study. It's easy enough to insert one in the motion study, but when I run the motion study, nothing happens. I've searched for some time now for some information, but there doesn't seem to be a trace of information on how to properly activate a linear motor. I've looked at a working example that was posted here about 4 years ago and I notice that when I run that motion study, there's a yellow line that appears in the timeline. This yellow line is not present when I run my simple model. Is there something else that needs to be done to activate a linear motor?

Any help would be greatly appreciated.

Dave

John Sutherland Dec 28, 2009 5:54 PM

Correct Answer

The absence of yellow line confirms that there is no motion.

Probably you have made a logical error. e.g. the driven object is not free to move.

Or you have incorrectly specified the motor.

I suggest plotting Results on everything to provide clues.

See the reply in context

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David Maxham Dec 28, 2009 12:01 PM

Here's a link to a site that has a simple motion limiter, which works fine. I still can't figure out how to make a linear motor work. I've tried everything to make this simple model NOT work, but I can't make it NOT work. I was hoping that finding out what makes it not work, I could understand how to make a linear motor work.

http://www.mikejwilson.com/solidworks/solidworks_files.htm

Dave

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John Sutherland Dec 28, 2009 5:54 PM

The absence of yellow line confirms that there is no motion.

Probably you have made a logical error. e.g. the driven object is not free to move.

Or you have incorrectly specified the motor.

I suggest plotting Results on everything to provide clues.

Actions

David Maxham @ John Sutherland on Dec 28, 2009 6:18 PM

That's it! I don't know what I did wrong with my first attempt, but I started over again. Now that I understand what the yellow line means, I got the linear motor to work.

Thanks very much for your help - you've saved me hours of needless struggle! I can now spend my time exploring this motion-studies module to understand a brush-bounce situation with one of our starter motors.

Dave

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David Maxham @ David Maxham on Dec 29, 2009 8:38 AM

I think I know what was wrong with my original model. The component that I wanted to have moved by the linear motor needed to be floated.

Thanks again!

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John Sutherland @ David Maxham on Dec 29, 2009 5:27 PM

" I can now spend my time exploring this motion-studies module to understand a brush-bounce situation with one of our starter motors."

Oh dear! I hope you have lots of time.

Start by cranking Integration Frames Per Second up to 1000 in order to capture high speed action.

Do not rely on visual results but plot on one chart, parameters such as angular velocity and linear acceleration to show what is happening.

Your first run should have no motion excitation.

Duplicate that study and add only initial velocity.

Ditto and add rotary motor.

This is the sit, crawl, walk, run philosophy.

SolidWorks provides nothing for documenting your steps towards the point where you give up through exasperation.

I am using spreadsheets to collect and tabulate the hundreds of motion study settings, and for better control of plotting the results exported as csv files. This is a lot of manual work but necessary if you need to convince a sceptic of the validity of your results.

I have found no documentation for tasks as challenging as yours. If there is any then it is a well kept secret.

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David Maxham @ John Sutherland on Dec 30, 2009 11:04 AM

Thanks, I really appreciate the help.

I'm looking into the behavior of a starter motor's brush, and in particular, how the brush might bounce off the surface of the commutator. The brush is held down to the surface of the commutator with a coil spring that pushes on one end of the brush. We have a mock-up rig to represent the brush/commutator assembly and we are going to do some actual vibration studies with our in-house shaker table. So, I figured I'd try to model the actual test setup using Solidworks Motion Studies. I hope to figure out at what shaker-table-imposed frequency the brush starts to bounce off the commutator surface.

Anyways, I just thought I'd mention that in case anyone has experience using Solidwork's Motion to model such a behavior.

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6 Replies

David Maxham Dec 28, 2009 12:01 PM
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Correct Answer
Here's a link to a site that has a simple motion limiter, which works fine. I still can't figure out how to make a linear motor work. I've tried everything to make this simple model NOT work, but I can't make it NOT work. I was hoping that finding out what makes it not work, I could understand how to make a linear motor work.

http://www.mikejwilson.com/solidworks/solidworks_files.htm

Dave
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John Sutherland Dec 28, 2009 5:54 PM
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Correct Answer
The absence of yellow line confirms that there is no motion.

Probably you have made a logical error. e.g. the driven object is not free to move.

Or you have incorrectly specified the motor.

I suggest plotting Results on everything to provide clues.
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- David Maxham @ John Sutherland on Dec 28, 2009 6:18 PM
  Mark Correct
  Correct Answer
  That's it! I don't know what I did wrong with my first attempt, but I started over again. Now that I understand what the yellow line means, I got the linear motor to work.
  
  Thanks very much for your help - you've saved me hours of needless struggle! I can now spend my time exploring this motion-studies module to understand a brush-bounce situation with one of our starter motors.
  
  Dave
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  - David Maxham @ David Maxham on Dec 29, 2009 8:38 AM
    Mark Correct
    Correct Answer
    I think I know what was wrong with my original model. The component that I wanted to have moved by the linear motor needed to be floated.
    
    Thanks again!
    Like • Show 0 Likes0
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  - John Sutherland @ David Maxham on Dec 29, 2009 5:27 PM
    Mark Correct
    Correct Answer
    " I can now spend my time exploring this motion-studies module to understand a brush-bounce situation with one of our starter motors."
    
    Oh dear! I hope you have lots of time.
    
    Start by cranking Integration Frames Per Second up to 1000 in order to capture high speed action.
    Do not rely on visual results but plot on one chart, parameters such as angular velocity and linear acceleration to show what is happening.
    Your first run should have no motion excitation.
    Duplicate that study and add only initial velocity.
    Ditto and add rotary motor.
    This is the sit, crawl, walk, run philosophy.
    
    SolidWorks provides nothing for documenting your steps towards the point where you give up through exasperation.
    I am using spreadsheets to collect and tabulate the hundreds of motion study settings, and for better control of plotting the results exported as csv files. This is a lot of manual work but necessary if you need to convince a sceptic of the validity of your results.
    
    I have found no documentation for tasks as challenging as yours. If there is any then it is a well kept secret.
    Like • Show 0 Likes0
    Actions
    - David Maxham @ John Sutherland on Dec 30, 2009 11:04 AM
      Mark Correct
      Correct Answer
      Thanks, I really appreciate the help.
      
      I'm looking into the behavior of a starter motor's brush, and in particular, how the brush might bounce off the surface of the commutator. The brush is held down to the surface of the commutator with a coil spring that pushes on one end of the brush. We have a mock-up rig to represent the brush/commutator assembly and we are going to do some actual vibration studies with our in-house shaker table. So, I figured I'd try to model the actual test setup using Solidworks Motion Studies. I hope to figure out at what shaker-table-imposed frequency the brush starts to bounce off the commutator surface.
      
      Anyways, I just thought I'd mention that in case anyone has experience using Solidwork's Motion to model such a behavior.
      Like • Show 0 Likes0
      Actions

Simple Question Regarding Using Linear Motor

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