Horsepower of Kit Motors?

[Al Skierkiewicz]

To answer many of the above questions...
The different motors we used were matched to different transmissions so that the wheels were close to match. Any fine tuning could then be done in software. Knowing which side the drills were on then set what side of the robot was used for power, pushing, etc.

Using watts for motor output power helps solve a number of problems in design. You know what the output power is and you can measure the input electrical power, so with a little calculation you can determine efficiency. Power out/power in=efficiency. So what does that tell you? The power lost in the conversion has to go someplace. The result is heat. So in the case of the Bosch motor running at 376 watts out with 672 watts input, efficiency at 56%, then 296 watts go into heat. Yes that's like three 100 watt light bulbs in each motor doing nothing but generating heat. That is the heat that changes the motor internal resistance, melts the bearing lubricants, detaches the fan and unsolders the motor wires. In many cases in electrical systems, it is very important to get rid of the heat generated in the system. Things like CPU heatsinks and power supply fans in your computers prevent that heat from building up to point where the physical properties start to change. In solid state electronics, the heat generated internally can cause more current to flow, which in turn causes more heat, and so on. The tech term is "thermal runaway" and many devices are designed to shut down when the temp gets too high. The three terminal regulator, 7805, will cutback on current or shut down completely if it gets hot, for instance.