[archiver]

Posted by Ken Leung at 2/15/2001 4:26 PM EST


Student on team #192, Gunn Robotics Team, from Henry M. Gunn Senior High School.


In Reply to: Motor Torque (gains)
Posted by Alex on 2/15/2001 3:35 PM EST:



I am not so sure you can increase the current to the motors, because there are certain rules that limit what kind of circuit breaker you can use on the motor. Those circuit breakers are already limiting how much current you can have on the motor. Plus, this is just another way of making sure people don't max. out the power of motor if they have the engineering skills to, or have the resources to afford to replace motors, but also, it's a simple rule to prevent unnecessary damages to the motors.

As most teams do, you should look into adding mechanical modification to the output of the motors, instead of changing around current and electronics. Usually most teams gear the motor's motion slower so that they can get more torque out of them. Remember, Power = force x velocity or torque x angular velocity.

By cutting off 4" from the arm, you already increase torque quite a bit.

About The relationship between torque/speed/power/current, I know that there is a linear relationship between torque and current, and that the more current you have, the more torque you can get. The linear relationship between torque and speed is the exact opposite.

As for the relationship between power and torque, all I know is that at the beginning when you have an increase of torque, you also have an increase of power. But then it reaches to a mid point where power output have a change of zero, and start decreasing until a point where you have maximum torque but really little power, meaning very little speed (stall torque). All I know is that you want to keep your range of torque in the interval where your power is at maximum or near the maximum.

You should really look at the power point presentation in the white paper section by Michael Ciavaglia and Joe Johnson about all these. That is if you haven’t do so…

I am sorry I can’t offer much help here because I only know about characteristic of motors, and can’t really apply that knowledge to making the situation. If you already when through those presentations already, then assume I didn’t say anything. Can someone please help out here?