Electric motor temperature sensor locations

[geneiusxie]

Hi guys,

I'm trying to design a brushless motor for an EV with temperature sensing for both the copper coils in the stator and the permanent magnets in the rotor, but I'm not sure how to add a temperature sensor on the neodymium magnets in the rotor. Wouldn't the high levels of varying electromagnetic fields throw the readings off? Or would the system have to compensate for that somehow, e.g., using a low pass filter?

Of course, the bigger question would be whether the permanent magnets ever generate significant (if any) heat during normal operation anyway. :)

-Gene

 

[TurtleMeister]

I don't know about the neodymium magnets. But I once worked for an AC induction motor manufacturer, and for lab testing, the temperature sensors were always placed in the windings. That's where the most heat is generated. I don't recall sensors being placed on the stator or rotor. We used thermocouple temperature sensors and compensation for magnetic fields was not required.