Sharing a 24v power supply

Discussion in 'General Electronics Chat' started by araforn, Aug 26, 2012.

  1. araforn

    Thread Starter New Member

    Jul 26, 2011
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    Hi all.

    I have 3 stepper motor drivers that control the 3 axis of a project I'm building. Each driver needs its own 24v power supply for each motor but I'm just wondering if it is possible to use a single 24v power supply and share it between the 3 drives.

    This may be a stupid question but it is one that I have been wondering about lately.

    Thanks in advance :)
     
  2. ramancini8

    Member

    Jul 18, 2012
    442
    118
    It depends on the current required by each stepper. Also, When the motor steps it might pull the 24 volts down, and that could cause interaction between the motors.
     
  3. #12

    Expert

    Nov 30, 2010
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    Translation: Only if the power supply has enough current and you allow for surges by placing capacitors near the fast switching devices.
     
  4. araforn

    Thread Starter New Member

    Jul 26, 2011
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    There are actually current settings on the drivers. Using dip switches, the current can be set. I wonder if this would allow me connect a higher current supply without the risk of burning out a single motor motor when it's on on it's own.
     
  5. #12

    Expert

    Nov 30, 2010
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    So you think a supply that can provide a lot of current might force extra amps through the motor...

    You should go to the "Chat" page where your question is posted, look at the top of the listings, and find "Ohm's Law for Noobies". Then, read it.
     
  6. jwilk13

    Member

    Jun 15, 2011
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    Your phrase of the day :p
     
    #12 likes this.
  7. #12

    Expert

    Nov 30, 2010
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    Some days we get a parade of people that think amps force their way into things:rolleyes:,
    and that is exactly why I wrote Ohm's Law for Noobies. The best part is that the agressive amps are addressed in the first few lines. They only have to read the whole 2 pages if they want to.
     
  8. ramancini8

    Member

    Jul 18, 2012
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    #12---your post is not completely correct. Even the addition of a large capacitance to the power supply may not allow three steppers to work from the same power supply unless the cap's esr is low enough to charge and discharge between step pulses. A high current power supply may be needed.

    Araforn, stepper motors require enough energy rotate the motor. Energy is the power EI and the time the power is applied. You really should read the stepper data sheets to to find out what can be done. If you can't read the data sheets because of your technical level, I recommend that you experiment by hooking up one motor, then 2 motors, then 3 motors and observe the results.
     
    Austin Clark likes this.
  9. #12

    Expert

    Nov 30, 2010
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    I didn't say, "large capacitance to the power supply". I said, "near the fast switching devices". And, I stuck my nose in because I could figure out what, "could cause interaction" means, but I'm afraid the original poster might go off in the wrong direction wondering about which of many interactions you might be suggesting.

    If I read the clues right, you're a world famous author and I'm a bit smarter than a truck driver. I can just about figure out engineer speak, most of the time. A fair percentage of the people that ask questions here aren't even as educated as I am, and some of them are struggling to be understood in a language they find foreign. I'm afraid you're going to go right over their heads. I'm also afraid you're going to feel I'm intrusive (and that could cause interaction).

    One of the things that makes a forum work is that different people say the same thing in different ways. I've seen it work so many times! Several of us take a shot at a question and the original poster eventually gets the "Aha" moment. That's what really matters to me. Being completely correct is usually not achievable in a single post. We are partially busy trying to find the level of expertise of the original poster. Details are often left out until communication is established.

    I hope you can understand that different people have different needs. We usually aren't trying to live up to "peer review" standards. We're trying to help beginners, students, and hobbyists, most of the time.
     
  10. dataman19

    Member

    Dec 26, 2009
    136
    29
    I believe you will also need to isolate the two motors by using blocking diodes (one for each motor- with the common feed coming from the power supply).
    This will prevent either one of the motors from influencing the other motor.
    ...
    It is also common safety practice when feeding two sources from one DC supply (at least in the industrial world).
    ..
    Dave
    Phoenix, AZ
     
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