The Hall sensors are placed inside a motor 120 degrees apart. When the magnetic rotor passes from the sensors it will energize them every 60 degrees within an electrical cycle. That means that we will have 6 Hall transitions every time the rotor follows the stator's magnetic field for an electrical cycle.

From the arrangement of the Hall sensors within the motor, we will encounter the following six states:


Hall AHall BHall CHall status

The Hall status is the binary to decimal transform of the Hall signals. E.g. 001 = 1, 100 = 4 etc. Hall C is the most significant bit.

To determine that the Hall sensors are working propery, the following conditions should apply:

  • The Duration of every Hall state is the same
  • All hall transitions from 1 to 6 are observed
  • The Hall status of 0 and 7 are missing, since they are not valid
  • The signals sequence is one of the following two, depending on the motor direction: 1-3-2-6-4-5- or 5-4-6-2-3-1

Different sensor failure modes can have different impact on the motor rotation. For example if the sensors are misaligned - and so the Hall states duration is not the same - the motor current might not be stable. If one of the Hall signals is missing - the Hall status will not get all the states from 1 to 6 - and the motor probably will not be able to rotate at all. 

example of misaligned Hall sensors

Example of Hall B signal missing

The Hall state can be monitored in the Diagnostics tab during motor/sensor setup.