Quote:
Originally Posted by sastoller
My big takeaway from all this is that the SD540 is unnacceptable for use in FRC robots due to the brown-out issue. In addition, with it's high output resistance, it would no doubt, would get very, very warm in a stall condition. You can estimate the power that is turned into heat in the output devices of the SD540 to be nearly 50 Watts in the resistive load test 3, at 11.20 volts. With a CIM motor, the SD540 would be dissipating ~100 watts of energy as heat. I wonder how long it takes to melt (can someone test and post pictures please)?.
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sastoller : I think you need to brush up your Knowledge of "Switch Mode Operation" You cannot calculate the resistance just like R= V/I, in today's switching technology used everywhere. If you apply your theory to your cell phone charger your charger should be dissipating ridiculously large amount (120V-5V) * 1amp = 115W (120V input, 5 V output and 1 amp current) but is is not doing that. All it means is that it is not 100% ON but around 95% ON.