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Forum Index : Windmills : Jaycar mill - 300 - 500 W???

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domwild
Guru

Joined: 16/12/2005
Location: Australia
Posts: 873

Posted: 09:04am 11 Nov 2008

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Hi,

Claims in Jaycar flier:

300 W unit starts in 2.5 m/s wind, 300 W at 12 m/s and 500 W at 15 m/s. As the spare props cost only $69.95 for three I checked the cat. no. MG-4534 item:

Three blades with 1.5 m dia (not radius!), material ABS.

Cost of unit: $599, no mast, mounting hardware or guide wires. But contains charge controller in head and slip rings. Total weight: 17 kg.

Can one get 500 W from a 1.5 m dia prop in 15 m/s wind? I doubt it and I am too lazy to put that into the formula!

Any comments?

Cheers,

Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.

Winston Churchill

oztules

Guru

Joined: 26/07/2007
Location: Australia
Posts: 1686

Posted: 09:40am 11 Nov 2008

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With only half reasonable blades .... 15m/s will give you over 1kw at the shaft to play with at 1.5 meters diam.

........oztules

Village idiot...or... just another hack out of his depth

GWatPE

Senior Member

Joined: 01/09/2006
Location: Australia
Posts: 2127

Posted: 11:09am 11 Nov 2008

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Hi Dom,

for most places where people live, 30knot wind gusts come around a couple of times a year. I know of a few places where people have built homes that 30knots is common, but the wind does become tiring. Above 20knots, loose tin on a roof starts to play tunes. The rating of a windmill to 15m/s is usually just to inflate the numbers, and only indicates late furling to me. This is probably why they throw blades and bearings. I have a 300W chinese controller on my F&P mill that seems to handle the 600W. The electrical brake does make some noise until the mill stops. 700W has been recorded from a 300W chinese windmill into a 24V battery. The guy said that the machine got a little busy at that power level, was very noisy as well, swish-swish.

I think that with a better set of blades, and some attention to bearings and weather seals, and lightening of the tail, that the chinese units could be OK.

Gordon.

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