1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How fast would an electric motor spin in space?

  1. Aug 15, 2011 #1
    If you had an electric motor in space how fast would it spin since there is no friction? Would it build up to light speed?
  2. jcsd
  3. Aug 15, 2011 #2


    User Avatar

    There are lots of electric motors in space (all those satellites and their mechanisms...) and they behave exactly the same as on Earth.
  4. Aug 15, 2011 #3


    User Avatar

    Staff: Mentor

    Being in a vacuum and 0g does very little to reduce the friction inside a motor.
  5. Aug 15, 2011 #4
    Wouldn't it overheat easily without any atmosphere to transfer internal heat?
  6. Aug 15, 2011 #5


    User Avatar
    Staff Emeritus
    Science Advisor

    Yes it would.
  7. Aug 16, 2011 #6
    So the only way for the object to cool would be to expand. You would expect that any mechanical unit in space would explode eventually with no way to remove the heat.
  8. Aug 16, 2011 #7


    User Avatar
    Gold Member

    1] There's no conduction and no convection, true, but there's still radiation, which is the method by which objects in vacuum transfer heat. But radiative cooling is comparatively slow.

    2] While parts of the object will expand with heat, it will not go on indefinitely, and will not almost certainly not result in explosion. At some point, the heat will cause a part to fail - it might simply be a CB component burns out. The device stops working and stops producing heat.
  9. Aug 16, 2011 #8
    That is much more logical. Thanks.
  10. Aug 16, 2011 #9
    My understanding of heat is limited to my oven and summer time.

    Pretty cool to consider what heat is.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook