pic: Plywood 8WD Concept

[Ether]

Originally Posted by s_forbes

Where's Ether?

MIA I guess :-)

I agree with Adam's analysis with one minor quibble: with 2x stall current you may not get 2x stall torque. Depending on the motor design, the magnetics may saturate before that. Does anyone have stall torque test data for CIM at 24 volts?

[AdamHeard]

Originally Posted by Ether

MIA I guess :-)

I agree with Adam's analysis with one minor quibble: with 2x stall current you may not get 2x stall torque. Depending on the motor design, the magnetics may saturate before that. Does anyone have stall torque test data for CIM at 24 volts?

Very fair point, and rather likely actually (that saturation occurs, leading to less than 2x but greater than 1x usual stall torque).

[AdamHeard]

Originally Posted by AdamHeard

Very fair point, and rather likely actually (that saturation occurs, leading to less than 2x but greater than 1x usual stall torque).

Also worth pointing out that in especially regards to drive with so many paired motors, you will have 4 or more motors trying to draw near double stall current, over 1000 Amps for 4 cims. This will cause a large voltage drop, until the current draw reaches an equilibrium with that. This will greatly reduce the Torque.

My hunch is you will still experience greater than 1x Stall torque at nominal voltage, but not the classical 2x I originally stated.

[magnets]

Originally Posted by AdamHeard

Also worth pointing out that in especially regards to drive with so many paired motors, you will have 4 or more motors trying to draw near double stall current, over 1000 Amps for 4 cims. This will cause a large voltage drop, until the current draw reaches an equilibrium with that. This will greatly reduce the Torque.

My hunch is you will still experience greater than 1x Stall torque at nominal voltage, but not the classical 2x I originally stated.

Your hunch is definitely right. A robot that doesn't have enough torque to spin its wheels when its up against a wall can break traction with the ground if you try to stop it too quickly.