Brushless Hub motor as 3 phase generator

[Gotwind Ben]

Correct Shawn..

[Gotwind Ben]

I collected the Brushless Hub motor today.
On first tests I'm most impressed.

The 24v version has a phase resistance of just 0.3 ohms suggesting there is some reasonablly thick coil wire used. (more efficient).
A hand spin would light a 50 watt bulb easily and cogging was unoticeable, there was some stiffness in turning the wheel (to be expected).
These motors really are just about perfect as wind alternators, and if they can be bought at the right price a good buy as Shawn and others have found out.
The 48v versions would also be in VAWT territory, 12v cut-in at approx 108 rpm.

With this latest figure I have found, there should be a lot more in circulation soon..
'In 2009, China's output of electric bicycles reached 22.2 million,'

Read more: http://www.earthtimes.org/articles/show ... z0kLv9JlCW

[Gotwind Ben]

Wow.
I managed to generate 300 watts via pedal power :D
That was hard going, 100 watts was sustained for 15 minutes, then I was knackered.

The hub motors are rated at 85% efficient as motors, I need to figure out a way out of measuring my physical input to calculate the efficiency as a generator, power out is the easy bit with a Watts up meter.
I suspect efficiency will be close to 70%, hard to predict.

I managed to choose the warmest day of the year so far, hence clothing removed in the background ;)



Well, 299 watts peak.

I might have to build one of these my wife really wants one :o :shock: :mrgreen:
You can bet if we ever do have a power outage the battery will be flat,there will be no wind or sun :roll:

sweeet! :)

nice job ben, curious? do these hubs bolt right in..do we need to "splay" the back fork/frame at all? and the derailer lines up as it should? tell ya i've paid a lot more than that for total junk! (several times) :cry:

sure gives one a renewed appreciation for wind and solar power after a good stretch on one of these.


cheers, dave

[Gotwind Ben]

sweeet! :)

Do these hubs bolt right in..do we need to "splay" the back fork/frame at all? and the derailer lines up as it should?

Dave.
That is a good question, my hub would not accept a multi gear freewhel (sprocket) and still fit in the 135mm gap in the rear 'dropout'. I had to use a single speed gear, 13 tooth, for my purposes that was fine.

Some hub motors will fit straight in others won't, worth checking on purchase, also my hub had a disc brake fitting on the opposite side to the freewheel.

[Gotwind Ben]

Me being me,
After a week of owning this hub motor and seeing it perform very well as a permenent magnet alternator, I want to see whats inside of it :D

This may be of use to members here owning similar units for maintenance also.
A quick Google video search provided me with a great insight.



Notice the skewed stator teeth slots to minmize cogging (Same as the Freeplay alternator).
I suspect I can borrow a hub 'puller' from someone for free.
The videos reassembly looks pretty hit or miss, but seems the safest way to go, there is no way i would try and introduce a steel cored rotor into a Neo magnet lined rotor of that size - serious finger pinching :o

Just thought I would pass on what I find on my Internet travels :D

[Gotwind Ben]

I have put a page up on the main site detailing the pedal generator project for anyone interested.
http://www.gotwind.org/diy/300w-Pedal-generator.htm

It may be of use to someone, I enjoyed it :D

[Gotwind Ben]

Wheel rim and tyre removed has decreased performance a litlle bit, 25 watts less at a guess via the 'watts up' meter (10%).
Hi res image
http://www.gotwind.org/diy/images/300w- ... ower_L.JPG
The flywheel effect of the 26" wheel, all be it of Alluminium construction has probably something to do with it.



I just want to add this image again as the haircut. (I had one similar years ago) makes me laugh :)

Hi Ben

I think that your claims to producing power are a little high.
I do a bit of pedaling and do not think that I could not do 150 watts for 30 mins.
100 watts is much more realistic for the average person, as for 300 watts, that as you stated would be a 5 secs burst.
The real point of my comment is what power would be needed to hit the 225 revs ie 12 volts, because to make a workable generator an average person must be able to do that speed on a semi=continuous basis.
I think that a lower power motor is required or a unit that requires 48 v so that the 12 v is hit at lower revs.

Dennis