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Title: How can such small motors spin sooo fast and deliver so much power? Post by: PanditAero on December 27, 2011, 09:25:47 PM 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..... :) :) Title: Re: How can such small motors spin sooo fast and deliver so much power? Post by: Dharmik on December 27, 2011, 09:44:23 PM 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.
Title: Re: How can such small motors spin sooo fast and deliver so much power? Post by: ujjwaana on December 27, 2011, 10:36:53 PM These are not DC but actually 3-Phase motors. And the power rating are not RMS value I believe.
Title: Re: How can such small motors spin sooo fast and deliver so much power? Post by: KALYANPRODHAN on December 28, 2011, 12:17:25 AM 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. Title: Re: How can such small motors spin sooo fast and deliver so much power? Post by: vineet on December 28, 2011, 01:47:23 AM yes magnets and three phase is the biggest reason ....
Title: Re: How can such small motors spin sooo fast and deliver so much power? Post by: PanditAero on January 06, 2012, 04:34:52 PM Thanks guys for the info. So basically, they're cooled better... is that it?
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