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Dc Motor Drive Basic Questions

Discussion in 'ELECTRICAL ISSUES - POWER YOUR MACHINES & SHOP' started by calstar, May 10, 2016.

  1. calstar

    calstar United States Active User H-M Supporter-Premium

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    Very basic questions here. Picked up what a appears to be a good quality made in USA DC motor from a treadmill and want to use it on a lathe, here are the specs:

    IMG_8899_zpskfe0t6x0.jpg

    I want to use a MINARIK model MM23001C. adjustable SCR speed controller on the motor, here are its specs:

    Screen%20Shot%202016-05-10%20at%2010.27.26%20AM_zpsrm5azgqw.png

    First question, the controller specs show Armature voltage (115 VAC IN): 0-90 VDC and Armature voltage (230 VAC IN): 0-180 VDC . My motor shows 120VDC but I'm nearly positive it was used on 115AC to run the treadmill(and not 230, is this right?). Will the motor only run on 230VAC?

    Second question, is the motor rating of 2.75hp to much for the controller (as it's specs show only up to 2hp)?

    I've tested the motor using a 12v drill battery and it runs fine, if this controller will not work what are other options available that will? I want to use use a DPDT off center switch as well as a main off switch and a potentiometer.

    Another option is to use the original controller which seems to be in good condition(I removed it with the motor from the treadmill at the scrap yard) but don't know how to test it. Could I run 115ac to the controller(AC input in upper left corner of pic) with the motor connected to it or is that a bad idea(don't want magic smoke escaping:apologize:)? It seems like the Minarik will be an easier install, I can at least make sense of the installation diagram, but maybe using the original won't be so difficult once I have a better understanding of it. Here's a pic of the controller, the AC in is in the upper left corner.

    Screen%20Shot%202016-05-10%20at%2011.16.08%20AM_zps1xmwekif.png

    thanks in advance for any help,

    Brian
     
    Last edited: May 10, 2016
  2. British Steel

    British Steel United Kingdom Active User Active Member

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    The problem is going to be that the Minarik controller is only rated for 10 Amps, the motor pulls 20 at full load...

    The original controller should be rated for full load, but it's hard to see how its external controls should connect - there seem to be several small multi-way connectors on the board, you may need to look at what was originally plugged in where, and work from that?

    Do you have the rest of the treadmill's electrics, and can you post a (higher-resolution) close-up of the controller PCB so folks can maybe read the labelling on the connectors?

    Dave H. (the other one)
     
  3. Kernbigo

    Kernbigo United States Active User Active Member

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    use the thread mill controller and it will work ok, to many amp for the Minarik
     
  4. John Hasler

    John Hasler United States Active User H-M Supporter-Premium

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    It'll work on 120VAC.

    You could set the torque control on the Minarik to limit the current to 10 amp but that would be sad: you'd be giving up half the capability of that lovely motor. Get us more pictures of the controller. How many wires come off the motor? Did you get all of th electronics and cabling?
     
  5. calstar

    calstar United States Active User H-M Supporter-Premium

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    The controls for the treadmill(parts that the walker/runner uses) weren't with it, I got everything that was there. I'll take pics of the control board tomorrow and p0st them here. It would be nice to have the full load 20amp capability but even limiting it to 10amps would probably still be better(more torque?) than the 2hp 220AC motor that was on it. Here is a link to the set up I'm looking to have or something similar, I have the same lathe.
    http://rvbprecision.com/garage-entertainment/metal-lathe-dc-motor-conversion-jet-12-x-36-bd.html I believe this fellow is a member here but don't recall his forum name. He states his 3/4 hp 90VDC motor is plenty strong for the work he does, so as I said above I could live with the 10amps route.

    thanks, Brian
     
  6. xman_charl

    xman_charl Active User Active Member

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    Have used those controllers from surplus center. Work okay.
    Controller has jumpers, 90 vdc, or 120 vdc.

    3/4 would be okay, that treadmill motor would be overkill.


    my 2 cents


    Charl
     
  7. calstar

    calstar United States Active User H-M Supporter-Premium

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    Thanks Charl, thats what I was thinking after reading RVBprecision's mod page. I contacted one of the vendors for the Minarik, Galco, they had a controller that would give me 15amps but it was $380, too spendy for me. Here are the pics I took of the controller, might need a few more to cover it all, also includes diagram that was on the motor cover. The upper PCA was not there, it was cut at the serial interconnect cable but I do have all the wiring and pic of what went where. I'm not against using the controller if its possible, but couldn't do it without some step by step help, thats why I'm leaning toward the Minarik.

    This is probably way over simplified but.......couldn't I put a simple on/off switch on the line cord and a dpdt switch in the red/ black, for foward/reverse, to the motor from J6 in the diagram and also a potentiometer after the dpdt on the same black/red to the motor? Just throwing it out there, not concerned showing my lack of knowledge:)!

    thanks, Brian


    IMG_3778_zpscsyzpkso.jpg

    43a953fb-b523-45e3-92b8-7e397b4a018f_zpsmcapnfjr.jpg

    IMG_8917_zpswp4ekuhb.jpg

    IMG_8916_zps1a6rroz0.jpg

    IMG_8915_zpsfcfrhqdj.jpg

    IMG_3780_zpszgqqwxld.jpg

    15b8d9d1-a444-413a-81ab-a91121da68a0_zpsbwu4qwuu.jpg

    IMG_8919_zps7otkk0p5.jpg

    43a953fb-b523-45e3-92b8-7e397b4a018f_zpsmcapnfjr.jpg

    IMG_8917_zpswp4ekuhb.jpg
     

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    Last edited: May 11, 2016
  8. John Hasler

    John Hasler United States Active User H-M Supporter-Premium

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    J5 (which I can't find in the photos) is the key. The controller gets commands via a serial digital link to the micro in the front panel.
     
  9. calstar

    calstar United States Active User H-M Supporter-Premium

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    Thanks John, J5 is right above R11 on the right side in the pic below, I stuck the cut end of the serial connecter in it so the J5 is hidden, but its the "grey box" right above R11.

    IMG_8915_zpsfcfrhqdj.jpg

    I can take a pic of it tomorrow along with some info printed on the cable.

    So where do I go from here?

    Brian
     

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  10. calstar

    calstar United States Active User H-M Supporter-Premium

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    Here are the pics of the pin connector, J5, and the cable.

    Brian

    IMG_8938_zpsawjrn5ia.jpg

    IMG_8936_zpsky08mbby.jpg

    IMG_8935_zpsw2bxyvjt.jpg
     

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  11. British Steel

    British Steel United Kingdom Active User Active Member

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    From here, best place to go is where you got the motor and controller, see whether they still have the control head with the keypad...

    That's a serial connection, so (unless anyone knows better) the board's expecting codes, not simple voltages - I use a similar board from a Reebok treadmill, it too uses a serial link so I've had to keep (for now) the display and pushbuttons to use it as a DC motor test rig :(

    Otherwise - the board's a decorative ornament, nothing more, you may be best getting a KB or similar motor controller to replace it?

    Dave H. (the other one)
     
  12. John Hasler

    John Hasler United States Active User H-M Supporter-Premium

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    I wouldn't say that. The power devices could be salvaged.
     
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  13. calstar

    calstar United States Active User H-M Supporter-Premium

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    The control head and keyboard were not with the motor at the scrap yard so...... The Pacific Scientific motors with high amp ratings are pretty common from looking at ebay, the downside is no one makes a controller for them that is in the price range of the Minarik ($100+-). I've spoken to a rep from Galco and Minarik itself, but if the motor is higher than 15amps and 115ac input controllers are not readily available. I asked the Minarik rep about using the Minarik 2300 series and using the voltage limiter to keep the power at 10 amps, he seemed to think it was risky, the controller still might get fried. I don't know if the this motor on my lathe would ever get close to overload but I doubt it(right?).

    Looked at the KB controllers as well, they have models with fuses. Could I use a lower rated fuse so it would blow if an overload(above the 10amps) was sent to the controller? I will talk to KB about this.

    Edit: just got off the phone with KB tech, he seemed to think that by limiting the motors start acceleration to a slow ramp up speed it would greatly decrease the chance of damaging the controller(KBCC125)k, thoughts?? Of course no guaranties using this.
    link to KBCC125
    http://www.galco.com/buy/KB-Electro...xjsuVyb0fNil6A6x9-aRgcV2wV26-FGk8IaAtmQ8P8HAQ

    Any input is always welcome,

    Brian
     
    Last edited: May 13, 2016
  14. LucknowKen

    LucknowKen Active Member Active Member

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    You have the motor with the original controller.
    Perhaps i am misunderstanding but why do you require the "control head and keyboard"?
    I have 4 TMMs on the shelf with the circut boards, and the slider for the variable speed control.
    The user console has nothing worth salvaging. Just mho.
     
  15. brino

    brino Active User H-M Supporter-Premium

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    Hi Ken,

    On your motors/controllers the speed control is a simple slide pot.

    On Brian's they used a digital serial interface between the user touch-pad and the motor controller circuit board. Who knows what the protocol of those serial messages is and how to "fake" them?

    I am currently facing the same problem with the treadmill parts I just picked up this week. I did get the entire machine and therefore have the touch-pad too, but it is unclear how to use the motor and controller without the touch pad. I hope to have a closer look at the works this weekend and try to determine if/how I can make these parts work for my project. I would prefer to lose the serial control interface and find a way to wire in a simple speed pot.

    -brino
     
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  16. calstar

    calstar United States Active User H-M Supporter-Premium

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    Thanks for answering the question! Brian
     
  17. LucknowKen

    LucknowKen Active Member Active Member

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    Hey guys: Thanks for the info. The Johnson motor i have (pictured) indeed has a console with ribbon cables.
    Two cables leading to two touch pads, one pad for speed the other incline.
    12 settings or buttons each side. 10 leads on each ribbon.
    Johnson.JPG Minarik.JPG
    I better hang on to the console.
    Lken
     
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  18. Bi11Hudson

    Bi11Hudson United States Artificer00 H-M Supporter-Premium

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    First I would warn you off of a "potentiometer" for speed control. It actually would be a rheostat and have to carry motor current. 10 Amps is a pretty big rheostat, especially when you would have to purchase it. And it gets very hot while running slow.

    The motor alone will run at base speed with no more than a rectifier in the line side.(preferably a bridge, about $7US) A reversing switch would be the DPDT switch, preferably with a center off position as well. The rectifier will be about an inch and an eighth square. It should be rated well above what the motor pulls. 40 Amp at 600 Volt is a stock item in my shop for similar applications. We are dealing with line voltage here. See an entry in the shop electrical/wiring section for a link.

    Now, to speed control. A little(?) research will be in line. If it was me(!), I would use a high current pass element as the main element with a lower current controller. A model train power pack is a good starting point, but with much higher current capacity. They're only rated for a couple of amps. A good choice here would be 2N6284 and 2n6287 to build a bridge amplifier. Rated at 20 Amps continuous and 40 Amps surge. With, of course, a good heat sink.

    If you get the controller board up and running, that would do for speed control. If it was mine, I would start from scratch and make my own (simpler) version. Everything recent is made computer control for cost and simplicity of manufacturing purposes. Since politics are "verboten" here, I won't go into that subject any further.

    The motor is just a motor. In this case, applied voltage controls the speed. The big issue to note is that torque falls off at a distressing rate as speed is reduced. I'm babbling now, hope this gives some direction to your search.
     
  19. Kernbigo

    Kernbigo United States Active User Active Member

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    You are over think this i have done several of these, get tread mill speed control off ebay, m60 which is big enough to run that motor, a lot cheaper and it works good.
     
  20. FanMan

    FanMan Active User Active Member

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    Figuring out the serial protocol could be quite the task unless you're experienced in that kind of thing and have the necessary test equipment. As others have said the Minarik speed control isn't sufficient; I would look for an MC-60 treadmill controller on ebay... cheaper than the Minarik and sufficient capacity. All you need is a potentiometer with the MC-60 to set the speed. Or an MC-2100 controller, though that's somewhat more difficult to interface with as it requires a PWM signal to set the speed. Fortunately others have done that work already, info in the thread I started recently.
     
  21. markba633csi

    markba633csi United States Active Member Active Member

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    Really the only thing limiting the KB (or Minarik, or Dayton or Dart) controllers is the SCR ratings and the heatsinking. Of course you'd have to have a proper sized "horsepower" (current sensing) resistor but essentially that's it. Oh, and the bridge diodes. You can get I think up to 40 amp devices in tab style TO220 packages.
    Mark S.
     
    Last edited: Mar 1, 2017
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