12 V DC Motors

Discussion in 'General Electronics Chat' started by Dyers, Dec 17, 2013.

  1. Dyers

    Thread Starter New Member

    Dec 11, 2013
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    I've built an electric spinning wheel, an e-spinner for short. Currently, I'm using a Mabuchi #RS-555PH from Allelecrtronics.com with this controller. It's remarkable what these little motors can do, and their prices make them seem even more remarkable.

    I've gotten all the little bangs, creeks, and whines worked out of the e-spinner's mechanical parts. When I started that process, the motor was inaudible. It's noise level is certainly acceptable, but I'd like to find something considerably quieter because it is pretty audible, now. I don't experience any shortage of torque, though I don't want to sacrifice any. I would like to increase speed.

    In short, I'm looking for something quieter, just as torqued, and as much faster than the Mabuchi I am using at the moment as is practical. I telephoned All Electronics...who referred me to one of their retail stores for questions concerning their motors. I did, and was passed to their motor expert. He advised me to try the Igarashi Motor # 3657-070-GF-5. Neither are well described in the catalog, and spec sheets are also somewhat elusive. The guy at All Electronics said the RPM was near double in the Igarashi, but that torque, and audibility were about the same. I'd like to be able to confirm that, if possible.

    Do you know of something that might do what I'm looking for? Long life is of higher value than purchase price, and may even trump quiet. I'd like to hear your suggestions and thoughts about any aspect of these motors.
     
  2. GetDeviceInfo

    Senior Member

    Jun 7, 2009
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    You'd seriously consider brushless if longevity is important
     
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  3. Dyers

    Thread Starter New Member

    Dec 11, 2013
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    Thanks; I meant to ask about brushless vs. brushed, but my message was getting long so decided to skip it until a bit later. Brushless it is.
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I guess you realize you will need a different controller, AC or BLDC controllers are not so common, You can get small BLDC drives with ±10vdc analogue control fairly reasonable on ebay, Advanced Motion etc.
    Max.
     
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  5. Dyers

    Thread Starter New Member

    Dec 11, 2013
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    I am just beginning to realize that. I searched eBay for ±10 vdc analogue; Google as well. Often, when learning about something that's new to me, I can glean information by reading product reviews, watching video tutorials, or read blog and forum posts, but I'm not finding anything yet to start to break down the data into manageable sized chunks. I'd like to be able even to find a motor & controller that are priced at a level that I can experiment with.

    The cost of the brushless motors & controllers may keep me in the brushed marketplace, at least for a while longer. There is an additional commitment to the controller I'm using; the beautiful hardwood that makes up the frame of the e-spinner has been locally dimensioned in 3 places to accommodate the power connection, power switch, and potentiometer.
     
  6. inwo

    Well-Known Member

    Nov 7, 2013
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    Often noise is affected by mounting methods and coupling methods.
    A picture would be nice.
     
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  7. Dyers

    Thread Starter New Member

    Dec 11, 2013
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    Right; this machine is intended to allow a spinner to produce yarn in production speeds & quantities for people working in a fibers based cottage industry, for example.

    [​IMG]

    I think new motors over used ones would be best if I am to learn how much life I can expect from a given motor. I'm also considering the possibility of marketing these on a limited basis, so I'd need at least to have a ready source for new ones if I go that route.

    The Mabuchi I'm using has a (no-load) speed of 4,600 RPM. I don't know how to measure / calculate RPMs under load. I don't ever feel or hear it straining; it runs at a steady rate whether the bobbin is empty, or contains as much as 1.2 kg of yarn. This one isn't a geared motor.

    Speed is important to a production spinner, though. Each rotation of the mechanical part of the spinner produces one twist in the new yarn. If the top speed is, say, 350 RPMs, which is probably in the ball park, and if the spinner is aiming for 8 twists per inch, then s/he can produce approx. 4 feet of yarn per minute, or about 240 feet per hour...not very fast, but probably in the neighborhood of spinning the yarn using the pedaling action of traditional spinning wheels. If I look for a motor which is too fast for a spinner to use, s/he has room to improve skills.

    Sound is also important. Traditional spinning wheels make a soothing, rhythmical series of quiet noises as the various wooden parts move, interact, and move air. There are some of those sounds in this e-spinner, but now that those I can find have been dampened, or eliminated, the prevalent sound is a pervasive buzz. It's not so loud that one has to speak loudly over it, it's just not especially pleasant.

    The motor is mounted inside a wooden box which essentially doubles as a resonator. I used 4 screw eyes to lift the motor off the wooden case, a small piece of thin mouse pad to dampen vibration, and a cable tie through opposite pairs of screw eyes to secure the motor. If I apply pressure to the motor's housing with my finger while it is operating, I can detect no change in the sound.

    [​IMG]

    The motor is coupled to the machine using a 1/8" clear, slightly elastic material that's frequently used as the drive belt for spinning wheels, both foot powered, and electric.

    [​IMG]

    Sold by the foot, it's elasticity is appreciated for both ease of sizing and use. The cut ends of an intended belt are heated by holding near a flame, then holding the softened ends together for 30 seconds until the poly material cools. This joint, even when carefully trimmed, is associated with an almost inaudible plucking sound twice each rotation, each time it contacts one or the other pulley. The more of these plucking sounds you pack into a short period of time, the more like a vibration it sounds, I'm sure, but this isn't similar to the buzzing sound that the motor makes. The pitch of the motor increases as RPMs increase .

    Some questions:

    • How many hours of use might be expected from a brushed DC motor such as the Mabuchi, and Igarashi mentioned in the OP?
    • How closely related are speed & torque, that is, as one increases, will the other necessarily decrease?
    • Might a belt that's too tight, or too loose result in the sort of sound I'm hearing?
    • Comparatively, does the price I pay for a motor have any bearing on the desired traits of
      • quiet
      • increased speed
      • either uncompromised, or increased torque?
    • Are there higher-end brushed motors than these I've been finding?

    Here are some more images.

    Thanks very much for having taken the time to look, and for your responses. I appreciate it.
     
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  8. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Based on your investment in time and materials, you might want to invest in a brushless motor and controller. Surprisingly, the very small motors available to the RC airplane market provide incredible torque and rpm and nearly silent. Motor controllers for RC are widely available over 20 amps.

    All parts are available for these motors, shafts, bearings are mos common. Check out Hobby Express in cranberry township, PA. They have a huge stock of motors and replacement parts. Otherwise you can check eBay/craigslist for used and rebuild one.
     
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  9. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    I built a shuttle bobbin winder for a loom, not the same but a similar thing. Copied it from a one sold in the weaving shop. The one I copied and built used a sewing machine motor and foot pedal to control it.
     
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  10. MaxHeadRoom

    Expert

    Jul 18, 2013
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    It is very hard to obtain silent operation of a motor/mechanism running at 4600rpm.
    Traditional spinning wheels run at a relatively low rpm.
    DC motors have ran many years in a production environment, regular preventative maintenance is important, check brushes etc.
    The torque curve of a DC motor is relatively flat from maximum at zero rpm to a relatively flat curve up to max. rated rpm.
    AC servo type motors are just about the most silent in operation, but are the most costly.
    Higher end DC brushed motors are the servo rated variety.
    But running at the rpm of 4500+, any noise is most likely to be from the belt drive and/or gearing mechanism etc.
    The motor itself is the most silent.
    Max.
     
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  11. Dyers

    Thread Starter New Member

    Dec 11, 2013
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    Hey, neighbor; thanks for that advice. Cranberry is only about 45 minutes from me, and having someone that close to look at what I'm doing, then provide some advice, and direction face to face will be extremely helpful. With the information you gave me, I can see the broad range in which they are available. Narrowing it down might have been trickier without that kind of advice.

    Ha! I actually started with that arrangement. It is quiet, very fast, and they are easy to find in a price range I can swing. I didn't use the newer style electronic / solid state pedal, and the carbon rheostat in the pedal I had available gets very hot. I'm not too keen on all the external wiring with these, though. They are also (usually) brushed.

    This goes to the heart of some of my questions. The 4600 RPM is a bit deceptive, though, in that, under load, it comes no where close to that. I doubt very much that it even reaches 10% of that speed when under load. Maybe you know; how does one measure actual rotation speed when the speed is faster than I can count?

    I've known of servo motors for a long time, but I don't know what differentiates them from other motors. Some of those I've seen rival the price of a well designed and manufactured e-spinner.

    My limited experience supports that. I've used another of these motors to operate something that originally operated manually. The load must be greater, though, because after 30 - 45 seconds, it slows down, then stops. As the chips cool, it functions again. I've twice replaced the heat sinks with others that have more surface area, and that's helped, but it is far short of a solution. I have that one mounted inside a deep, single utility switch box, and even it gets hot. I will replace this controller as soon as one of the newer type controllers arrive. The one that's getting so hot is based on an Arduino programmed microchip. It is the same model number (motor), but does not make the buzzing sound. I've got some more digging to do.

    Funnily enough, I just replaced the brushes in my 1/4 hp bench top drill press. The pair cost $4.99, free shipping. At $3.50 a motor, maybe I should just consider them expendable, and replace them when their brushes wear down. I don't see how to access them to replace them.
     
  12. Dyers

    Thread Starter New Member

    Dec 11, 2013
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    I wonder how I missed mentioning this. A spinner needs to rotate both CW, and CCW. Most yarn starts with a twist that goes in one direction. Some fibers workers require the opposite direction for various reasons, too. Whichever way it's originally twisted as it's being spun, the plies are twisted together in the opposite rotation. This is important to counter the "active twist" of the spin, rather than the opposite. Yarn with too much twist is difficult to use because it wants to double back on itself, and twist.

    Are controllers easily obtainable to reverse rotational direction? Also, installing the switches in a way that looks clean, and well crafted is highly important. On the front, near the tensioning pin, is a for/off/rev power switch, and a potentiometer; both have wire leads that are connected to terminals on the PCB. Are these same devices usable on brushless controllers?
     
  13. inwo

    Well-Known Member

    Nov 7, 2013
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    Is that a large solid mounted ball bearing in the picture?
     
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  14. Dyers

    Thread Starter New Member

    Dec 11, 2013
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    There are 7/8" ID bearings mounted in the wooden structure of the spinner, near the top of the catenary arch ends. They support the central aluminum shaft to which the pulley, and flyer arms are firmly fixed. If the pulley rotates, all of those parts rotate with it at the same rate. The bobbin spins independently around that shaft.

    I take it by your having asked about those bearings that they potentially pose an issue?

    ETA; Until about a week ago, I was using a 1.2 A sewing machine motor, and carbon rheostat foot pedal. It didn't make the buzzing sound. Sewing machine motors, I read, are either not possible to reverse, or cost prohibitive. To reverse rotation of the spinning apparatus, I made a figure 8 of the drive band. Drive bands don't like friction, though, so that idea has been abandoned. I bring it up here because of it's potential use in debugging any potential problem with the bearings.
     
    Last edited: Dec 18, 2013
  15. inwo

    Well-Known Member

    Nov 7, 2013
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    Yes, just a thought.

    A long ago project for an advertizing scroll sign had noise issues that we never solved.

    So I'm no expert. It didn't help that I'm near deaf.:(

    Here is the remains of another long lost project. Winding ticker tape.
    God, I'm old!

    Had similar demands.
    Quiet and constant torque.

    I'll research it, but these types of motors are from an art long lost to electronics.
     
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  16. inwo

    Well-Known Member

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  17. MaxHeadRoom

    Expert

    Jul 18, 2013
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    There is a popular tach same as ebay 380643100141 for $10-$15.
    Servo's are made with higher pole count, and skewed rotor, and made a bit more durable.


    Drives either come with fwd/rev or usually are easily configurable, but may require a couple of relays in some cases, depending on what kind of drive you get.
    Max.
     
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  18. Dyers

    Thread Starter New Member

    Dec 11, 2013
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    Thoughts count; they're the seeds of all great ideas except cell phones.

    Yeah? Did you play with used key-punch cards as a kid? :D

    Thank you very much. I'm so interested to see what you learn

    Thank you again. I can see these are going to take a couple of times through to absorb it; it's really interesting stuff after just a quick scan.

    Excellent, and very useful information; thanks for having gone to that trouble.

    Thanks again for these useful data. It was your suggestion that, "any noise is most likely to be from the belt drive and/or gearing mechanism etc.
    The motor itself is the most silent." that got me to look more critically at all aspects of the drive train. I found a very small, but perceptible (0.5mm?) lateral movement of the motor shaft. It created a small tick-like sound every time a rotation was made, even during intentionally slow manual rotations. I moved the pulley as close to the motor housing as the motor shaft allowed, backed it out a tiny fraction of a mm, then tightened it.The buzzing is gone. If you look closely at this image,

    [​IMG]

    you might see a very slight kink or offset in the drive belt at the 4 points it enters & exits both pulleys. It gave me reason to look where I did with the drive pulley on the motor shaft. Your suggestion pointed me in the correct direction.

    So, now I just need to decide whether to stay married to this brushed technology, or flirt a bit longer with the brushless options available.
     
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  19. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Your belt drive appears to be driving at an angle to the pulley rather than truly perpendicular to each shaft?
    This will can cause issues with wear and noise.
    It is much better to keep the belt perpendicular, regardless of what sheave it is on.
    A note on the Tachometers, if you get the same one, they are available from many sources, I suggest you remove the battery when not in use, as there appears to be a current drain when off, I, and others found this out the hard way!
    Max.
     
  20. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    A sewing machine motor can also be powered by DC, they are a "universal" motor. That would make it reversible. By using a DPDT switch or relay.
     
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