My design using treadmill motor

Discussion in 'The Projects Forum' started by shrydvd, Dec 21, 2011.

  1. shrydvd

    Thread Starter New Member

    Dec 21, 2011
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    I have a treadmill motor PMDC Motor C3364B3608 (2.80 HP @ 130 VDC / 2089 WATTS 1.75 CONT. DUTY @ 100 VDC 1305 WATTS).

    I want to use it to make my daughter a pottery wheel.

    Here is my plan & I would like to get some input (especially about whether or not what I am doing is safe).

    So far, I have put a transformer that dropped the voltage down to 12 / 24 volts depending on how I wire it. I wired it for 24.

    Next, I have a bridge rectifier converting to DC. This seems to be turning the motor quite well. One thing I am concerned about though is that I don't know how it will do under a load.

    My questions are:
    1. Is this safe?
    2. Is there more I need to do; is there a better way to do it?
    3. So far as a load goes, I can use pulleys to increase the torque. Is this the best way/only way?

    As you can probably tell by my questions and wording, I am very much a novice tinkerer. I just "learned" last night about bridge rectifiers. I was really suprised when I hooked all this up & it actually worked.

    Anyway, any help or advice anyone can give me (preferably in layman terms) would be much appreciated.

    Thank you all & Merry Christmas!

    David
     
  2. tracecom

    AAC Fanatic!

    Apr 16, 2010
    3,869
    1,393
    Answers to the following questions will be helpful to those reading your post. You are correct in wanting to be sure what you have done is safe, especially since there is water, electricity, and your daughter involved.

    What are the specifications/model number of the stepdown transformer?

    What are the specifications of the bridge components (diodes)?

    Do you have a schematic that you can post (even hand drawn)?

    Photos are always helpful.
     
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  3. shrydvd

    Thread Starter New Member

    Dec 21, 2011
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    Thank you for the reply Tracecom!

    I knew better than to post like that but I got in a hurry.

    Anyway, The following is the information you asked for.
    The transformer is SEC 12.6-0-12.6V 2A; Pri 120V 60Hz from Radio Shack
    The bridge is a Silicon Bridge Rectifier, 100VDC 1500 mA.

    After reading more I found that the voltage controlled the speed and the amps gave the torque. Therefore I tried using a Rosewill computer power supply (LPK8-400W). I used the 12v 15a yellow wire.

    Lastly, I also just got a 4 amp 400 volt Full-Wave Bridge Rectifier.

    [​IMG]
     
  4. strantor

    AAC Fanatic!

    Oct 3, 2010
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    alright, well your motor is rated 130V, 2089W. ohms law P=I*E, rewritten I=P/V, so 2089w/130V = 16A. but you're not running at 130V, just 24V (that's 18% of 130), so proportionally 18% of 16A = 2.88A. your rectifier is rated for 1.5A, so it is nearly half as big as it needs to be. it would probably smoke if you put a load on it. find a rectifier with lower voltage and higher amperage. And you transformer is only rated for 2A. I would put a 2A fuse on the secondary. it may turn out that your daughter doesn't have enough strength to load that wheel down enough to draw 2A.

    EDIT: just saw you got a 4A rectifier. good deal
     
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  5. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    One problem with a treadmill motor used for something like this is its RPM. At the rated voltage they are ~4000 - 6000 RPM. Running them at lower voltage, while they run slower they will start to develop 'cogging', instead of turning steady it will start to jump as each pole is activated.

    A good alternative may be to use a car wiper motor. It is geared down to ~45RPM. The gearing also increases the torque output of the motor. And before some one says- a wiper goes back and forth, the motor its self is continuous rotation. The back and forth comes from the linage to the wipers. :)
     
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  6. shrydvd

    Thread Starter New Member

    Dec 21, 2011
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    First I want to thank you all for your wisdom & time.

    Strantor: Thank you for the "ohms law". That is really cool & I can see applications down the road for it as well. I've been "bitten" by this project bug & can't wait to make more stuff.

    Shortbus: That is the ticket. I went to the neighborhood shade tree mech & got two wiper motors. I told my wife I needed two so I could tear down one to figure out, while I use the other. Truth is, I am learning I can never have too many parts. Long live Fred Sanford, my hero!

    I think the wiper motor is going to work. It is REALLY slow though. I wish I could speed it up just a hair. I am going to work on that now.

    Again, thank you all for all your help and Merry Christmas!

    Sincerely,
    David Collins
     
  7. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Most wiper motors have a slow and fast speed, just find the correct terminal. Welcome to AAC and Merry Christmas to you and yours also. I agree about never having too many parts! And watch out, making stuff is addictive!
     
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