3
\$\begingroup\$

I am designing a driver for a sensorless bldc motor and I have found these two types of motor configurations. I attach images.

Img 1:

enter image description here

Img 2:

enter image description here

Both are bldc sensorless motors?

How can I know the difference between one physically?

If the 3 power cables and 3 smaller ones come out of a motor, are we talking about the configuration of image 2 and if only 3 of the configuration of image 1 come out?

\$\endgroup\$
  • \$\begingroup\$ The second one has sensors, hall sensors to be precise. \$\endgroup\$ – Marko Buršič Feb 22 at 14:07
  • \$\begingroup\$ @MarkoBuršič has it : one of those sensorless motors isn't sensorless. But if you need sensorless, ignore the sensors. \$\endgroup\$ – Brian Drummond Feb 22 at 14:50
6
\$\begingroup\$

Q: Both are bldc sensorless motors?

A: No, only the first one is a sensorless BLDC motor. The motor in image 2 has three Hall sensors (the ones enclosed in your red circle), thus it's not sensorless.

Q: How can I know the difference between one physically?

A: If you were to open up a sensored BLDC motor you will find three Hall sensors inside. A sensored BLDC motor also has 3 "small" cables for the signals of the Hall sensors, whereas a sensorless BLDC motor has only the three "thick" power cables.

Q: If the 3 power cables and 3 smaller ones come out of a motor, are we talking about the configuration of image 2 and if only 3 of the configuration of image 1 come out?

A: Exactly

By the way, if you're designing a sensorless inverter you don't need to use the Hall sensor signals, you can just only ignore them.

|improve this answer|||||
\$\endgroup\$
  • 2
    \$\begingroup\$ The sensor cable usually has at least 5 wires because the Hall sensors need power. \$\endgroup\$ – Bruce Abbott Feb 22 at 18:36
  • 1
    \$\begingroup\$ You're right, thanks for the comment, I was just restricting the discussion to the presence/absence of the signal wires of the Hall sensors. \$\endgroup\$ – Javier-Acuna Feb 23 at 11:15

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.