3

The brushes wear out in brushed motors and their performance decreases until they stop working, but brushless motors have fewer parts in contact and thus don't wear out nearly as fast.

Does the performance of a brushless motor decrease over time or does its performance remain practically the same throughout its life?

6

Like most things, it depends on how you treat it.

As far as I know, you should never need to worry about a brushless motor wearing out, especially for our purposes where we will likely demolish them before they have a chance to wear out.

You do have to watch out for the bearings and magnets, however.

With the bearings, like any mechanical component, they will eventually wear down, however this will likely not be for a long time. It is still a consideration, though.

You also have to watch out for the magnets.

Under normal circumstances, the magnets are fine to last a long time, however excessive heat can eventually demagnetise them, leading to reduced performance and eventually the motor not producing enough power for us to use.

If anyone has any other ideas or wants to correct me, please do!

| improve this answer | |
  • Good answer. I would add that an easy way to check for demagnetization is to check the no-load RPMs. You'll want to check the no-load RPMs when. You first get your motors by running them to full throttle at a defined voltage, and keep a record. If you have a bench supply and are using a flight control firmware that supports rpm logging via ESC telemetry this is fairly straight forward. Then just check every so often. If the no-load RPMs are increasing, you're losing magnetic field strength due to heat damage. – QuadMcFly Apr 21 at 11:26
  • @QuadMcFly excellent idea - though is this supported on ESC firmwares other than BLHeli_32? If so I’d be very interested in seeing how to do this. – Drones and Whatnot Apr 21 at 11:29
  • Yes, it would work on KISS ESCs as well, as they also support RPM telemetry. It doesn't need to be extremely low latency just sustained. I believe the VESC project also supports some sort of RPM monitoring, which is used by some larger drones. – QuadMcFly Apr 21 at 11:34
  • @QuadMcFly good to know - thanks! – Drones and Whatnot Apr 21 at 11:36
2

Not really. Since brushless DC motors have no brushes to get worn out, they represent a huge leap forward in technology. Brushless motors have significantly higher efficiency and performance, and a lower susceptibility to mechanical wear than their brushed counterparts. They can last 10,000s of hours if used correctly and not overheated etc.

| improve this answer | |
  • 1
    What about demagnetization? – ikrase Apr 21 at 6:59

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.