Atwood Speed help

[Matt Adams]

Originally Posted by psychoCHIPMUNKK

I’m planning on using an Atwood in an Inventor model that I’m doing for my engineering class and I came across a question; The spec sheets have "Normal load" in the performance chart, but what is normal load? is it weight specifically for this motor, or is there a standard load, say 150 lbs the motors are tested on? Any help would be greatly appreciated. If it matters, I’m trying to figure out the RPMs under different loads to calculate how fast it can move.

Basically, you have two data points... free speed and stall torque. Draw a line between them on a torque vs. speed axis. At the free speed, there's no torque applied to the motor shaft, and at the stall torque, there's no movement by the motor shaft.

For any given load (torque) you can find the speed that the motot will spin at.

There are multiple posts out there that have a lot of data on this sort of thing. I busted onto Chief Delphi pretending to know a lot about this about 3 months ago... it took a few friendly heart to hearts with Joe Johnson to set me straight. Feel free to post your application and I'll run through the math for everybody.

Atwood and Drill Data in English Units, geared at free speed of drill motor.

Here are a couple of graphs that show legitimate motor data for both the drill and atwood motors geared down to the speed of the speed of the drill motor.

Look at the post, I honestly no longer agree with some of the technical arguements the author made back when it was posted.

Yep, I was the author. Live and learn.

Matt