Hello,

I'm an electrical engineer. I have studied motors(dc brushed as well as brushless). None of the motors I have come across have such high P/W ratios. Speed I agree can be achieved. But I dont understand how a puny 500gm-600gm motor can withstand 1kW-1.5kW. Any explanations would be welcome. I live in Pune. So if any of you are in my city I'd really love to meet you guys....
Thanks in advance.....

because they are outrunners where coil is steady and outher shell spins and that's the reason these motors produce more torque compare to any dc brushed or inrunner brushless.

These are not DC but actually 3-Phase motors. And the power rating are not RMS value I believe.

You know, every machine is limited by the thermal limit so that it wont burn. So, if cooling is better, the machine can be run with increased load. Now comes to some technical issue. Here, the motor is running with very high power/weight ratio for various reasons, but the efficiency is poor than other motors as here power output with less weight is the criteria rather than efficiency of individual motor efficiency.

Now, the design detail.
1. As, no brush commutator mechanism is here, you can get higher current with much less voltage drop (Switching through MOS of ESC where voltage drop is very much less than commutator arrangement).
2. The flux density is very high due to use of Neo Magnets.
3. As synchronous motor with lower inertia, we can use it simply.
4. Overall system high efficiency demands lower weight rather than lower loss in normal application

Hope, I can explain as simple as I can.
Neodymium is a rare earth material found in mostly Tibet and that is why china is the main exporter of Neo Magnets.

yes magnets and three phase is the biggest reason ....

Thanks guys for the info. So basically, they're cooled better... is that it?