Wiring Problem

Discussion in 'General Science & Technology' started by domesticated om, Mar 31, 2006.

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  1. domesticated om Interplanetary homesteader Valued Senior Member

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    Q: Can someone give me a few common techniques people use to run electrical wiring through a rotating object (like a propellar)?
    Let me give you an example of what I'm talking about....

    Lets say you have a ceiling fan, and you want to mount light bulb sockets on the tips of the fan blades. How do you wire the sockets while keeping the wires from winding/spooling around the fan? Is there a common electrical doohicky people use to do these kinds of projects?
     
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  3. Blue_UK Drifting Mind Valued Senior Member

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    Just guessing, but you could have concentric circular tracks. E.g. like a record player with two needles and two separate copper tracks on the same disk.

    A variation on this technique is used on the standard 3.5mm (or 6mm) phono jack, which has separate circular tracks on a cylinder. You can twist the walkman about as much as you like on the phono plug without disconnection.
     
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  5. vslayer Registered Senior Member

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    im not sure ify this is what they use, but i would suggest:

    have 2 copper rings around the motor/attachment to ceiling, separated by an insulator, make grooves in the rings, in which you would put some conductive ball bearings, then do the same on the other side, so that their is constant contact by the ball bearings between the 2 surfaces. from those rings you can run as many wires as you want without them tangling.

    EDIT: looks like blue beat me to it
     
    Last edited: Mar 31, 2006
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  7. leopold Valued Senior Member

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    yes there is but its used inside motors
    there are 2 types
    the slip ring type described by blue_uk
    and the commutator type
    the commutator type is that segmented copper cylinder inside motors

    the slip ring is used for ac while the commutator is used for dc

    i know of no commercial product designed for your needs
     
  8. superluminal . Registered Senior Member

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    Google on slip ring commutators. You'll find zillions of manufacturers and type.
     
  9. cato less hate, more science Registered Senior Member

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    I don't think it is a good idea to put light bulbs on the end of a fan. what if someone stretches their arms up and gets, not only a light bulb broken on them, but electrocuted in the process.

    since I am 6'10, I would not want to come anywhere near something like that.

    finally, I would recommend you don't do it. what if your homemade commutator sparks and starts your house on fire?

    my recommendation would be to use some LEDs and strap batteries to the top of the blades. anything much brighter than an LED is probably unsafe.
     
  10. Bob the Unbeliever cogito ergo sum Registered Senior Member

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    If you go with a low voltage bulb, like one of those new "ultra-bright" white LEDs, you could go with an induction system.

    My Dremel tool has a pretty cool headlight: it uses a tiny permanent magnet under it's collet, which induces a small current for the LED 'lights.

    You could do something similar: permanent magnets around the perimeter of your fixed mount. Induction coil close, but not touching the ring of magnets.

    The rotation of the fan should generate sufficient current to more than light up the ultra-efficient LED's

    For an example of this type of device, take ANY gasoline power mower, with a vertical shaft (not a "reel" type). Looking at the edge of the engine's flywheel you will notice one or more permanent magnets in it's rim. And, you will see either a "C" coil or an "E" coil. (as in "C" shaped iron laminates or "E" shaped. Adding the missing side would be either an "O" or an "8" shape.) The "missing" side is not quite touching the spinning flywheel, and the magnets generate a current pulse which fires the spark plug.

    You may be able to use a coil from an old mower, and I know you can get very strong magnets out of old, dead PC hard drives. But, you may wish to purchase a series of all the same.

    I would suggest, since you'd be using segmented magnets, that you mount them on a disc, "horizontally" rather than vertically. Then put your coil near the disk, pointing either down or up. You'd likely want 2 coils, so you can balance the spinning weight: put each 180 degrees from the other.

    You'd need to design a circuit to regulate the output of the coils, so you don't over-supply your LED's. The Internet is chock full of examples of these (regulated LED power supplies).
     
  11. superluminal . Registered Senior Member

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    Last edited: Apr 1, 2006
  12. domesticated om Interplanetary homesteader Valued Senior Member

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    The light bulb socket idea was meant as an example, and was not neccesarily the project itself. I was just trying to think of something simple that involved electrically wiring a device that was mounted on the end of a rotating object.
     
  13. vslayer Registered Senior Member

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    if you are thinking of light bulbs, then you could always just run a live wire around the fans path on the roof, and put fluorescent bulbs underneath it. i use my plasma ball to light streetlight tubes

    Please Register or Log in to view the hidden image!

     
  14. Bob the Unbeliever cogito ergo sum Registered Senior Member

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    Here is a simple solution and example.

    Go to your favorite auto junk yard (bring tools, including a battery saws-all).

    Pick any car in the lot - preferably one with an air bag that was removed by the recyclers. (Caution! An un-discharged air bag can be DANGEROUS).

    You want an air-bag one, because there are more contacts.

    Anyway, cut the steering column thru just behind the ignition switch. Take the wheel and part-column back to your workshop: inside you will find a lovely sliding contact system just as you described.

    The more "junk" on the steering wheel, the more "tracks" will be on the contact disc. If you just want a 2-circuit one, look for an older car with just a horn.

    ...

    This method will not work with certain late-model cars, though. I forget which maker, but one of them switched from sliding contacts to a "nautilus" type of spiral. The engineers observed that the wheel has a limited rotation sequence. It cannot rotate continuously, but must stop at either end. Thus they have a spiral of wires in a slippery housing. As one turns right, the spiral contracts. Turns left, it unwinds. There is no sliding electrical contacts. GM I think, or else Ford ...
     
  15. leopold Valued Senior Member

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    an even simpler solution would be to find a automobile alternator and use its slip rings
    for a more exotic effect he can use an automobile starter commutator for flashing/switching effects
    in both the alternator and starter scenarios you must limit yourself to approx 15 volts and approx 60 amps

    superluminal
    although the search phrase worked there is no such thing as a "slip ring commutator"
    "slip ring" and "commutator" are two different devices
     
  16. cato less hate, more science Registered Senior Member

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    you are right leo, its just easier for people to know what you are talking about. how else do you describe a slip ring? putting the word commutator after it makes everyone (if they know what a commutator is) know what you are talking about. I always refer to them as a slip ring commutator, and a split ring commutator. it may not be technically correct, but it works =]
     
  17. CANGAS Registered Senior Member

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    It seems like I'm always the harbinger of doom. Sorry about that: car electric devices designed for 12v DC are going to have serious trouble coping with 110v AC. There will be arcing and pitting on the contacts. And do I need to remind anyone that 12v DC is much safer than the easily lethal 110v AC?
     
  18. MetaKron Registered Senior Member

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    It might be easier to shop for a model with the lights already installed.
     
  19. CANGAS Registered Senior Member

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    A pre-lighted item is a sterling choice.

    In the event of a diehard do-it-yourselfer, I myself would consider obtaining a small transformer, which should be very easy to find, to turn 110vAC into 12vDC. Then perhaps adapt a distribution device. But bear in mind that electrocution is not the only potential danger: electrical fires can be started by ANY voltage.
     
  20. cato less hate, more science Registered Senior Member

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    yes, maybe you should just get some tritium glow sticks, they last for years (half life of about 12 years). sadly, if you live in the US you can't buy them, illegal. you can get them in Europe though.
     
  21. bluej_x Registered Member

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    not certain why anyone would need to have lights on their fan blades. is it just to see pretty lights go round?

    you could use simple LED's and hearing-aid bateries with a simple circuit epoxied to the blades with a centrifugal switch as used on some pastic Yo-yo's. Othersise the dangerous slip ring idea is best imho. but first buy life insurance for your wife to spend with your replacement.
     
  22. cato less hate, more science Registered Senior Member

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    I would say that the induction idea is best non-battery idea (batteries still the best). electrical contacts are way more dangerous, if you induce a small current, you could run some LEDs.
     
  23. Bob the Unbeliever cogito ergo sum Registered Senior Member

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    Not True!

    Go HERE for USA Glowrings:
    http://www.outdoorgb.com/p/nite_glowring_safety_marker/
     
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