2.5 hp pmdc controller for mill

Discussion in 'The Projects Forum' started by weldstuff, Oct 29, 2013.

  1. weldstuff

    Thread Starter New Member

    Oct 27, 2013
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    Hi I'm new to this site. I've be reading everything I can about making a DC motor controller that will run a home built mill I'm making. I do gunsmithing work and I cut parts from sleel and aluminum, I don't have a lot of room in my shop for a bridgeport and all of the pieces I work with do not warrent such a large machine. I've tried the drill press thing with a x,y table, but I want to built something stiffer with, hopefully this 2.5 hp, 5600 rmp 120 vDC motor and all the controls that came from a working treadmill. I am searching for advice to either use the components I have, or to just buy a KBMM-125 or KBMD- 240? I understand enough about the circuitry to get me I trouble. My trade was a metal fabricator 40 yrs. Testing I have run this motor with a 5A Variac to bridge rectifier. I would run very smoothly slow to fast rpm, But I thought the torgue was missing when I put a load on it. It also popped a breaker when I loaded it with at slower rpm. I'm sure the 5 amp variac didn't like that either. I ve read on this forum or another someone telling someone to buy a KBMM PWM controller and it would pulse 120v dc to the motor varing the speed and torque would also be there at mid range rpm's. I looked into buying one on Ebay but the Kbmm-125 goes to 90v and the KBMB -240 is 230v and supplies up to 180vdc I my memory serves me. If I buy a KB, I still think I need a pot. and resistor and a fuse also? On the other hand, I may very well have all those goodies at my disposal and not know it, also not know how to configure them to make a controller. All I need is ON/OFF and varible speed. I have taken pictures of the components I have. I just have to figure out how to post them here. Hey got the pic's. Any advice appreciated, thanks Pat.
     
  2. wayneh

    Expert

    Sep 9, 2010
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    I guess I'm a little unsure what's wrong with just using the control system that came with the motor. Sorry if you said it already, I missed it.
     
  3. #12

    Expert

    Nov 30, 2010
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    I'm guessing you need about 12 amps of 120 VDC PWM, but I can't tell jack by looking at your photos. I can tell you that slapping 120 volts on that motor in short pulses will give you all the torque it was built for, and PWM is rather efficient. Can you tell how many amps it really uses as a start surge, at full speed with a proper load? Not without a controller, right? See any labels? Brand name and model number?

    strantor would be the guru for this one. Maybe he will notice this and pipe up.
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    That is one of the El-Cheapo model of a T.M. motor, some you have to watch as they are designed uni-directional, The Minarik drive you have there should work.
    With the KB models you have the option of SCR bridge or PWM, with the PWM obviously being a tad more expensive.
    The KB does require the Pot,fuse and current sense resistor to suit the motor.
    I am very cautious about the H.P.claims of the treadmill motors as they do not possess the same physical size as an equivalent industrial motor of the same rating.
    Incidentally, for a machine spindle application, it is normal to remove the flywheel on the motor.
    Max.
     
  5. weldstuff

    Thread Starter New Member

    Oct 27, 2013
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    I would like to use the parts that I need from it if I can get help from the forum with advice. The original touch board lights up for 2-3 seconds then goes off??? It won't run the motor. I got this stuff from a friend who took it all apart and left me hanging to figure it out on my own. I do not have the saftey start key so I stuffed some cardboard in the hole where it should go. Still won't run. Only way I got it to run is with the Variac and thru the bridge rectifier then straight to the motor. It also is too big with too many unneeded options on it. I think the way I have wired it its not using all the components it should to do what it should, I just don't know where the ac input should be where the pot should be where the dc out should be. Minor stuff like that. I would like to learn how it should be wired maybe with a pot added to the controller board. Pat
     
    Last edited: Oct 29, 2013
  6. weldstuff

    Thread Starter New Member

    Oct 27, 2013
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    #12 & MAX heres the motor info Weslo Inc. pt. no. 124184, by GS Electric mod.#B4cpm-0741...Rotation CW, 120VDC, speed 5600, treadmill duty. You're right about the unidirection.The flywheel is also the cooling fan. I was thinking on running the spindle with a pulley and belt from this motor. It has a 15amp reset breaker in the circuit, and a on/off switch.
     
    Last edited: Oct 29, 2013
  7. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Many of the T.M. controllers are soft start, IOW you have to take the pot or controller down to zero before you can increase the speed.
    Others are also PWM control signal rather than 0 to +10v. Pot.
    Are you sure that is the belt motor drive as it has Incline marked on it?
    Max.
     
  8. weldstuff

    Thread Starter New Member

    Oct 27, 2013
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    The flywheel has the belt pulley on the front side also. I'm sure its the belt drive motor. I'm sure the treadmill also had another motor for the incline but not this big. I never saw the TM in one piece I just got this basket of parts from a friend. The motor relly goes. It spins up like it doesn't have a flywheel on it. Thats with the Variac.
     
  9. MaxHeadRoom

    Expert

    Jul 18, 2013
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    No I meant is the Board intended for the belt motor you have?
    What also makes me think that is the lack of much logic on the board?
    The incline usually just works at one speed, there is not too much to the control.
    It may be worth looking at one of the KB/Baldor versions?
    Max.
     
  10. weldstuff

    Thread Starter New Member

    Oct 27, 2013
    7
    0
    I tried to clean up my pics.. removed wires etc. This is what I got to work with. Can I use the Minarik board and maybe add a pot to get the motor to work or should I just get a different controller (KBMM-125 ??? ) End result I just want a simple control when done with on/off and vari speed. Thanks Pat
     
    Last edited: Oct 30, 2013
  11. MaxHeadRoom

    Expert

    Jul 18, 2013
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    It appears that controller has momentary P.B. to increment the speed, there must be other logic in the head unit.
    The one problem with keeping the flywheel, you cannot do any drastic acceleration or you pop the breaker or fuse.
    The KBMM-125 is an enhanced KBIC-120 they are both SCR type drives, but they offer current limit and acceleration control.
    With the SCR types you get a little switching noise on the low rpm's that you don't get with the PWM type.
    If you want a little more performance and top speed, the PWM switching models such as KBCC type etc.
    Max.
     
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