i might give a neu a try someday. but for now im a lehner guy, ill stick with my 1950.

Nope, a 4 pole neu (in about the same size of rotor/stator) would have got a higher torque than a 2 pole motor

1 pole more can be powered at the same time (with a little timeshift ofcourse)

Thanks for the clarification Serum. That was my understanding also.

You theoretically need half the amount turns PER pole in the same size rotor/stator/amount of copper. For the same switching frequency (commutating) you would have half the speed, twice the torque, same power... it's quite simple really.

There are several other motor types to try and counter certain motor effects... namely back EMF, inductance, magnetic resistance, etc. All effects which affect different motor types than others, each motor type being suited better for certain applications. Not that you have much choice in RC... :024:

So you now know that a 4 pole has got more torque than a 2 pole. You see, you learn every day..

Twice the torque? not entirely. You have got about the same amount of magnetic material, which can produce a maximum amount of torque, so a 4 pole won't have got twice the torque of a 2 pole. (it would be nice though)

The EMF is used to locate the rotors position. This EMF is produced (and needs to be high enough) while the motor is spinning at a certain RPM, which makes the signal high enough to make the controller decide where the rotor is located.

Most controllers start with a fixed RPM and expect the motor to follow, from there the EMF is used as a steering signal.

You forgot an important thing in you notings which makes a huge difference for motors.; internal resistance of the stator.

Not entirely true, just look at the rotor of a Neu.


Well put! A good indicator for the quality of a motor, too.

The neu accually may have less by the looks of it.

I only took the bigmaxximum and the 6 poler inrunner apart i have got.

What is the catch with the Neu rotor daf?

You don't have to take the Neu apart to see the rotor. Through the holes on the motor you can see how the "core" of the rotor is not actual magnet. You have those 4 magnets attached to this core.
As opposed to a 2-poler, where the magnet is a solid cylinder (well, minus the hole for the shaft, f'course)

Don't know what this means for our torque-discussion, though. Just an observation.

The only way would be a direct dyno comparison. Same KV Neu versus same KV Lehner (similar size/weight, too)

Yeah, that would be honest. But normally a 4 pole has got more torque than a 2 pole. the magnets are sitting where they have got the largest impact on the torque number.. As far away from the center as possible..

True

Makes sense to me.

Does it matter how much of the core is magnetic as long as the amount of magnetic flux is the same??

I would think that as long as the measured magnetic field strength is the same the mass would not matter. Frequently more mass = greater field strength however.

Generally yes, more mass=more field strength, IF the magnetic material was the same. IIRC, the Neu has a bigger rotor correct? If so, I would think the added leverage of a larger diameter rotor will offset the lack of a solid magnet - sorta like gearing down.