Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Largest Gear Ratios Possible

  1. Feb 24, 2010 #1
    Hi, I'm new to the site so I hope I'm in the right place, I have a question regarding gears for a project that I am working on at uni.

    I'm designing a building which has a steam driven turbine at the base, what I want to have is levels above which are attached to the same axle as the turbine but spin a lot slower. The obvious way to run this is to involve a gear system for which I made a model below. This used a simple gear that I took out of a cheap clock. So the model works on a 1:12 Ratio

    However, A Steam Turbine can turn at approx 5000RPM, I would like the levels above to turn at a rate of approx 1 rotation and hour, which is about 0.02RPM I think?

    Is anything like this possible, its obliviously a massive step down. The building has a 20m diameter so a lot of space is available if massive gears are required. But where do I start with working out how it would work, would a planetary gear system support it?

    Any help or advice on this would be greatly appreciated!



    Attached Files:

  2. jcsd
  3. Feb 24, 2010 #2


    User Avatar
    Science Advisor

  4. Feb 24, 2010 #3
    Thanks, found some good info on Radio telescopes. I'm intrigued by the Hotel rotating floors though, have you got any links to anything on those, not sure if i'm searching for the right thing
  5. Feb 25, 2010 #4
    Worm gears provide some large ratios. This guy set up a worm-gears in series....the input is 50 rpm, and the output is so small, that he encased it in concrete because it really doesn't matter.

    It would make a complete revolution in about two trillion years...

  6. Feb 25, 2010 #5
    it will depend on the torque required at higher level....cause module is dependant on that....also the shaft diameter will also come into picture...with its cost....i m not getting weather ur asking for a model or for a protocol???
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook