Quote:
Originally Posted by Chris is me
So... we saw smoke when we made our bare bones minibot try to climb, with a modest overgear (0.5:1). These things can't be stalled for even a half second, apparently? I have no idea what smoked or whether or not the motors still worked, but if the motors are that delicate...
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Let's take a second and do some *wait for it* real engineering.
To get the climb times we want, we have to run the TETRIX motors at 50% of their stall torque. Depending on gearing and weight, the robot will not run at perfectly 50%, so most bots are either on the close-to-stall or further-from-stall side of the power curve. A 0.5:1 ratio with 3" wheels is slightly on the closer-to-stall side for a 5-lb minibot, by my calculations anyways.
Given the experiences we've had with Banebots 550/545 and Fischer-Price 9012 motors, I'd say the burn out at stall of an TETRIX motor is perfectly aligned with what should happen. If we run the FP9012 at 50% of stall 100% of the time, it seems like simply thinking bad thoughts at the motor will burn it out when it hits a bump.
So Chris, you should be happy that your TETRIX motor smoked. It means you didn't do the engineering first -- and that fact will inevitably be a invaluable lesson at some point in your engineering career. It also means the sky isn't falling (whew).
If we're so concerned about motor (and wallet) longevity, the perfectly viable option is to not gear the thing for peak power. On the field, I'm sure we'd get 10 points every time we deployed; in the Elims, that's typically much better than a 50% chance the minibot nets either 30 points or 0 points (depending on how angry the motors are you keep running them so hot).