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Forum Index : Windmills : To re-wire or not re-wire

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Smokey5159

Newbie

Joined: 28/06/2011
Location: Australia
Posts: 11

Posted: 12:38am 02 Jul 2011

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Hi,
Can anyone tell me why you can't just rectify and reduce the standard F&P motor output from factory standard - rather than rewiring it?
There may good reasons, but an electrician friend of mine posed this question.
Cheers.

Air Bender
Senior Member

Joined: 25/01/2011
Location: Australia
Posts: 206

Posted: 07:49am 02 Jul 2011

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Hi Smokey5159

Im not realy up there with the electrical side of things but from what I can work out, when you rewire you are not reducing the output you are just changing it by reducing the volts and increasing the amps, and i think if you do it any other way there will be loses in the general output.

All the best Dean.

Rastus

Guru

Joined: 29/10/2010
Location: Australia
Posts: 301

Posted: 07:45pm 02 Jul 2011

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Hi smokey 5159,
Electricians are trained to work with high voltages and are aware of safe working practices.A standard wired F&P, will have a wild output up to several hundred volts and is not at a convenient or safe level.The forum provideds rewire details for 48v and lower systems.While there still are risks,they are generally at a level that aren't life threatening.The balance of equiptment to complete a working system are readily available and cost effective,however any grid tied system should be certified by a qualified electrician/inspector.An electrician who is already a friend will be able to guide you through a F&P mill build and can have any of his questions answered in the forum by other tradesmen/proffessionals.I am in the same club as Dean,I don't understand everything,although I should know a lot more,but didn't take full advantage of learning from my dad, who was a proffessional Mechanical and Electrical engineer.Some things just don't work out to plan.If I've lead you in the wrong direction,others will help set it straight.Cheers Rastus

see Rastus graduate advise generously

Gizmo

Admin Group

Joined: 05/06/2004
Location: Australia
Posts: 5078

Posted: 11:10pm 02 Jul 2011

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Yeah the guys are right. Its to decrease the voltage, increase the amps, and make the thing safe and easy to use. One of the most common modifications is the 7X2C, where the output voltage is divided by 7, and the amps multiplied by 7. So a alternator that makes between 170 and 200 volts at 2 amps in the wild, is tamed down to 24 to 28 volts at 14 amps, perfect for chariging a 24volt battery bank.

It is possible to use the stator in standard trim, and use transformers or switchmode power supplies to reduce the voltage, but its much more complicated, and you can end up with a dangerous situation if you get a overspeeding run away windmill generating several hunred volts.

Glenn

The best time to plant a tree was twenty years ago, the second best time is right now.
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