Quote:
Originally Posted by nuz69
Coreyfro, it's just some suppositions but here is my opinion :
When you put a 4 poles rotor instead a 2 poles, you divide the Kv by 2, but the Kt (torque coefficient) rise by 2, that mean for the same amp draw, you have twice the torque you would have with the 2 poles and as the RPM drops too there is less magnetic losses in the stator. So the 4 poles motor would be more efficient and would handle more power if it has to, or will consume less power for the same performance
Obviously the stator of a 4 poles motor is designed differently than a 2 pole motor (more slots) but here is the idea...
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There are other things that come into play as well, such as rotor diameter (which increases torque by the square of the diameter) stator length (linear torque increase with stator length) air gap (decreased torque by the cube of the air gap) etc...
What we've tried to do is make the most efficient possible motor -- while making it as efficient as possible over the entire usable range.
This means increasing the torque per turn as much as possible, while minimizing no-load current. The 1406 motors are all 1-turn motors, with small tweaks in other areas to change the Kv (mostly by changing the stator length...)
So the motor that makes the most power is the 1409 SCT motor, with it's very long stator and rotor. As the Kv of these motors goes up, the maximum continuous power goes down... but high Kv motors are usually used in fast, lightweight cars, so the power requirements are lower.
Burst power from these motors is incredible... the 50% efficiency point (the point where more input power won't generate any more output power, just more heat -- those of you who run ROAR motors know what I'm talking about) is so far down the graph that we can't hit it without destroying the motors. So they can be used in high burst applications (like drag racing) just as well as oval, dirt track, etc...
These motors use .2mm powder coated laminations (expensive -- but much lower no load current -- almost all other motors on the market use less expensive .35mm laminations) oversized NMB bearings, high temperature magnets (N38UH -- good to 180C temperatures) 180C rated windings, 6061-T6 case components, etc...
These motors were designed to be as bulletproof as possible, and as efficient as possible.