[Paul Copioli]

Originally Posted by Knufire

Paul Coipoli did write a spreadsheet with the motor combination equations in the thread that Ether linked earlier:
http://www.fightingpi.org/Resources/...culations.xlsm

His MSC seminar also discusses the topic (link skips straight to the motor combining section): http://www.youtube.com/watch?feature...xpYnqJ8#t=1479

I am very confident in the combination equations in this spreadsheet. I developed it for the exact same reason the OP asked the question. These combinations and current draw calculations match up very well with my multiple motor dynomometer testing.

It does 2 and 3 motor gearboxes and also allows you to take a snapshot at any particular speed condition. One other subtle thing it does is allow you to put your entire gearbox gear ratio into the input section so the combined motor equation is your actual gearbox output equation.