Quote:
Originally Posted by DMetalKong
The biggest thing that I am confused about is how to combine the curves of the two motors considering they have such different performance characteristics (max torque, current at stall, free rpm, etc.). What exactly is the process for matching things up?
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Gear the higher speed motor down so its free speed matches the free speed of the slower motor. Then scale the geared motor's stall torque up by the same factor and add it to the ungeared motor's data.
Take a CIM and an RS550 for example. Gear the RS550 down by 3.63 so its free speed is 5310, same as CIM. Its stall torque is now 3.63 times greater, or 251 ozin.
The motor curve for the combination would be:
free speed: 5310 rpm
free current: 2.7amps + 1.4amps = 4.1amps
stall torque: 343 + 69.2*3.63 = 594 ozin
stall current: 85amps + 133amps = 219 amps.
The above is a good approximation. If you want to toss in some loss of efficiency for the gearing that complicates things a little. The gear ratio would be slightly different, the free current somewhat higher, and the stall torque less.