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Electrical RPM of BasicESC

I am using the BasicESC to control a Maxon brushless DC motor. I can run the motor at its no-load speed of around 9,000 RPM. It has 1 pole-pair, which tells me the BasicESC has an eRPM of around 9,000. I would like to run a motor with the same no-load speed but with 2 pole-pairs, but I think it will run at half its no-load speed with this ESC. Can I increase the eRPM of the BasicESC to use the new motor? The BLHeli_S firmware datasheet says it can go to 350k eRPM.

Thanks in advance!

Hi @nhetherington,

It sounds like there are several inaccurate assumptions/misunderstandings in your initial question, and there also may be an XY problem involved as well. I will do my best to clear up any confusion and answer the intent of your question, please let me know if I misunderstand.

The maximum motor eRPM capability of an ESC is a fixed number determined by the ESC’s hardware and software capabilities. Beyond this point, the ESC cannot keep up with motor commutation, and cannot effectively drive a motor. It is a fixed limit.

There is no relation between number of motor pole pairs and max ESC eRPM that will affect no load or max motor RPM.

eRPM can be determined by the following equation:

(number of poles/2 * RPM) = eRPM

If you are using a motor with a maximum mechanical RPM of 9,000, and two pole pairs:

(2 * 9000) = 18,000 eRPM, which is far less than the 350,000 eRPM limit of the Basic ESC.

Your motor is well within the eRPM commutation limits of the BasicESC.


Thanks Adam! That is clear to me.