Placement angle mistake in ST Manual

SRedd.5 · ‎2023-07-11

I am referring to the above diagram and the placement angle delay is mentioned as 270. How is it? According to me it shall be 90Degrees.

Gael A · ‎2023-07-12

Hello SRedd.5,

It depends on the reference used to calculate the delay. Here, we are taking Phase A (where the BemfA is at maximum value) as reference. The diagram shows H1 is 90° behind Phase A, which would be an angle of -90°. However, H1 is also 270° before Phase A, and as we prefer positive value, we will set +270° instead of -90°.

If our reference was H1, we would indeed have a delay of +90°.

Hope this will help,
Gaël A.

If you agree with my answer, please consider accepting it by clicking on 'Accept as solution'.

Hope this will help,
Gaël A.

View solution in original post

Gael A · ‎2023-07-12

Hello SRedd.5,

It depends on the reference used to calculate the delay. Here, we are taking Phase A (where the BemfA is at maximum value) as reference. The diagram shows H1 is 90° behind Phase A, which would be an angle of -90°. However, H1 is also 270° before Phase A, and as we prefer positive value, we will set +270° instead of -90°.

If our reference was H1, we would indeed have a delay of +90°.

Hope this will help,
Gaël A.

If you agree with my answer, please consider accepting it by clicking on 'Accept as solution'.

Hope this will help,
Gaël A.

SRedd.5 · ‎2023-07-12

I really need help on the below issue, i have captured the 3 hall signals and the Bemf and the Hall 1 signals as shown. I have run the motor in clockwise direction, as per the waveform the i could identify the H1, H2, H3 waveforms. I took the A+, B- BEMF waveform and the hall H1 waveform and the phase difference is -90. Since i took line voltage Bemf and is leading the phase voltage i calculated the delay as -60. When i give -60 the motor does not run, but only if i give 60Degrees it runs but with noise seem to be unstable. Please help to resolve the issue.