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!

Gear reduction

  1. Jun 12, 2014 #1
    I have a 3hp motor, with a torque of 110.85 lb*in. a gear box with a max torque of 6286 lb*in.

    gear box ratio is 57.64:1

    I have gears attached to the gearbox shaft with a gear reduction of 3.375:1.

    My new gear ratio should be 194.53:1 right?....

    which would make my output torque approx. 21,500 lb*in...?

    just checking
  2. jcsd
  3. Jun 12, 2014 #2
    Are you sure about your motor's torque? I ask because you list the gearbox's max torque (is that it's rated torque) at a value that is lower than the motor torque*reduction.

    Also, understand that AC motors (if that's what you are using) are not constant torque machines. They have torque curves, and starting/peak torque can be upwards of 200% (in some cases much higher) of rated torque.

    I'd verify you've got the right parts for the application.

    As per your question, yes, if you have a gearbox with a 57.64:1 ratio and the output of that is subjected to another 3.375:1 reduction, you will have a 194.53:1 reduction and theoretical torque of 21,500 in*lb (depending on efficiency of the powertrain).
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook