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Tic T825 motor settings and motor locking up


Since I am new to stepper motors this is probably a silly question that everybody else knows the answer to. BTW Pololu thanks for the quick delivery on my order.

Unlike a brushed motor, when applying slight torque to the output shaft a brushed motor will recover and continue to spin but I noticed the stepper motor comes to a dead stop and locks up.

The holding torque is much stronger than the running torque?

I am assuming this must be inherent in stepper motors and not some adjustment I need to make to the Motor Settings using the Tic software?




It does not seem normal for a stepper motor to lock up with too much applied torque like that unless it is being commanded to step at a fairly fast speed. If you use a very slow step rate, does your motor still lock up?



You are correct, slower speeds provide higher torque. Using the Tic software I had to lower the velocity to 10000 which is pretty slow. I was using the #1476 motor which is 55 oz-in. Do you think that going to the #1472 which is 125 oz-in will give me better torque at higher speeds?


To compare how much torque each of those motors can provide at various speeds, you should look at the pull-out torque curves in each of their datasheets. You can find the datasheets for each of those motors on the resources tabs of their respective product pages:

In this case it seems like your current motor might handle faster speeds without losing torque better.

In general, using a higher motor voltage can also help get higher torques at faster speeds. What is your input voltage? What is your current limit set to?



Hi Claire, thank you for pointing me to the Pull out torque curve, that was very helpful.

Currently I am testing with 9.6 volt NiMH batteries and a 12 volt 1.5 amp power supply. I’ve noticed better performance at higher currents. I started low and worked up 512 mA through 992 mA. Also, 1/32 step provides better torque at higher speed then any of the other steps.

Thanks for your help!


Increasing your input voltage should also help you get better torque at high speeds. It is pretty common to use 24V or higher in stepper motor systems.



Thanks for the help on this. I’ll experiment with the higher voltages to see if this will be suitable.