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DRV10975: SPEED vs RPM

ACGUY
Guru 11170 points
Part Number: DRV10975

Hello E2E,

Our customer is using the DRV10975EVM. They adjusted motor rotational speed on GUI. Actual motor rotational speed is not as linear as SPEED value.

Is it an original characteristics of motor? or does it need a separate correction?

Regards,
ACGUY

  • 0
    TI__Mastermind 24415 points

    Hi ACGUY,

    Thanks for posting your question in MD forum. The motor speed in RPM that is displayed in the GUI is not correct and this is a known issue. Please do not consider reading the motor speed in rpm from the GUI. For accurate results, it is recommended to read the Motor electrical period and then calculate the electrical speed of the motor (Hz) manually by calculating the inverse of Motor electrical period and then convert to mechanical speed in RPM. Another easy way is to measure the frequency of the FG signal output. Is the SPEED that is plotted in x-axis Electrical speed in Hz? 

    Regards,

    Vishnu.

  • 0 in reply to Vishnu Balaraj
    Guru 11170 points

    Hi Vishnu,

    Thank you for reply. Please let me know what the modified parameter of that device by SPEED value of GUI. And why the increased steeply for actual motor rotational speed? Is it a characteristic peculiar of the motor?

    Regards,
    ACGUY

  • 0 in reply to ACGUY
    TI__Mastermind 24415 points

    Hi ACGUY,

    I didn't quite capture your question about the modified parameter. Can you plot the motor speed that is calculated using motor period (as mentioned in my previous post) and plot the graph between this speed and the actual rotational speed? I just want to see if we still see the same non linearity when we plot the motor speed calculated using motor period. 

    Regards,

    Vishnu.