MMM drive frequency

[Pdelcast]

We don't allow changing the frequency on the MM or MMM simply because there are so many "novice" users who will look at the feature and assume higher is better...

Higher frequency drive is harder on the ESC, but easier on the motor. Lower frequency drive is easier on the ESC, but harder on the motor.

We chose a frequency that works well with pretty much anything from large outrunners to small slotless motors. It is a bit of a compromise, but we don't have to worry about someone pushing up the frequency to 56khz (which is the maximum PWM frequency on our Phoenix-ICE airplane controllers) and then pushing an ESC past it's maximum power. At lower frequencies, an ESC can handle overcurrent quite well -- at higher frequencies the ESC can be damaged much easier.

Our "compromise" frequency is about 12.5khz, which works very well in practically all circumstances.


Oh, and the frequency is variable during startup (part of our patented algorithm for low speed brushless motor start) and then becomes fixed at higher RPMs. During startup, frequency is dependent on motor inductance.


Lutach -- I'm surprised you saw ANY difference between the MM and any other controller on the Mega motor. Tekin uses a similar run frequency to Castle, and Hobbywing uses a lower frequency (which would usually make a motor run hotter...) Hobbywing also doesn't track back-EMF very well compared to the MM, so if anything, I would expect the Hobbywing to run the motor slightly warmer than the MM. Could there have been some odd programming (very high timing for example?) on the MM?

[lutach]

Originally Posted by Pdelcast

Lutach -- I'm surprised you saw ANY difference between the MM and any other controller on the Mega motor. Tekin uses a similar run frequency to Castle, and Hobbywing uses a lower frequency (which would usually make a motor run hotter...) Hobbywing also doesn't track back-EMF very well compared to the MM, so if anything, I would expect the Hobbywing to run the motor slightly warmer than the MM. Could there have been some odd programming (very high timing for example?) on the MM?

I really don't know what caused the heat issues and I tried all the settings possible at that time. Right now I'm actually running (Testing) my micro 4 pole motor with a Tekin R1 and there's no heat issues at all.

I'll be getting in toch with you so we can work on some designs I have in mind.