pic: Plywood 8WD Concept

[s_forbes]

Originally Posted by AdamHeard

Another way to visualize this is to extend the classic torque/speed graph to include negative free speed, you'll see the torque there is 2x the stall torque.

This looks like a sensible way to demonstrate the point. I did some googling for a bit to try and find an extended motor curve that goes into the negative rpm region, but haven't turned up any good results yet. I'd be interested to see how the power and efficiency curves fit on the negative side as well.

[Deke]

I would like to crunch some numbers here to see what kind of loading the cim pinions usually take, i have not looked at the numbers before to see where they stand. It seems to me that the simple and conservative way to approach this is to use the stall torque at a steady state, but there are some dynamics involved here. Now a question would be how much of an impact do the system dynamics play into the tooth loading? When the motors reverse is there a ramp or instant loading? Do the wheels slip? I think if those parameters can be modeled, an accurate calculation can be made regarding the loading.

Does that logic make sense or am I missing something?