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# ST Motor Workbench - Placement electrical angle

Associate II
Posted on March 05, 2016 at 22:10

Could you describe how to set ''Placement electrical angle''. The default value in ST Motor Workbench is 300 degrees.

I have an 8-pole motor with 120 degree spaced hall sensors. I have this set to 60 degrees based off information I found online and I get the most torque at that setting as well. I'm interpreting it as the angle difference between different hall states.

I ask the question because the value of ''Placement electrical angle'' can be from 0 to 359 degrees and I'd like to understand when that changes.

From my understanding a value other than 60 degrees shouldn't work properly if using 120 degree spaced hall sensors...but that must not be the case hence the option in ST Motor Workbench.

Regards,

Sagar
7 REPLIES 7
Associate II
Posted on March 08, 2016 at 20:14

bump

Senior
Posted on March 14, 2016 at 10:28

Although the numerical value can go from 0 to 359, the only real options are 60 and 120 degrees. To me it seems unlikely that your motor runs better with the ''wrong'' setting.

From: s.ptl.05

Posted: Saturday, March 05, 2016 10:10 PM

Subject: ST Motor Workbench - Placement electrical angle

Could you describe how to set ''Placement electrical angle''. The default value in ST Motor Workbench is 300 degrees.

I have an 8-pole motor with 120 degree spaced hall sensors. I have this set to 60 degrees based off information I found online and I get the most torque at that setting as well. I'm interpreting it as the angle difference between different hall states.

I ask the question because the value of ''Placement electrical angle'' can be from 0 to 359 degrees and I'd like to understand when that changes.

From my understanding a value other than 60 degrees shouldn't work properly if using 120 degree spaced hall sensors...but that must not be the case hence the option in ST Motor Workbench.

Regards,

Sagar
Associate II
Posted on March 17, 2016 at 18:51

Thanks. Yeah I figured so. I'm using 60 degrees. Its just odd in the UI they have the default set to 300.

Senior
Posted on April 01, 2016 at 14:56

Ciao

I'm trying to clarify the meaning and difference between ''Sensor displacement'' and ''Placement electrical angle''.

The ''Sensor displacement'' is related to the angle between sensors. And this is usually 60° or 120°. This mean that physically the three sensors are displaced in the space at 60° or 120° generating different sequences of signals.

60° degree generates H1 Fall then H2 Fall then H3 Fall then H1 Rise  then H2 Rise then H3 Rise and so on

120° degree generates H1 Fall then H2 Rise then H3 Fall then H1 Rise  then H2 Fall then H3 Rise and so on

The ''Placement electrical angle'' defines the displacement of the three sensors respect the stator. Because the FW need to know the angle that corresponds to each rising/falling of the sensors. This is not let's me say an ''absolute value'' that you can read in the data sheet of the motor because you have to define also a convention with the name (and angle of each) stator phases. So our suggestion is to calculate manually this parameter (to be set in the firmware to get the correct angle measurement from the HALL sensors) directly in your system (so after you have connect the motor phases to the inverter establishing the angular system of the stator). Some details and procedure to measure this parameters is explained in the FW user manual.

Ciao

Gigi

Associate II
Posted on April 04, 2016 at 17:08

Hello

there is a mistake in the UM1052 Section 8.3

My Hall Sensors are placed with 60° on the Motor, but i have to choose 120° in the Workbench to get the motor spinning. The Signals from my 3 Hall sensors are the same signals like 120° in the UM1052.

friendly greetings

E.John