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Sensorless Velocity Startup Fault

Question asked by Derek Cook on Jun 22, 2018
Latest reply on Jun 29, 2018 by Derek Cook



In my sensorless velocity project, I get a startup fault when I set the TRAJVEL Accel limit to 9000, and the Jerk limit to 900000. These are the limits I use in my sensored project so that I get to speed quickly. In the sensorless project with these settings, I get a startup fault. When I lower the accel limit to 1000 and the Jerk limit to 5000, the fault goes away. 


I know the startup fault is thrown when the startup block detects that the calculated flux is less than 50% of the rated flux. Is there also a defined amount of time you have to take to ramp the motor to speed in sensorless control? If so what is that? Also, what are the speed thresholds that the Estimator block takes over control. In the reference manual the estimator block looks to take over at 400 RPM?