mamba max 6900 limitations

[Pdelcast]

Originally Posted by 1maxdude

Yes, but real world setting, do you think under load it is really seeing that kind of rpm? The voltage in the battery will drop as soon as you go. Perhaps if you were geared down it would run at high rpm, but in my case of doing all out speed runs, it takes some time to get it at high speeds and I don't think I've been able to top it out due to the car being too far away to want to keep going that fast. I'm starting to believe that without a ubec, the temps of the esc will get too hot too fast. The 5700 probably pulls less amps than the 6900 and if you combine that with higher voltage, the 6900 will probably put the esc at unsafe operating temperatures whereas the 5700 won't and keeps it within its recommended range.

Actually temps depend almost entirely on gearing -- if you use a low enough gear you can keep the 6900 and ESC pretty cool on 3S. The real issue is the bearings and the magnet, you can get a catastrophic magnet failure at above 75000RPM or so. You wouldn't normally see that RPM, but if you pull full throttle during a jump, for example, the motor will unload and hit full RPM pretty quickly.

That said, the newer magnets are handling around 100K RPM without any problems, but the bearings also can't take that RPM (even the Koyo CNC Japanese bearings on the newer CM36 motors) -- so to be safe, we make 60,000 the top allowable RPM.

[SunnyHouTX]

Originally Posted by Pdelcast

Actually temps depend almost entirely on gearing -- if you use a low enough gear you can keep the 6900 and ESC pretty cool on 3S. The real issue is the bearings and the magnet, you can get a catastrophic magnet failure at above 75000RPM or so. You wouldn't normally see that RPM, but if you pull full throttle during a jump, for example, the motor will unload and hit full RPM pretty quickly.

That said, the newer magnets are handling around 100K RPM without any problems, but the bearings also can't take that RPM (even the Koyo CNC Japanese bearings on the newer CM36 motors) -- so to be safe, we make 60,000 the top allowable RPM.

Hey there Patrick, does CC plan on making a sub-3600 kV motor with those 100,000 rpm magnets? If you do, I will buy at least 3.

[Mister-T]

Originally Posted by SunnyHouTX

Hey there Patrick, does CC plan on making a sub-3600 kV motor with those 100,000 rpm magnets? If you do, I will buy at least 3.

Take a Tekin reline 632 (3200 kv) or 537 (3700 kv) they are based on the same type of design and work flawlessly with CC controler