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Discussion Starter · #1 ·
Hi all

I have acquired a treadmill, and taken it all apart, and I want to be able to control the speed of the motor using a potentiometer, rather then using the control panel. From this I am then hoping to put it to use in a machine.

I have a basic understanding of electronics, but I was slightly stumped when my controller used an Ethernet cable to the panel rather than a few wires.

I have attached a labelled photo of the controller, and hopefully someone can point out where about I need to put the potentiometer.

The treadmill was a J6F Tunturi treadmill, with a 130VDC motor. From prior research it appears it is likely to be controlled by PWM, but I am not sure.

Thanks for any help!
 

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Rick
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Welcome to the forum Matthew. I think your going to have a hard time getting a good answer to this one . I'm thinking your going to use it for a stationary belt sander ?

I think your going to need a schematic to get a better understanding of how the circuit works
 

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Found this on a home brew site,

"Go cheap look for a used 1, 1 1/2 or 2 HP threadmill motor as they come up as failed weight loss items even curbside finds. These motors have a LED shutter wheel for constant rpm control no matter the motor torque demanded.
This with the electronic set speed control panel you can build a solid rpm controlled high HP mill motor rather cheap or even free. These motors also have a flywheel with the fan as a cast unit plus poly belt drive. Run this to a jackshaft then to the mill removing mill bushing radial side loading, LoveJoy direct coupling. Function before money and beauty, JMO."


I dont think you will manage to make it work from a simple pot. controller.

So, when is the first batch of white lightning gonna be ready?
 

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Hi Matt and welcome. I would agree with Bob about the pot control. Too many circuits dependent on one another. Why not just take the control switch and add some wire so you can put it where you want and leave the rest alone?
 

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welcome to the forums Matt...
 

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Welcome to the forum, Matt. I think Charles has the easiest answer.
 

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It doesn't sound like you're going to be able to replicate the signaling coming out of the panel buttons with a potentiometer.

Maybe the answer will be in starting at the DC motor and collecting the parts and circuitry necessary to control the motor (brand new circuitry).

I'm assuming you're looking to keep the functions of the controller like speed and load control...?
 

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Discussion Starter · #8 ·
Hi

The issue with just using the control panel is that it brings up a lot of errors due to issues such as the incline motor not being attached. I suspect that I may have to follow Nickp's advice and build up from the motor, discarding the board.
My understanding was that there was a small voltage sent from the control panel to the motor control bit that altered the PWM with the change in voltage. Therefore a potentiometer could easily control this voltage. Although it seems the model I have may not be so simple.

Thanks
 

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So go ahead and reconnect the incline motor. That doesn't mean you have to use it. It's possible you would just need to replicate the resistance in the circuit but I'm certainly no expert.
 

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The problem will be speed control. On the motor itself is there a little metal disc with perforations around the edge of it, and a small arm with a magnet hanging over it? If so, that is the optical speed controller. As the motor spins, the gaps in that disc create magnetic pulses which are counted by the PCB. This is why you need the ethernet cable.When you change the speed control, the motor voltage is changed untill the magnet counts the number of pulses that the PCB is calling for, and then the PCB returns the voltage to stable.

Youll never get that accuracy with a simple potentiometer. How steady do you need the rpm to be?
 

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I can see one thing, all this went zooming waaaay over my head.

Matthew welcome to this forum. :smile:
 

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I can see one thing, all this went zooming waaaay over my head.

Matthew welcome to this forum. :smile:
don't feel bad...
you are not alone...
 

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Hi

The issue with just using the control panel is that it brings up a lot of errors due to issues such as the incline motor not being attached. I suspect that I may have to follow Nickp's advice and build up from the motor, discarding the board.
My understanding was that there was a small voltage sent from the control panel to the motor control bit that altered the PWM with the change in voltage. Therefore a potentiometer could easily control this voltage. Although it seems the model I have may not be so simple.

Thanks
Matt...it's likely that the control panel supplies a "signal" rather than a steady voltage that changes. I'm guessing that from the use of a chip on your board. I couldn't read the chip type so wouldn't hazard a guess as to how it receives signaling. If that is the case what you might need is more of a up/down momentary pulse to control the motor. If you can reconnect everything and monitor the signaling when you operate the control panel you might be able to deduce what you need to provide (for signaling) in place of the panel buttons. If you find that a momentary pulse of positive low voltage, for example, increases speed then check what the down button does (maybe a momentary negative low voltage) you could then replicate the panel buttons with a momentary DT switch (pulse-off-pulse).

All this is a bunch or pre-supposing, of course, and if this is the case you will then need to set the speed every time you power off - could become a pain...

Good luck...let us know...
 

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I have a background in electronics so here are my thoughts, hopefully this isn't over your head. The ethernet connector (RJ45) is probably not ethernet but rather a convenient connector for a custom protocol. If you have access to an oscilloscope or logic analyzer could could pretty easily figure out what the control signals are. The problem I would foresee is that the motor controller does the PWM and the control panel simply sets the speed. Then you would have to figure out the protocol and emulate it If you are familiar with arduinos, it would be relatively easy once you knew the protocol.
 
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