Motor Configuration Puzzle

Discussion in 'General Electronics Chat' started by onejames, Aug 13, 2010.

  1. onejames

    Thread Starter New Member

    Jun 12, 2010
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    I have a puzzle, for anyone willing to help!

    I came across several of these DC motors, pulled from a Dell 3100CN Laser Printer. Unfortunately i cannot find any documentation on how these are configured. I have tried googling every combination on the part numbers listed on the outside casing, with no luck. Finally i ripped apart one of them to find a manufacture stamped on the PCB, a little research later i came across this PDF: http://www.nidec.com/admcmc/22h.pdf . This does appear to be the motor in question, but i am unable to figure out which of the 6 leads out of the motor correspond to the 8 available options on this motor. I would assume that the Red/Black leads are +/-, and that the motor runs at 24V (based upon the other components in this printer).

    I have tried to connect a PWM and +5v (start stop control) from an Arduino to every other available pin, and cannot get it to turn…

    Here are pictures of the motor:

    http://farm5.static.flickr.com/4096/4885202859_74c6b6aa8d_b.jpg
    http://farm5.static.flickr.com/4123/4885805850_e1821d777d_b.jpg
    http://farm5.static.flickr.com/4074/4885202759_be5c880cd4_b.jpg

    Thanks for any help you can offer!

    - James.
     
  2. marshallf3

    Well-Known Member

    Jul 26, 2010
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    its a stepper motor, trace the leads back to the IC that drives it and look that up, should give you some insight.
     
  3. onejames

    Thread Starter New Member

    Jun 12, 2010
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    It is not a stepper motor, it is a 3 phase dc motor. I have verified this by taking it apart. And the documentation I have found, confirms this.
     
  4. marshallf3

    Well-Known Member

    Jul 26, 2010
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    My apologies, most are and I just assumed. Regardless, looking at what drives it is going to help.
     
  5. onejames

    Thread Starter New Member

    Jun 12, 2010
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    I appreciate your reply! I have traced it to the best of my ability, but it has not led to any insights... Any suggestions on another way to figure this out?
     
  6. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    These are normally called "brush less DC motors" or "BLDC motors". If you do a web search you will get a lot of information on them.
     
  7. onejames

    Thread Starter New Member

    Jun 12, 2010
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    Maybe I need to clarify things a little better. I know that this is a 3 phase 12 pole 24V DC brushless motor. I also know how to drive and control a DV brushless motor. The problem is that there are 6 wires that are attached to this particular motor, and according to the documentation that I have read about the Nidec 22H series motors, they can come with up to 6 options (8 wires total). They are: PWM, Start/Stop, CW/CCW control, Locked Rotator Alarm, Tach1, and Tach2. It also has Vm, and GND, but they are not optional, and I would assume they are the red/black wires.

    The problem I am having is figuring out which wire does what function.

    Thanks for any help in advance.
    [​IMG]
     
  8. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Looks fairly self-explanatory to me except what it's expecting to see on the PWM input, probably also just logic level and the duty cycle controls the speed.
     
  9. onejames

    Thread Starter New Member

    Jun 12, 2010
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    how can it be self-explanatory with 6 wires, and 8 options?
     
  10. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Because most of those pins wouldn't be used or would just be tied to power or ground.

    To simply "run" the motor it only needs power, ground and a PWM driving signal.
     
  11. onejames

    Thread Starter New Member

    Jun 12, 2010
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    but what wires are what? I have put GND/ +24v to red black, and 5V (assuming there is a start/stop control) & PWM systamaticly to all other pins, and nothing happens...
     
  12. GetDeviceInfo

    Senior Member

    Jun 7, 2009
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    First thing I'd do is check up on that BD6921 brushless motor controller and I wouldn't be surprised if those same functions where pulled directly, or indirectly from that device.
     
  13. onejames

    Thread Starter New Member

    Jun 12, 2010
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    Well i wrote Nidec about the motor, and got this responce:

    "Basic documentation of 22H motors is posted at http://www.nidec.com/admcmc/admcmc.htm, but a description of features and unctions of application-specific design variations, including pin-outs, lead wire identities, and logic level options, is protected as customer-proprietary information and is not publicly documented by Nidec."

    Helpfull huh?
     
  14. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Can't you use a Ohm meter to check out the pin-out?

    Three of them would be common to a fourth one. This would be the 3 stator coils and ground. From those 4 you could measure the Ohms between them to figure the ground from the coils. Two coils would be around twice as much as a coil and ground.

    After that you would use ground to figure which one is the Hall effect sensors. I would think that they would have continuity but the tach out puts wouldn't.

    Or to figure the Hall effect from the tachs you could wire the coils and ground (found in first step) to the driver. Power it up with a PWM signal on it, and one by one connect remaining wires to the Hall effect pin on chip. When you get the right wire the motor will start to turn.

    This may not be the only way to figure it out, but it's the way I would trouble shoot it.

    Another way is if you still have the printer look and see if you can figure out the traces on the circuit board, from the motor wiring connector back to the driver chip. The coil traces should(maybe) be wider than the Hall effect and tach traces. The ground should be tied in some way to other grounds on the board. Make sense?
     
  15. onejames

    Thread Starter New Member

    Jun 12, 2010
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    Thanks!

    Makes sense, and that is what i initially tried to do, but it looks like everything runs through the microcontroller, so i do not really get any kind of usable readings.

    I am going to try and reverse engineer the printer next, see if i can get any clues from the whole thing...

    I have enough of these motors that if someone can convince me they can figure these out, i would be willing to mail one... or two, no return expected, if you can get them to work.
     
  16. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    The first part of the method I was suggesting, figuring out the coil wires, has to be done with the motor disconnected from the circuit board. Various parts inside the chip could give a false reading if you don't disconnect the wires.

    Or are you saying that the motor has the chip built into it?
     
  17. onejames

    Thread Starter New Member

    Jun 12, 2010
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    This is the board that is inside the motor:

    [​IMG]

    [​IMG]
     
  18. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    here is a similar data sheet; http://pdf1.alldatasheet.com/datasheet-pdf/view/186884/ROHM/BD6922FV.html It's for the BD6922 but I would be willing to bet that the pin out for the chip is the same.

    From this you can figure out the wiring on the board to the outside world. I'll bet you only need to connect three wires to get it to run -
    1. A positive voltage in
    2. A negative out
    3. A positive logic voltage to turn it on

    The board looks like it has a crystal on it, that probably takes care of the PWM.

    I thought it had a separate drive chip from the printer board instead of built into the motor.
     
  19. onejames

    Thread Starter New Member

    Jun 12, 2010
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    True, unless there is also a start/stop control in there, and because it came from a printer, i would expect it would, along with a locked rotor alarm. but still that is just a +5 to a random pin.
    I came across these too:
    http://pdf1.alldatasheet.com/datasheet-pdf/view/6589/NEC/UPA1792G.html
    which are close enough to the 3 other chips, N- and P-Channel MOSFET.
    I will do some paint-scraping and see where some of these traces lead...
     
  20. osamazhar

    New Member

    Feb 21, 2010
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    Its so long since the last post in this topic, but still I hope somebody will reply to this. I too got this motor a couple of months back, and today when I thought to run it and searched on the net for the configuration I came to this thread.

    if anybody especially brother onejames can tell me how he ended up with this motor and the pin configurations etc.

    I would be very lucky to get the reply here :)
     
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