BackFilp 360

maybe its just a warrnty thing because i think they have only had problems at 80-85k whitch is what novak claims with theirs

Novak2

Something to keep in mind when discussing "sintered" rotors is that sintering is a process, and the particular mix of neodymium and rare-earth materials undergoing the process can be different.

For example the materials used in Novak's original sintered rotors differ from the "exotic" recipe used in the new 13mm tuning rotor. This improved material can withstand temps to 200 C. Often, the more exotic the materials, the higher the cost.

The rotors in the Chinese Feigao-type motors are most likely sintered, but not much is known about the quality or type of materials used in their mfg processes. This may account for some of the differences noted above.

snellemin

I have this creepy feeling that Feigao is an ODM for many bigname companies. The cans look alot like Orion, Trinity, and such.

Novak2, are you serious about the 200C temperature or did you mean F? Would I be able to use that rotor is my LRP Can for example, or are the dimensions way off?

Novak2

Feigao is the OEM for many of the new sensored clones that we have seen.

I checked with the engineers concerning the 200C rating and was told that it is how the material itself is rated. Of course, our guidance for maximum motor temperatures has not changed.

The Novak rotors are not interchangeable with the LRP, or any other sensored motors that we have tested
.

snellemin

That temp rating is good info. I'm guessing I will have to get me a novak motor now then. Will there ever be a novak motor with a detachable sensor cable?

Novak2

Not any time soon....for the detachable motor harness.

But we never say "never".....

symbios24

well i have a question that need answer in here.i have a feigao motor that the rotor`s shaft is bend and needs truing any suggestions how to do it? is there a lathe that can do the job and if yes which one will fit it?

kavvika

Feiago might be the OEM for the new Trinity brushless motor, as the can looks exactly the same as their 380C motors, but I don't think they OEM any other companies motors, such as Orions Vortex and Peaks Vantage. Correct me if I'm wrong though. I'm looking for a brushless motor and have been told to stay away from Feiago, since there are better choices. I was recommended a Peak or Orion 6.5T. But if it turns out they're manufactured under Feiago, I might have to look elsewhere...

But anyways, stick with sintered rotors for cooler running motors, especially at partial throttle. The main reason the Mamba Max CMS36 motors get much hotter, and overheat in some case, is because they use a bonded rotor.

Slo-V Flyer

Nope if you read Access' post above, he linked to the Mamba Max manual, states that they use sintered rotors in the CSM36 motors.

Even then, yeah the Mamba Max motors feel easy to spin by hand, compared to my Novak 3.5R's sintered rotor which as a good "clicky" feel to it, much like a brushed motor.

Access

When it comes to heat, there are more variables than many people realize.

The basic heat generated by the motor is based on the DC resistance of the motor, but then you also have to factor in coil saturation and motor/ESC 'match'.

Ideally the coils are high-quality, high-gauge copper wire.

The coils have some inherent inductance, but this alone doesn't generate heat (until a certain point). A coil (electromagnet) will, however, saturate at some point if you keep raising the current. As it gets closer to saturation, the additional magnetic field generated per unit current drops to practically nothing, as does the inductance.

What this means is that, running a motor with current past its inherent 'coil saturation point' or 'current rating' is diminishing returns and at some point adds no additional torque, just heat. This saturation point is different depending on the KV of the motor (higher KV motor has a higher saturation point) but the torque generated at this saturation point is constant and depends on the meteriel used, the size, etc.

So for an ideal motor-ESC match, set the 'current limit' parameter of the ESC to just below or near the current rating on the motor. If the spec on the motor mis-states the current rating, you can find this point by raising the current limit of the ESC a little bit every run and observing the rise in motor temperature. There will be an obvious spike once you get near the coil saturation point for that motor.

Now if the gauge/meteriel of the wire used to make the motor is below this current saturation point, run it at the current limit for that wire type rather than the saturation point, basically the lower of the two.

One final heat issue is that a well-designed motor will conduct the heat, carrying it to the case and appearing hot during the run. A poorly designed motor might not conduct the heat very well, and hence appear cooler during the run. But the poorly designed motor will also melt as the heat isn't dissipated as fast, heat can only be dissipated if it can be transfered to the case of the motor.