I agree with the advice the others here have given to reduce the heat generated by the motors, but if you can’t or won’t solve the overheating through those methods, you can still squeeze a bit more power out of the motors than even with freeze spray.
If you really want the maximum performance, you could use quick-swap motors, and store the spares in a small freezer (or a cooler with dry ice.) That way the cold can fully penetrate to the core of the motor and you can achieve sub-ambient temperatures (technically the ambient heat can fully escape.) It won’t magically double your performance, but you might get another 30 seconds of runtime. Keep in mind you run the danger of causing condensation to form inside the motor, which could cause permanent damage. I would not recommend this strategy in a very humid environment.
@Bob132: Oh man, picture you walk into the event, go to your pit, put a cool looking briefcase on the table, open it with a cool click and a hiss, cold steam comes out, inside: nicely lined up perfectly chilled V5 smart motors. Doing it…
Welcome to the world of engineering, which ultimately is solving the problem within the constraints that you have to work with. The overheat protection is there for a reason. Sometimes compromises have to be made. You might need to either not play such heavy defense to protect your motors or give up trying to climb on the platform with 2 or 3 mobile goals or change your robot in a way that will allow you to do what you want, possibly sacrificing some speed in the process. Good Luck with your choices and your season.
You can also do some programming changes to reduce your robot’s chances of overheating in a match
- Switch joystick commands to control motor voltage instead of motor velocity
- If you already use motor voltage, then limit the max voltage to 85-95 pct.
The motor velocity commands will use a pid controller to try and get to the exact velocity commanded by the joysticks, which causes extra changes in voltage even at constant speeds. By just commanding a certain voltage to the motors, the voltage will not fluctuate randomly, which saves quite a bit of heat. Limiting the max voltage will definitely cause your motors to not overheat, however, the robot’s max speed and torque will decrease by ten percent or so. There should still be enough torque to drive the robot on the platform. Test by changing the velocity commands to voltage first (if you have not done so already) and then see how high you can keep the voltage while keeping the motors from overheating.
Another option is to limit max current to the motors.
Use vex::motor::setMaxTorque(value,units) to set it in percentage, current, or torque units.
Or in PROS use pros::Motor::set_current_limit(std::int32_t limit).
Then it should limit the current, thus reduce the amount of heating.
And driver can have a turbo override button to increase the limit to 100% when the button is pressed, then go back to 75-80% when it is released.
With proper training drivers can be very skillful to utilize turbo button only when it is really necessary.
[quote=“Jon_Jack, post:16, topic:94498, full:true”]
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2) Reduce the amount of current your motors are drawing during the course of the match.
… With DC motors torque and current have a proportional relationship. …[/quote]
Important to note that heat losses are proportional to the current squared. So, 2x current = 4x heat.