Quote:
Originally Posted by James Kuszmaul
I agree that you can calculate numbers for free speed, stall current, and stall torque for the combined motors. It makes intuitive sense why you could use the single motor equations... how do you prove...
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Perhaps it will help to present the math in a slightly different way. Attached is a derivation for the torque vs speed curve for the 3-motor combination directly from the torque vs speed curves for the individual motors.
It's straightforward algebra. It follows naturally from the assumptions that 1) all three motor speeds are the same (since they are mechanically linked) and 2) the individual motor torques are additive.
As you can see, the combination behaves exactly like a single motor with torque = Tstall*(1-Speed/Sfree), where:
Tstall = T1s + T2s + T3s
.... and
.... Sfree = (T1s + T2s + T3s)/(T1s/S1f + T2s/S2f + T3s/S3f)