DC Motor questions - (dummy version)


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    Question DC Motor questions - (dummy version)

    Hi everyone
    I recently stripped a couple of Kyocera full color photocopiers and found some motors as in the image.
    The machine is 24v and these look to my untrained eye to be brush-less DC motors and they have a nice smooth 20:1 reduction box as well.
    Can these motors run in reverse?
    If so then :
    How do I control them using simple step/dir or the servo library used by the Arduino boards to control CNC motion?
    Can the GRBL app be used to do this without major modifications/rewriting?
    I have included as much information in the image (markings etc).
    Please remember that I am an electronics idiot and be gentle.
    Thanks

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    Default Re: DC Motor questions - (dummy version)

    How many wires do the motors have?



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    Default Re: DC Motor questions - (dummy version)

    Hi andypugh
    +24v
    G24
    +5v
    GND
    S/S
    CLOCK
    LOCK
    HL

    On the image, bottom left sub-image it is the white connector on the PCB

    Did not mention that there are 2 of what looks like optical sensors running from the main board to a board on the output shaft side of the gearbox - 4 wires running to each.



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    Default Re: DC Motor questions - (dummy version)

    Images are not coming through here.
    And whilst I know quite a bit about controlling brushless motors, I have not seen that set of pins before.
    What happens with just 24V to +24 and G24?
    What happens with 1V ?
    If it moves with 24V and with 1V, then (and only then)
    with 1V and the connections reversed?



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    Default Re: DC Motor questions - (dummy version)

    for some reason the image did not attach in the original post - sorry guys

    Attached Thumbnails Attached Thumbnails DC Motor questions - (dummy version)-servo-query-jpg  


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    Default Re: DC Motor questions - (dummy version)

    I suspect these could be Reluctance motors.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


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    Default Re: DC Motor questions - (dummy version)

    Al
    What in the world is a "Reluctance" motor - never heard of that one - Google, here I come.



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    Default Re: DC Motor questions - (dummy version)

    To quote Wikipedia, "Reluctance motors can deliver very high power density at low cost".
    Low cost makes sense as far as the manufacturer goes - there is a LOT of stuff in one of those photocopiers.
    I think I am going to take one apart just to see but it has the "thimble" that I saw on an example of a brushless dc motot.
    I'll do it as soon as I can
    Thanks so far guys



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    Question Re: DC Motor questions - (dummy version)

    When in doubt, use a hammer - the bigger the doubt, the bigger the hammer.
    There are a few clips that hold stuff in place that you cannot get to once the unit is closed - hence the hammer approach.
    There is a circular coil array (seen something like that in a CD drive ???)
    3 wires coming out but have a look at the 3 diodes - surely no circuit is open there?
    There are 3 IC's, the large one had the heatsink bolted to it BEFORE it was soldered onto the board - some sort of power driver ???
    The small IC has no markings at all
    The other IC is as follows:
    HFEN | NE
    VG300SP
    8CASG
    (I think - even with a 100 mm magnifying glass it took a long time to read the markings)

    Oh well, I buggered one up....

    On the bright side I will have a VERY smooth, NO BACKLASH 20:1 GEARLESS gearbox IF I can figure out how to get the box section working without the large cup and its magnet.
    Thats right. Its a friction planetary setup - smooth as silk.

    By the way, on the output side of the box there are 2 "things" with 4 wired coming from the main board.
    Their markings :
    R40H
    82A

    Anyone know what they are about?
    Probably something to do with position detection.

    Thanks guys

    Attached Thumbnails Attached Thumbnails DC Motor questions - (dummy version)-servo-motor-stripped-jpg  


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    Default Re: DC Motor questions - (dummy version)

    What you have there is an Outrunner motor, the outer is the rotor.
    The principle is used in anything from RC motors to washing machines, Fischer-Paykel. Direct Drive Motor - Fisher & Paykel Direct Drive Motors, Pancake Motors, DD Motors | Fisher & Paykel
    Also internal rotor type is know as ECM Electronically Commutated motor used in furnace and HVAC
    The three sensors are used to detect the rotor position for electronic commutation similar to a normal BLDC motor.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


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    Default Re: DC Motor questions - (dummy version)

    Quote Originally Posted by Al_The_Man View Post
    What you have there is an Outrunner motor, the outer is the rotor.
    The principle is used in anything from RC motors to washing machines, Fischer-Paykel. Direct Drive Motor - Fisher & Paykel Direct Drive Motors, Pancake Motors, DD Motors | Fisher & Paykel
    Also internal rotor type is know as ECM Electronically Commutated motor used in furnace and HVAC
    The three sensors are used to detect the rotor position for electronic commutation similar to a normal BLDC motor.
    Al.
    Thanks Al
    Now I need to go learn about yet another type of motor - Oh well, I'm learning more since I retired than I ever knew possible.
    Or maybe I need to just figure out how to re-use the boxes.



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    Default Re: DC Motor questions - (dummy version)

    Quote Originally Posted by MadAubrey View Post
    Thanks Al
    Now I need to go learn about yet another type of motor .
    You might not need to learn much. I expect that all the power driver electronics is on the PCB, and you just need to apply 24V for it to spin. The 5V and other pins are likely to just be for feedback.

    The motor is actually extremely similar to most PC cooling fans.

    Brushless motors are not to hard to understand. They are basically a three-phase motor except that instead of the rotor chasing the input phase, the input phase runs away from the rotor :-)



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    Default Re: DC Motor questions - (dummy version)

    PC motor fans are BLDC but only two pole, they have a small IC that picks up the rotor position in order to commutate.
    The servo BLDC has exactly the same construction as a 3 phase P.M. synchronous, the difference is in the commutation, BLDC energizes 2 windings out of the three at any one time, and represents a DC brushed motor turned inside out (hence BLDC) , the 3ph uses a 3phase sinusoidal supply.
    The 3ph being a little quieter at low rpm than the BLDC, but the BLDC has a little more torque.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
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    Default Re: DC Motor questions - (dummy version)

    Thanks for your input guys - appreciated.
    Now that I have destroyed one of these motors, maybe I need to strip everything off so that I have 3 wires from the windings and nothing else and see what I can do with it.
    Some h-bridges and the appropriate C code on an Arduino may yield some interesting results.

    Everyone is probably wondering why I don't just go with steppers to drive the arm - unfortunately here where I live, the larger 23 and up steppers with decent torque are not affordable after you have added courier shipping (posting is not an option unless you add insurance which brings the price back up to courier levels).
    The other reason is that there needs to be position sensors on each joint that will drive the motor to keep the joint at its required angle no matter what.
    This is because the joint drive motors will all be in the base and each joint will be moved using a winch like setup.
    Problem is that when one joint is moved, the winch cables of all the joints above it will be shortened or lengthened thus changing the angle of the joint and that is why the position sensors need to be on the joint and not on the drive motor.
    Doing positional feedback on the motor wont help because its not the motor that is moving out of position, its the joint that will be moving and causing positional drift.
    And I still need a rather strong drive system motor (very low speed, high torque) to winch the arm sections around.

    And once I have the arm built then I can start on the "g-code to motor position" driver code which will also have to factor in the arm joint positioning signal and make appropriate corrections on the fly.
    Like GRBL but on a serious overdose of steroids.
    Out of the box it would be able to do 5 axis machining using a normal g-code input file source and a router as an end effector.
    Could possibly create a nice little revolution in the home CNC arena.

    That should not be too difficult to do, just tedious (have you seen those kinematic formulas?) as I have been programming in various languages since 1985.
    The mechanics is also relatively easy for me since I have been a qualified artisan in that field since 1979.
    Its just this damn thing called electronics that is beating me about the head
    Its funny how something as small as an electron can give a person such a big migraine....

    Just to let everyone know, we are moving soon so my attention to the forum (and most other normal duties) will be sporadic in the next month or 2 while we are getting everything settled so please keep posting and I will catch up when I can.

    All the best, stay safe and go well.



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DC Motor questions - (dummy version)

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