## Build a 5m rotor diameter

Solar, wind, hydro and other non-fossil sources of electricity.
jlcortex   1 mW

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Joined: Jan 31 2011 1:30pm
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### Build a 5m rotor diameter

I'm thinking of starting a serious project
In my opinion if you build a wind turbine you have to make it big, What do you think?

Rotor diameter = 5m
A 5m rotor can get more than 5000W but I would like to optimize for slow wind, about 6m/s, I am calculating 2500W or so.
I am thinking to build blades in wood and use a multiplied hub motor as generator.

It has sense?
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Lebowski   1 GW

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Joined: Jun 28 2011 1:38am
Location: beautiful Zurich, Switzerland

### Re: Build a 5m rotor diameter

I would go vertical, somehow seems easier for diy...

https://en.m.wikipedia.org/wiki/Vertica ... nd_turbine

jonescg   1 GW

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Location: Perth, Western Australia

### Re: Build a 5m rotor diameter

A hub motor would probably be a good match considering the low speeds. Hope to see this progress

jlcortex   1 mW

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### Re: Build a 5m rotor diameter

Captura2.PNG (342.82 KiB) Viewed 257 times
I like horizontal wind turbines. About hub motor, I see hub motors very simple, reliable and cheap. I am thinking about use a 500W 12V hub motor at 5X the nominal speed to get 2500W, it is very big motor, i think 2500W is not problem if it spin 5 times faster.

billvon   100 MW

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Location: san diego

### Re: Build a 5m rotor diameter

jlcortex wrote:
Jun 09 2019 6:25am
A 5m rotor can get more than 5000W but I would like to optimize for slow wind, about 6m/s, I am calculating 2500W or so.
I am thinking to build blades in wood and use a multiplied hub motor as generator.
A 5m diameter rotor, in 6m/s wind, is going to get 2500 watts at 100% efficiency. At more reasonable efficiencies expect 1000 watts or so. Also 6m/s is about 14mph which is a pretty strong wind. We rarely see winds above 12mph down here.
--bill von

Hillhater   100 GW

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Location: Sydney ..(Hilly part !) .. Australia/ Down under !

### Re: Build a 5m rotor diameter

jlcortex wrote:
Jun 10 2019 3:53pm
..... I am thinking about use a 500W 12V hub motor at 5X the nominal speed to get 2500W, it is very big motor, i think 2500W is not problem if it spin 5 times faster.
Why 12 volts ? ....you will be dealing with high amperage .
48 -60 v would be more practical.
Also check the efficiency of the motor at 5X normal operating speeds.
A 3kW hub at normal design speeds would seem to be more realistic and still cheap.?
This forum owes its existence to Justin of ebikes.ca

jlcortex   1 mW

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Joined: Jan 31 2011 1:30pm
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### Re: Build a 5m rotor diameter

Hillhater, I am meaning 12V hubmotor spinning at 5X the nominal speed so it will be 60V, rated current will be about 42A.
The hub motor is a huge electric motor, the power is low because the RPM is very low, but I think nothing prevents the engine from spinning much faster than it does on a bike.

this is my wind:
weatherspark.PNG (39.29 KiB) Viewed 206 times
https://weatherspark.com/y/42614/Averag ... Year-Round

this other site is a map with wind power density
https://globalwindatlas.info/

136W/m2 in my area at 50m. I am not an expert but I think the calculation should be something like that:
Average Power = Wind power density * Area * turbine efficiency * generator efficiency = 136*19,64*0,4*0,86 = 918W
My tower will not 50m so I estimate near 700w average, about 6MWh/year

jlcortex   1 mW

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Joined: Jan 31 2011 1:30pm
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### Re: Build a 5m rotor diameter

I just realized that the 12V hub motors are not very popular, but some items can be found:
https://www.alibaba.com/product-detail/ ... 78a5MKzt68

billvon   100 MW

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Joined: Sep 16 2007 9:53pm
Location: san diego

### Re: Build a 5m rotor diameter

jlcortex wrote:
Jun 11 2019 4:16pm
My tower will not 50m so I estimate near 700w average, about 6MWh/year
I get 200w average, assuming 8mph wind average.

Tower minimum height is going to be 12.5 meters plus the height of the tallest object within 200 meters of the turbine.
--bill von

Hillhater   100 GW

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Joined: Aug 03 2010 10:33pm
Location: Sydney ..(Hilly part !) .. Australia/ Down under !

### Re: Build a 5m rotor diameter

jlcortex wrote:
Jun 11 2019 5:00pm
I just realized that the 12V hub motors are not very popular, ....
That was one reason i suggested using a higher power/voltage rated motor ...
Another being the efficiency/heat build up if you use a 500W motor to regen at 5x its rating
This forum owes its existence to Justin of ebikes.ca

Punx0r   100 GW

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Joined: May 03 2012 8:16am
Location: England

### Re: Build a 5m rotor diameter

jlcortex wrote:
Jun 11 2019 4:16pm
The hub motor is a huge electric motor, the power is low because the RPM is very low, but I think nothing prevents the engine from spinning much faster than it does on a bike.
Unfortunately most hubmotors are built to spin slowly. They have high pole counts and thick laminations which mean core losses become large when the speed goes much above the nominal.

mettleramiel   10 W

Posts: 78
Joined: Dec 28 2007 10:26am

### Re: Build a 5m rotor diameter

Go to the forums on otherpower.com . They have tons of info on building your own wind turbine and even sell lots of the parts needed to do so.

5m blades is very large to start off with, though.