[Joe Johnson]

Originally Posted by ChrisH

... I design mechanisms to operate at 75% of free speed and 25% max torque. This leaves plenty of margin power (approximately 50%) and with the high rpms you get plenty of cooling air through the motors. By operating on the fast side of max power, when things bog down, you actually get an increase in power....

ChrisH

I KNEW I liked you, ChrisH. Another great thing about designing your machanism to run on the fast side of the power parabola is that the efficiency is higher on that side. That means more power turned into spinning shafts, less into heat.

ANOTHER benefit is a controls benefit. It is much much easier to control something when its free speed is only 1/3 faster than its designed loaded speed. The controller can be must less critical because the arm or whatever will not 'over run' the controls if the load vanishs (e.g. you were lifting 40 lbs of tetras and you just dropped the stack).

Joe J.