# Any DC motor engineer out there?



## Brakeman Jake (Mar 8, 2009)

I have a fair understanding of how DC current works,being familiar with voltage,wattage,amperage,polarity,etc,but that's just about it.I've spent most of my working years installing equipment on trucks and cars and have learned what I know getting my hands dirty.I have no engineer degree of any kind.

I've successfully installed a few Tsunami decoders and have learned a lot (still short of a lot though) about programming them but I'm stuck on something that,being honest,I don't understand.Soundtraxx calls this "Advanced Motor Control Features" (CVs 209 through 214).They use technical terms I don't have a clue what they are and,worse,explain them with terms only a tech guy understands.Here goes...
CV209 Kp coefficient,CV210 Ki coefficient,CV212 Motor Control Intensity,CV213 Motor Control Sample Period,CV214 Motor Control Sample Aperture Time....what these terms mean in a language most can understand?And what each does to a motor?Pros and cons?

In their explanation of what these are,Soundtraxx use terms like gain factor,PID,motor control equation,control loop,etc.

All terms I could use if I wanted to impress a gal at a bar,but are useless to me (and many others I guess).I've never messed with these CVs yet,and luckily my loco run fairly well with the default settings,but I'm aware I may be able to improve them if I only knew what can be done.

Any body knows of a book,website or else that explain this in a language a non-engineer can understand?Thanks.


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## golfermd (Apr 19, 2013)

If we did that then all of us engineers wouldn't be able to keep out jobs.


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## dannyrandomstate (Jan 1, 2012)

You lost me at CV.

Maybe a call into their tech line?


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## ggnlars (Aug 6, 2013)

What they are really talking about are damping factors on a vibratory system. The decoder pulses the motor very rapidly. It does this to get and give info about the motor speed, etc. This creates a classic vibratory system. 

In order to keep it stable and to achieve the control that is desired, there is a damping strategy. This involves several aspects of the problem. While the decoder manufacturers put different emphasis on these factors. They are attempting to do the same thing, provide stable motor control. 

Because each modeler wants his loco's to run differently over speed range, the decoder manufactures give you some variability in these coefficients and factors. While it is in fact fairly complex, think of it as being able to change the size and strength of the springs on you car. A decoder is a very smart device and it will do everything it can to keep the motor running. 

The CV inputs give you some control on how it does this. That is particularly important when your trying to run loco's together. No two motors will run the same and these inputs allow you to taylor how they will run to have a better match. 

I hope this helps,

Larry


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