Power Supplies

Discussion in 'General Electronics Chat' started by rockboy, Dec 7, 2008.

  1. rockboy

    Thread Starter New Member

    Dec 7, 2008
    4
    0
    Hi

    I recently built a stepper motor controller based on Easy to build CNC Mill Stepper Motor and Driver circuits

    It originally worked fine with the testing motor i used (Jaycar Electronics)

    But then when i put my new motor on it

    (motorspec.pdf)

    It doesn't work, i have a 12v 2.5 amp supply on this circut and according to the specs they are both 12v 400mA motors, but I'm pretty the problem is that the new motor is drawing to much current maybe.

    I have an old pc supply with a 12v+ 15A output, if i use this supply will it work?

    Also i have heard a little bit about a constant current source may be required but i cannot for the life of me understand the differance between a constant current source and a voltage regulator since they both seem to use the LM317 ic, i have googled this to death and had no luck.

    Many thanks in advanced

    Glen
     
    Last edited: Dec 8, 2008
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    The motor is rated 3.6V and 1.2 Amps. If you connect it to a 12V power supply it will much current and trips the power supply's current limit sensor (if it has) otherwise the motor is gone! You old power supply won't work because you need a 3.6 power supply.
     
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    It might be ok to use the SMPS's 3.3 volt output.
     
  4. machinejack

    New Member

    Jul 28, 2008
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    Is the new motor wired unipolar or bipolar?
     
  5. mik3

    Senior Member

    Feb 4, 2008
    4,846
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    I have never worked with stepper motors but I think is bipolar because it only four wires, two for each winding. If it was a unipolar it would have five wires. Maybe someone more experienced with steppers has the exact answer.
     
  6. machinejack

    New Member

    Jul 28, 2008
    3
    0
    The driver in the above post is a unipolar. The motor having only 4 wires I would say it is a bipolar and it will not work with that driver. Find a 8 lead you can hook it up either way. If you are in to building boards I have had real good luck with Phil Moore at pminmo.com. He is very very helpfull. Lots of good stuff on his site. That is were I got started. He sells a real good bipolar driver based on the A3977 chip that has worked great for me. As for voltage I am in the process of hooking up 2 bipolar 3.5 V and the voltage for them will be 51V. Using a chopper driver the voltage potential will not reach peak also at higher voltages you will have better high end speed and power.
     
  7. rockboy

    Thread Starter New Member

    Dec 7, 2008
    4
    0
    Thanks for all the help guys, unfortunately I posted the wrong motor before, the motor is unipolar and the specs can be seen here .

    So should the 12v supply work given that both motors are 12v, or will i destroy the new motor?

    Cheers
     
    Last edited: Dec 8, 2008
  8. rockboy

    Thread Starter New Member

    Dec 7, 2008
    4
    0
    I thinking i might just try the computer 12v supply and see what happens, unless someone thinks this will detroy my motor.

    Many thanks
     
  9. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    The two motors appear to have identical voltage @ current specifications; only the step angle is different.
    If one works and the other doesn't, double check your wiring. +V should be to the white and black wires.

    Your link to the stepper driver board instructables is not working.
     
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