TheBackShed.com

Forum Index : Windmills : gearing VAWT & AC grid tie?

Page 2 of 2

Author

Message

goldhunter_2

Regular Member

Joined: 10/03/2010
Location: United States
Posts: 57

Posted: 08:11am 09 Apr 2013

Copy link to clipboard

Print this post

your not taking it over your answers are helpful to me

govertical
Guru

Joined: 11/12/2008
Location: United States
Posts: 383

Posted: 09:52am 09 Apr 2013

Copy link to clipboard

Print this post

Hi, thanks. I am currently fabricating new blades. I am using the same fabrication method. It will be a two part system. Because of the way I fabricate the gear drive I am able to attach a set of blades at the input and output of the gear drive. I am thinking it will help remove some of the load the gear drive places on the system. A big set of blades at the gear drive input and a smaller set of blades at the output that spin 3 times faster then the larger blades. It is just a experiment and I will post results when availible. There is good info at windgen.org , it is a VAWT forum.

just because your a GURU or forum administer does not mean your always correct :)

Warpspeed
Guru

Joined: 09/08/2007
Location: Australia
Posts: 4406

Posted: 11:37am 09 Apr 2013

Copy link to clipboard

Print this post

A BEAUTIFUL set of very efficient looking gears.
These are gears to lust over.

Much better to use two stages of relatively large gears of low ratio than trying to make one very large gear drive one very small diameter pinion.

Geovertical, you are da MAN!Edited by Warpspeed 2013-04-10

Cheers, �Tony.

Bryan1

Guru

Joined: 22/02/2006
Location: Australia
Posts: 1395

Posted: 12:09am 10 Apr 2013

Copy link to clipboard

Print this post

Hello Tony,
Earlier in this thread you stated that Delta WASN'T the way to go with wind generators. Now I've just rewound that 4kw motor and off the one wire test 1 Delta did show the best output out of the 4 configurations. As this was my first motor rewind I drew up a drawing showing the 36 poles and the coil groups which did show equal spacing with the same number of turns for each coil group so why would going 1 Delta be bad on this setup????

Regards Bryan

P.S. Sorry if this seems to derail the thread and noways am I having a dig at you but that post by you have brought up some questions.

Warpspeed
Guru

Joined: 09/08/2007
Location: Australia
Posts: 4406

Posted: 11:26am 10 Apr 2013

Copy link to clipboard

Print this post

Don't wish to derail the thread, but basically delta connection only works well with resistive loads and sinusoidal load currents.
With rectifier loads the currents in the alternator windings will be pulsing square waves, very rich in odd harmonics.

This non linear current distorts the voltage waveform, as only two out of the three windings are carrying current at any instant when driving a three phase rectifier.

You cannot connect up three windings in delta that have different or distorted voltage waveforms, just as you cannot parallel up three batteries of different voltages.
Doing so would create very high circulating currents if the source impedance is low.

This voltage waveform distortion is of no concern with star connection, but when you close up a delta connection the resulting harmonic distortion will create circulating currents around the delta loop.

Both alternators and three phase transformers that directly drive rectifiers, always have the secondary windings connected in star to avoid this problem.
Sure it will work, but it can never work as well or as efficiently as doing it properly.

Cheers, �Tony.

Page 2 of 2

Print this page

To reply to this topic, you need to log in.