Quote:
Originally Posted by Monochron
Ah okay, wow that is really different than what I was thinking. I'm not entirely sure what you would use that wattage for.
Is max mechanical power useful for calculating force applied to an object or something similar to that? I have an equation on the sheet for calculating linear force based on the stall torque of the motor, do you know of another one I could add using max mechanical power? Or an example of what knowing the max mechanical power can tell you?
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Power is work over time. You can calculate how much mechanical power it takes to do a certain work in a certain amount of time. The power rating of a motor will let you make a first approximation of whether or not motors can meet your objectives regardless of gear ratio.
Let's say you're trying to lift a 50kg mass robot 1 meter off the ground in 5 seconds. You can quickly determine the work this takes - the negative of change in potential energy. In this case, the energy required to do the work is (50 kg)(9.81m/s^2)(1 m) = 491 J. Doing this much work in 5 seconds means your power requirement is 98.1 watts, at the minimum. This doesn't account for various efficiency losses.
What can you do with this number? Compare it to the motor spec sheet. For example, with a perfect gear ratio, can a window motor possibly lift 50 kilograms 1 meter in 5 seconds? No, as its max power is far less than 90 watts. Could a mini-CIM? Absolutely, its max power is more than double the requirement. From here, you would move on to figuring out a good gear reduction for this motor to best accomplish your task while meeting your other constraints.
Practically, max power is a quick way of determining which motors are capable of which jobs. Bigger number means more powerful.