Max and Nominal Torque for D6374 and other BLDCs

1

Hello

What continuous torque can the D6374 provide with an ODrive 3.6 or a VESC6? The max torque is given as 3.86NM but how long can that current be sustained, provided adequate cooling is implemented and the driver can sustain continuous peaks for some n seconds?

I read somewhere that max current is normally 1.6-2.0x times the nominal current but I found no evidence for this, I also read the torque derating curve but didn’t full understand the continuous ratings from it.

I had the same question for other motors as well. The R100 from tmotor specifies a peak torque of 11NM, and they told me it can be sustained for 2 seconds. What does this mean exactly, what happens after the 2 seconds?

I’m a bit confused regarding this, it would help a lot if you could help to clear this up.

2

Motor current is proportional to motor torque, torque [N-m] = phase current [A] * 8.27 / kv [rev/min/V]

The exception is for stator saturation, so at very high currents that equation breaks down

The recommendation is that you do not overheat your motors, the equation for power loss as heat is power [W] = phase current [A] ^ 2 * winding resistance [Ω]

So you can run the motor current to double the rated current for a short period of time, but it will be generating 4x the heat, and you should only run a motor continuously at half the rated current…so the burst current will generate 16x the heat that the motor should be able to run at steady state