X-NUCLEO-IHM11M1(STSPIN230)

[NIVI]

 

Hi,

We've been evaluating our BLDC motor with the X-NUCLEO-IHM11M1 board, and I wanted to share some observations and seek clarification on certain aspects.

We noticed that the motor rotates smoothly only when the six PWM inputs are connected to the oscilloscope. When the PWM inputs are not connected to oscilloscope, the motor encounters difficulties in running. To address this, we implemented pull-up and pull-down resistors to the PWM inputs, and the motor now works smoothly.

Could you please provide insights into why this behavior occurs?

Additionally, Please provide an explanation on the effects of adding pull-up and pull-down resistors.

We observed that the motor rotates in one direction when pulled up and in the opposite direction when pulled down.

 

[GMA]

Hello @NIVI,

Firstly, sorry for this late response.
Please, have a look at this post to ease the response.
What is your control board, and did you use ST Motor Control Workbench?
Could you check your control board PWM output settings to ensure that there is no phase on which phase output is in high impedance state?