How to test the max torque of motor

1

Hi everyone,

I’m testing a TMotor MN8014 100KV (21 pole pairs) with ODrive Pro via the GUI. I’ve set the torque command up to 5 Nm, but I’m observing the following issues:
The motor current shown in the GUI never exceeds ~20A, despite higher current limits being configured.
The DC power supply reads only ~0.7A at 48V, which seems far too low for the commanded torque. Most critically, the motor’s actual torque output seems to max out around 2 Nm, even when 5 Nm is commanded.
Could someone clarify the relationship between the motor current reported in the GUI and the actual DC current drawn from the supply? And why might the system not be drawing enough current or producing the expected torque, despite being capable of more?

Appreciate any help or insights!

Thanks!

2

Hi!

Supply current does not equal motor current – motor current is (almost) always greater than supply current. Motor current is the torque-producing current.

You’re likely running into issues with the torque mode velocity limit, especially if you’re using default velocity limits and PID gains – the ODrive uses the vel_gain to derate the torque as a function of speed, when enabled (which it is by default). Try raising the velocity limit, or tuning your velocity gains. See here for more info on the vel limiting: Controller — ODrive Documentation 0.6.11 documentation