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Voltage controlled DC motor controller?

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acetm

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Hey all, this is my first post. I'm working on a project where I have an adjustable DC 0-12v 500mA power source which is used to control a model train motor on a miniature railroad. The control board/power source also has speaker outputs for realistic sound effects like engine RPM sounds which increase as the output voltage is increased.

I am working on a much larger backyard, rideable railroad and the train is powered by a 12v 150w 10a DC motor. I am installing an amplifier and speakers and want to use the same control system (built for small trains) for the realistic sound effects. Because it is only designed for low current uses, I need some sort of motor controller which will take the low current 0-12v voltage input, then take power from an external 12v power source and adjust that to control the speed of the larger motor accordingly. If someone can point me in the right direction, I'd appreciate it!
 

Tony Stewart

Well-Known Member
Most Helpful Member
I would choose something like this motor speed control which will deliver the torque you need.

, get two , they are cheap for spare parts.

You provide the panel or box and car battery with trickle charger.
https://www.amazon.ca/uniquegoods-C...f=sr_1_19?s=hi&ie=UTF8&qid=1470768763&sr=1-19

You will need a 10A DPDT switch if you want to reverse motor polarity for direction.

** actually a 20A switch or relay for direction using motors if you forget to turn off voltage before changing direction, which is bad form!
 
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acetm

New Member
I would choose something like this motor speed control which will deliver the torque you need.

, get two , they are cheap for spare parts.

You provide the panel or box and car battery with trickle charger.
https://www.amazon.ca/uniquegoods-C...f=sr_1_19?s=hi&ie=UTF8&qid=1470768763&sr=1-19

You will need a 10A DPDT switch if you want to reverse motor polarity for direction.

** actually a 20A switch or relay for direction using motors if you forget to turn off voltage before changing direction, which is bad form!
Now where exactly would I hook up the + and - outputs of my small controller to the input on that controller?
 

Tony Stewart

Well-Known Member
Most Helpful Member
you would not use your controller as it is not compatible with PWM This is your new controller.
 

spec

Well-Known Member
Most Helpful Member
Hey all, this is my first post. I'm working on a project where I have an adjustable DC 0-12v 500mA power source which is used to control a model train motor on a miniature railroad. The control board/power source also has speaker outputs for realistic sound effects like engine RPM sounds which increase as the output voltage is increased.

I am working on a much larger backyard, rideable railroad and the train is powered by a 12v 150w 10a DC motor. I am installing an amplifier and speakers and want to use the same control system (built for small trains) for the realistic sound effects. Because it is only designed for low current uses, I need some sort of motor controller which will take the low current 0-12v voltage input, then take power from an external 12v power source and adjust that to control the speed of the larger motor accordingly. If someone can point me in the right direction, I'd appreciate it!
Hy acetm,

Welcome to ETO. I see you are from the US. Care to tell us which state and put in your user window at the left of your posts.

Here is a circuit to do your job. The PMOSFET will need to be mounted on a substantial heatsink using a TO220 mounting kit and an aluminium oxide insulating washer (not mica or plastic).

spec
2016_08_09_!ss1_ETO_MODEL_TRAIN_CONTROLLER.png
 
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acetm

New Member
Hy acetm,

Welcome to ETO. I see you are fom the US. Care to tell us which state and put in your user window at the left of your posts.

Here is a circuit to do your job. The PMOSFET will need to be mounted on a substantial heatsink using a TO220 mounting kit and an aluminium oxide insulating washer (not mica or plastic).

spec
Hey, thank you so much for taking the time to draw up the schematics! Unfortunately I have very little knowledge of these circuits and I'm not sure it's something I could build myself. Could you recommend something already assembled?
 

spec

Well-Known Member
Most Helpful Member
Hey, thank you so much for taking the time to draw up the schematics! Unfortunately I have very little knowledge of these circuits and I'm not sure it's something I could build myself. Could you recommend something already assembled?
OK, I will give it some thought.:)

spec
 

acetm

New Member
OK, I will give it some thought.:)

spec
I suppose the other option could be just hooking up a servo to the small controller's motor output and then to the potentiometer on the above motor controller. Not the most efficient. Forward and reverse functionality would require some complicated gearing.
 

spec

Well-Known Member
Most Helpful Member
you would not use your controller as it is not compatible with PWM This is your new controller.
Tony,
Your PWM can operate from an external 0V to 5V signal. It would just be a matter of adding a couple of resistors to the input and the PW controller would work off the original linear controller.

spec
 
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spec

Well-Known Member
Most Helpful Member
I suppose the other option could be just hooking up a servo to the small controller's motor output and then to the potentiometer on the above motor controller. Not the most efficient. Forward and reverse functionality would require some complicated gearing.
See my post #11
 

Tony Stewart

Well-Known Member
Most Helpful Member
I **need** to use the old controller. Not having the sound and wireless computer control is not an option.
then you might need to find someone to figure out out to reverse engineer what the pot does on this controller and customize the interface to Be compatible. This is the cheap solution, but requires someone with a scope at your end.

Your wireless to hardware interface and this controller's pot for power control is an unknown.

It could be as simple as spec has suggested or something else.
 
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spec

Well-Known Member
Most Helpful Member
So I would just need a resistor to limit the output voltage of my small controller to 5V then I could hook it up to the largr motor controller in place of the potentiometer?
Yes, that is what I am suggesting. Like the diagram below:

spec

PS: don't worry about reversing the motor for the time being: that can be done with a simple switch.

2016_08_10_!ss1_ETO_MODEL_TRAIN_CONTROLLER_VER2.png
 
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