Motor Calcs with <100% PWM output

[Nemo]

How do I adjust a motor speed calculation if my DC motor controller is set at, say, 50% PWM output? Do the stall torque and free speed go down proportionally?

[Ether]

Originally Posted by Nemo

How do I adjust a motor speed calculation if my DC motor controller is set at, say, 50% PWM output? Do the stall torque and free speed go down proportionally?

As a first approximation, yes.

http://www.chiefdelphi.com/media/papers/2432

[Nemo]

Thanks! You've posted all sorts of useful things here - that is much appreciated.

[Joe Ross]

One other thing to consider is that without additional compensation, 50% pwm on a jaguar will be close to 50% speed. On a victor, it will be significantly faster.

[Nemo]

Originally Posted by Joe Ross

One other thing to consider is that without additional compensation, 50% pwm on a jaguar will be close to 50% speed. On a victor, it will be significantly faster.

This is a good point. I'm actually looking at this for FTC using Hitechnic DC motor controllers; getting more than 2:1 or 3:1 reduction using Tetrix parts gets bulky, so I am figuring out when it makes sense to do part of the speed reduction with lower PWM output. After your comment, it occurs to me that I don't know how linear those controllers are, so maybe we'll have to do a bit of rough testing.

[Ether]

FWIW, the Victors get a lot more linear once you put a load on them.