What is the best way to destroy the Duet2 motor driver?

dc42

@kotuo said in What is the best way to destroy the Duet2 motor driver?:

Green point (length excluding shaft) 39mm

Thanks, it's a 39mm Nema 17 motor then.

To get an idea of the characteristics, go to https://www.omc-stepperonline.com/nema-17-stepper-motor/. Set he unipolar/bipolar filter to Unipolar, the Body Length filter to a range that is close to the motor length e.g. 39 to 40mm, and set the Phase Resistance filter to a value that covers the 11.6 ohm resistance that you measured.

The closest one I found was this one https://www.omc-stepperonline.com/nema-17-stepper-motor/nema-17-bipolar-1-8deg-36ncm-51oz-in-0-85a-5-4v-42x42x39mm-4-wires. It has the same length but the phase resistance is 6.3 ohms.

To account for the different in phase resistance, we can assume that for the same motor size, inductance is proportional to phase resistance, rated current is inversely proportional to the square root of phase resistance, and phase voltage is proportional to the square root of phase resistance. This suggests the following approximate values for that motor:

Inductance 18.4mH
Phase voltage at rated current 7.3
Rated phase current 0.63A

EDIT: is that the Z motor? Is there just one Z motor, or are there two? If there are two, how have you connected them to the Duet?

dc42

@kotuo said in What is the best way to destroy the Duet2 motor driver?:

@veti Thank you for pointing this out.
I have no choice but to change the order of the cables because the cables I am using are twisted on the motor side and I do not have the terminals on the motor side.

There are at least two different phase pinouts used on stepper motors with 6-pin JST connectors. This means that if the cable was not supplied with the motor, the colours may well be wrong, as you have discovered.

kotuo

@dc42 Thank you for your reply.
I am using only one Z axis.

dc42

@kotuo what motor current have you set for the Z axis in your M906 command in config.g? You will need to use 600mA or less with that motor. If you set a much higher current, then you can expect to see those "phase may be disconnected" warnings, because the drivers will be unable to provide the requested current to that high resistance motor.

kotuo

@dc42 Thank you for your reply!
I will lower the motor current to 600 with RRF and upload the zip file to Duet.