Neu motor rpm speed question for BrianG

Originally Posted by BrianG

Define "better".

If better means "more efficient"; to me it doesn't matter if temps during my informal testing are any guide.

If better means "smoother"; then yes. I daresay almost as smooth as a sensored setup at low speed. Smoother running would also lessen the chance of cogging at really low speeds - and we know that a cogging (effectively stalled) motor pulls LOTS of current.

You don't want to go crazy with this idea though, like putting a 1527/1d (kv=2300) on 6s lipo on a 8th scale buggy, but gear down for 20mph. The motor wouldn't be loaded enough.

What I am trying to say is that I don't like getting a low wind and applying low voltage for low rpm and then gearing up to compensate for lack of speed.

So which would be more efficient?

1515 with lower kv and lower voltage but geared up vs
1512 with higher kv and higher voltage but lower gearing

assuming they are speced to run the same speed. It sounds like you are saying that a 1515 with more torque would be better suited for lower kv/high voltage setups vs the 1512 which might be better at higher RPMs. Since the 1515 is a stronger motor, it would seem the lower kv setup wouldn't have the cogging issues you are referring to...

[VintageMA]

I think we are getting a little bit away from my original point. I don't think there is a question here about LV compared with HV. It's a proven point by Ohm's law that if voltage goes up across any resistive load then current goes down (it is the resistive part of the motor which generates the heat - aside from the spinning bearings which do generate some mechanical heat).

I've easily proven to myself that running a 6S setup is much cooler than running a 4S setup due to amps pulled.

You can't really make a comparison between a 1512 and a 1515 at different kvs - the 1515 is bigger and will draw more amps.

The question is more about that happy point where you get the most efficiency out of the motor. Compare a 1515 2.5D (1650kv) and a 1515 1Y (2200kv) both running at 6S. That 36600rpm vs. 48800 rpm say geared for the same speed - which would run better.

With the Faiegos and other cheaper motors you couldn't run over 35K without major heat issues. So that is where I have been shooting for even when buying Neus. Now I am more curious what happens when you aim your peak rpms to be closer to 50k.

Both motors will have gobs of torque and the question of efficiency comes into play asking the question - which will draw more power and produces more heat:
- The slower motor with a bigger pinion, or
- the faster motor with a smaller pinion

When do you hit the point that the motor is spinning so fast with too small a pinion that it isn't loaded enough, or conversely when do you hit the point that the pinion is too large and you are over loading the motor.