KDE Brushless Outrunner, 5.5KW continuous 12KW Peak

magudaman

magudaman

10 kW
Joined
Jul 10, 2007
Messages
695
Location
Bay Area, CA
Came across this guy in a RC helicopter magazine and thought it was pretty impressive:

700XF-395 HP BRUSHLESS MOTOR

kde700xf395hrrendering.jpg


Key Specifications:

Kv: 395 rpm/V
Maximum Power : 12,000+ W
Continuous Power: 5,500+ W
Maximum Efficiency: 92%
Optimized Voltage: 51.8 V (14S)
Voltage Range: 44.0 V (12S) - 59.2 V (16S)
Io (@10V): 1.2 A
Rm (Wind Resistance): 0.022 Ω
Magnetic Poles: 8, 12S8P
Bearings: Quad, 698ZZ/MR148ZZ
Weight: 685 grams

They are using .2mm stator laminates, hand wound (super fine copper fill), N45SH magnets that are good to 180c and don't have permanent losses till ~320c. Seems like some nice quality for the price. I would love to get one on dyno. Pair it with a P62 gearbox from neu and your set!

kdedirectxfbrushlessmot.jpg


[youtube]z0TE9KpJ-IE[/youtube]
 
kinda nuts that they expect 12kw out of something half the size of the C80-100 that we all would max out at 10kw even with modifications. I know fans would make a huge difference(20%+) but i doubt it would almost double the power output even with the higher RPM as this would be the same size as the C6470 motors people have been able to get about 6kw out of peak.

Tho saying that they are in a completely different field to the C80-100 motors with much better design, so they may just be able to perform up to specs. Not sure about the 8mm shaft tho, but its probably properly hardened so will be stronger then the 12mm in the Turnigy etc motors. Having a good fan on it will make it insane for e-bike purposes, ahhh i wana buy one now, even has free shipping international o_O No money yet :(
 
All they have done is reduce the pole count & cranked the kv up on a 45ish mm stator motor....its goint to have less tourque potentials (or efficancys)givent the angular relationship of tooth to rotation.

I wont say pure BS, but I will call it hoplessly optomistic marketing.....less useful than a 170kv 6374 IMHO
 
A bit of crude number crunching:

A 6kg 800 series model helo has an average power consumption of under 2kW (my quick and dirty figures suggest about 1800 W). Sure it'll pull peaks of several kW during 3D manoeuvres, but the average motor power will remain around 2kW.

These people can make claims like "5.5kW continuous" for their motor, secure in the knowledge that even under really hard 3D flying their motor won't pull anywhere near that continuous power, more like a half that at most. If it was able to run at 5.5kW continuously, and assuming it can run at the quoted efficiency of 92% at that power level, then it would be dissipating around 440 W of heat. Looking at those tight windings I really can't see that size of motor being able to shed that much heat, even with their very neat fan.

Having said that, it does look like a very nicely made small outrunner, certainly a lot better made than a lot of the stuff out there.
 
Awe man you guys are killing my hopes of a 1 pound and 10HP setup.

Jeremy Harris said:
A bit of crude number crunching:

A 6kg 800 series model helo has an average power consumption of under 2kW (my quick and dirty figures suggest about 1800 W). Sure it'll pull peaks of several kW during 3D manoeuvres, but the average motor power will remain around 2kW.

These people can make claims like "5.5kW continuous" for their motor, secure in the knowledge that even under really hard 3D flying their motor won't pull anywhere near that continuous power, more like a half that at most. If it was able to run at 5.5kW continuously, and assuming it can run at the quoted efficiency of 92% at that power level, then it would be dissipating around 440 W of heat. Looking at those tight windings I really can't see that size of motor being able to shed that much heat, even with their very neat fan.

Having said that, it does look like a very nicely made small outrunner, certainly a lot better made than a lot of the stuff out there.
Click to expand...

You have seen these guys fly :wink:

http://www.youtube.com/watch?v=VvWgAEeRfpg&t=2m39s

They do get number out of the castle ESC but those are all input numbers, for example on the above video 4400w input 9900 peak
 
magudaman said:
You have seen these guys fly :wink:

http://www.youtube.com/watch?v=VvWgAEeRfpg&t=2m39s

They do get number out of the castle ESC but those are all input numbers, for example on the above video 4400w input 9900 peak
Click to expand...

4400 W continuous would be the average power that a helo weighing around 13 kg would need, which is a fair bit higher than I'd expect for this size of helo. As the saying goes, what goes up must come down, so you can use masses of power to accelerate the helo upwards, but that is then balanced to some extent by the much lower power needed to accelerate it downwards.

I'm sure they pull really high peak power, but ultimately the average continuous power will be primarily a function of weight, more than anything else. I'm no expert on these things, but get the feeling that these things tend not to weigh more than around 6 or 7kg.
 
I am a heli expert (or experienced hobbyist lets say) and yep theres a few things to consider:
Elec helis typically fly for 5 minutes at a time, afterward the motors are hot (180f is common)
Avg power for 700 size heli (biggest you normally see, at 11-12 lbs rtf or 5-6 kg im guessing) is around 1-2kw
6000+ w peaks are common but of short duration
The motors are typically used at 80+% throttle settings
Heli flyers seem to be impressed with bling more than function
Heli guys would be more impressed with higher peak power than better efficiency


And yep there have been deaths but thats rather uncommon. Usually if it hits you, its a few dozen stitches, maybe loss of a limb or eye. It happens and it aint pretty. The only saving grace is that they usually fall like a brick when control is lost, quite unlike airplanes that continue their path and cover a lot of distance when out of control.
 
I don't think the specs very are over exaggerated. 400 RPM/V and 50V makes 20000 RPM. At that speed the fan will move a lot of air. At 1/3 speed, the continuous torque is probably significantly lower.

I don't see it as a potential ebike motor, since it would need a multi step reduction. The weight of motor + reduction is probably higher than a bigger motor which can drive the wheel through a simple chain reduction.
 
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