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Thread: How to use a potentiometer with this treadmill motor and speed controller?

  1. #31
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    Sorry for the resurrection, but I've been working on setting up an MC-2100 control board for my old manual lathe. In the process, I goofed and shorted a couple of the input wires together last night, and smoked the R2 resistor. I'd like to replace it, but can't read the color bands any more cause they're all black... Any chance one of you guys could take a look and tell me the proper value? Thanks in advance!!

    Here's the resistor I'm talking about:


  2. #32
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    OK .. here .. I'll share this with you .. this isn't just a 2100 schematic .. it's the 2100
    reversed engineered. You won't find this anywhere else.

    http://www.mikeamick.com/misc/MC2100_rev_engrd.pdf

  3. #33
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    Quote Originally Posted by macona View Post
    An arduino for this????

    A 555 is all you need, or a SG3524 PWM chip.
    Some people just have to use a "computer" to do what a simple bit of logic
    will do. :-)
    ...lew...

  4. #34
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    None of the chips mentioned can be 'just hooked up to a pot' etc and do the job. They all need support components and a circuit developed. The 494 is meant as the heart of a switch-mode power supply, though it could be wired up as a simple PWM circuit. Same for the 3524 and any other chip meant for switch-mode power supplies. If you're going to develop the circuit from scratch, you will need electronic knowledge and experience at building electronic circuitry, etching pc boards, etc. The 555 is probably the easiest to use in this regard, as it has fewer pins to have to deal with, and requires the least amount of support components.

    It would help to lay out the needs in plain language. First, you have a dc motor that you want to run at a variable speed. Secondly, the power source generally available to run it is 110vac. There's the power side of the circuit, then the control side. The power side is the ac input voltage- this you need to convert to dc, so you feed the ac into a bridge rectifier and filter capacitor. Then you need to control this power with a device capable of handling the voltage and current. This device may be a bi-polar power transistor, it may be an insulated gate bipolar power transistor, it may be a mosfet device. Where the input power doesn't need to be smooth dc, this power device could be an SCR or a TRIAC.

    Now this device needs to be controlled, so this is where the PWM generating circuitry comes in. This circuitry needs to be powered in order to function, so a separate low level dc power source is usually needed. This could come from a wall adapter, it could be from a built-in transformer, rectifiers and filter, maybe with a regulator (essentially a wall adapter, but built into the box instead of separate) or it could be developed from the rectified ac voltage in the power stage. The point is though that it is needed, so some circuitry has to be developed to supply it.

    Then the control signal has to be developed. This is where the chip comes in, whether it's a 555, a 494, a 3524, or some other chip that can be configured to produce a variable pulse width. The users control is the pot and probably some switches. The output from the PWM generating circuitry has to be optimized to properly control the power device. There is no such thing as a simple 'plug-n-play' here.

    Because you're dealing with fairly high voltages and fast switching speeds, motor inductances, etc, you will need to add components to keep the waveforms under control so the circuitry will operate properly without mysteriously burning up.

    While the total of the circuitry may be relatively simple as compared to other electronic items, it is not simple to develop from scratch. The best you could hope for is that someone has developed it already, and you could either buy the kit and put it together yourself, or you buy it already made. Several of you have mentioned model numbers, etc of the different drives available which are ready to go and work well. For 99.9% of us (myself included, with my decades of electronic knowledge) the smart thing to do would be to simply buy a controller. I could build one, but it's far from being a time-effective thing to do, although I often get immersed in these things. Seems I'm one of a rare breed who likes to 'entangle himself in yards and yards of wire' as they say- but the decision to 'build it myself to save money' is not smart. It might be the perusal of a hobby to do it myself, which is fine, but it's not the efficient way to cater to the requirement of
    getting the machine up and running.

    As can be seen, the statement 'all you need is a 555' leaves out a lot. It's true that you don't need a chip any more complex than that one to generate the variable waveforms needed, but it's obviously far from the whole picture. I'm as guilty as anyone for making that type of suggestion, especially when virtually everyone who would be reading this would be lost when it comes to actually developing all the circuitry and amassing all the proper components to make the actual function required into a reality.

    Not trying to be a party pooper, just bringing a little realism into the picture.
    Last edited by darryl; 09-17-2012 at 09:32 PM.

  5. #35
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    Quote Originally Posted by mikeamick View Post
    OK .. here .. I'll share this with you .. this isn't just a 2100 schematic .. it's the 2100
    reversed engineered. You won't find this anywhere else.

    http://www.mikeamick.com/misc/MC2100_rev_engrd.pdf
    This is amazing. I love the internet.

    Thanks for taking the time to create this, and then being willing to share it. I truly appreciate it.

  6. #36
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    Sure Schoolie ..

    Although I do have a 2100 in my junk pile .. I usually use other controllers that you only
    need to add a pot to make it work. This diagram was made by a Phd Scientist friend of
    mine that was determined to figure out the 2100. And yea .. he did a heck a of job.

    Good luck on your project.

  7. #37
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    Quote Originally Posted by mikeamick View Post
    Sure Schoolie ..

    Although I do have a 2100 in my junk pile .. I usually use other controllers that you only
    need to add a pot to make it work. This diagram was made by a Phd Scientist friend of
    mine that was determined to figure out the 2100. And yea .. he did a heck a of job.

    Good luck on your project.
    Mike, I've just about got the final version of my circuit working, that schematic has been very helpful in troubleshooting/tweaking as I mess things up, lol.

    Would your friend mind if I shared the schematic? I'm doing a writeup on the circuit I came up with, and would love to include all the info I can. I'd reference him, of course, assuming he provided some info to track back to him.

    Thanks again!

  8. #38
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    whoops .. missed a whole page of posts .. ahahahah ... disreguard this whole msg ..
    Last edited by Mike Amick; 10-29-2012 at 05:07 PM.

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