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Running a DC motor using PWM

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  • Member since
    June 2009
  • 2 posts
Running a DC motor using PWM
Posted by watashiwa46 on Thursday, June 18, 2009 11:43 AM

       I have been attempting to run an "N" locomotive using a micro controller, driving (my own design) an "H" bridge.  At first I was able to get the engine to move rather slowly and smoothly.  Now it seems to sit and shutter at the same input as before. 

        The engine is about 15 years old, but has not been run that much.  If my engine was NOT made to run with PWM, will I damage it by continuing.  Would a new engine, that is DCC ready, be better to experience with.   Any help will be appreciated.  

         The "H" bridge switches 12 vdc with a duty cycle of less then a 1/3 to about 1/2.  As I don't have a scope (yet) I don't know the rep rate.  Is there a preferred value I should use.

  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Thursday, June 18, 2009 12:05 PM

The below photo is the output of a SoundTraxx Micro-Tsunami decoder controlled by a NCE Power Cab at speed step one. I did this with a can motor and a fifteen year old open frame motor. The pulses just get wider as I increase to speed. I would strongly suggest getting a 'Scope if you are going to be developing your own system. The 'Scope is not very expensive. You could probably do this with a application using your PC sound card as the DCC frequency is not very high. Search Google for PC used as an Oscilloscope.

  Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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