DC motor model performance issue

I am using the DC model from SimPowersystem in a closed-loop control, and I encountered a strange problem. The DC motor is configured as permanent magnet DC machine and all motor parameters are taken from one DC motor datasheet. With everything else unchanged, specifying "Torque constant" in motor parameters or "Back-emf constant" would result in two totally different results. I attached the parameter and result screen captures and would anyone please advise why it could happen this way?

Answer 1

[Sabin]

The DC Machine expects the torque constant to be equal to the voltage constant. However, this is not the case leading to different results.