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1332Re: [rsa] commutator questions

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  • Terry Slocum
    Sep 2 8:06 AM
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      Douglas,

      It depends a lot on what type of signal you are trying to put through it. To control the motors on a crane model I made, I used a piece of copper clad circuit board material and etched some rings in it. I used spring loaded brass brushes. It seemed to work fine.

      If you are trying to pass video, or worse yet modulated video you will have a huge signal loss as soon as the signal leaves the sheilded environment of the cable. Whatever material you use for the "commutator",it will act as an antenna and radiate most of the signal into space. You might try putting a small transmitter in the camera head. Or use something to modulate the video feed onto a low frequence (60hZ) carrier. Some of the low end TV distribution systems work this way. There is also a system for model railroading that lets you put a video camera on the train and transmit video through the wheels to the track.

      Terry

      --- In sfrsa@yahoogroups.com, douglas irving repetto <douglas@m...> wrote:
      >
      > david said:
      > >Most guys build their own...
      >
      > That's what my friend has been doing (machining his own), but he's
      > having real trouble with wear and noise in his signals. These are art
      > installations that are on for very long periods of time. He has been
      > experimenting with various materials and designs, but can't come up
      > with anything that's consistently quiet and durable. Any advice or
      > pointers to info?
      >
      > thanks,
      > douglas
      >
      >
      >
      >
      >
      > >At 17:34 30-08-03 -0400, you wrote:
      > >
      > >
      > >>hi,
      > >>
      > >>
      > >>a friend of mine is working on a bunch of projects that involve
      > >>rotating cameras. he's been having trouble finding a reliable
      > >>commutator design. can anyone point me to some online or book-based
      > >>info on commutator design?
      > >>
      > >>(by "commutator" i mean a device that allows you to feed
      > >>power/signals to a rotating part, as opposed to a device that turns a
      > >>motor's output from AC to DC. is "commutator" the correct word for
      > >>this?)
      > >>
      > >>thanks,
      > > >douglas
      > >>
      > > >
      >
      > --
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