[archiver]

Posted by Patrick Dingle at 1/7/2001 9:57 AM EST


Other on team #639, Red B^2, from Ithaca High School and Cornell University.


In Reply to: How do people get hot motors?
Posted by Elaine Owens on 1/7/2001 3:11 AM EST:



If I remember physics correctly, the amount of heat given off by anything is related to the amount of power used. This is also directly related to how fast your battery drains. As Woodie explained at the kickoff, there is a linear relation between torque and speed of a motor. He also explained that the power used is proportional to product of the torque and speed. In other words, the most power is used when there is a perfect tradeoff between speed and torque. Therefore, at a low gear, your motor has a lot of torque, and not as much speed. Since the heat (power) is the product of these two (say torque = 8 and speed = 2), the heat is torque (9) times speed (1), or 9. If there were a perfect tradeoff (torque = 5, speed = 5), then heat = 5 x 5 = 25, which is much greater than 9. The robots that will have the most heat (at least with the drill motors) are the ones that use a medium speed.

I think most times, however, there is not problems with the drill motors. I think most of the times the problems occur with the smaller motors. The problems occur when the smaller motors are continuously draining a lot of power. When designing components of your robot, I think it is a good idea to make sure the motors are geared down as much as possible. That way you get a lot of power w/out eating up tons of power.

Patrick

: Hi, I heard last year that some of the teams had a hard time cooling down their motors and that they kept getting hot. But for our team, last year our motors were fine. They barely felt warm. So I was wondering why some teams had problems with hot motors. Is is beacuse they ran the drill on the high gear....because we used the low setting for our robot(last year).

: Elaine