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The torque constant of recent T-motor actuators is no longer 0.14 Nm/A

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Senthur Ayyappan
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Hey everyone, 

After running a few tests, we found that the torque constant of recent T-motor actuators has changed and is no longer 0.14 Nm/A--we can confirm this is true, and the torque constant is now ~0.11 Nm/A (Q-axis). We've attached a picture of the sinusoidal back-EMF voltage, and the calculation of the q-axis torque constant from the line-to-line sinusoidal EMF.  These changes appear to be driven by a change in T-motor's properties, and is noted on Dephy's website (although Dephy states that the direct drive circular actuators should still have a torque constant of 0.14 Nm/A).  The website for T-motor still shows the wrong info.

The following code snippet calculates the q-axis torque constant from the line-to-line measurements obtained from the attached picture:

v_ll = 21.0; %V
freq = 849.2; %Hz

dtheta = (freq * 2 * pi)/(21);
kt = v_ll/(sqrt(2/3) * dtheta);