I thought this design let the front blades spin one direction (turning the rotor) and the back set of blades spin the opposite direction (turning the stator).....
1112
dem45133
Mar 3, 2008 2:29 am
No... Doug's is a little different dual rotor set up. For conventional contra rotating rotors you are right... but the downstream rotor only has about 1/3 the...
1113
ferrand
ferrandst
Mar 3, 2008 10:52 pm
Harold, The arrangement you describe [contra rotation] was first put forward by Honnef in Germany, in "Windkraftwerke" published in 1932, researched by the 3rd...
1114
David G. LeVine
dlevine144@...
Mar 3, 2008 10:54 pm
... Go to a big public library or the library at an engineering school. Ask for a research librarian and ask for the librarian's recommendation. You would be...
1115
David G. LeVine
dlevine144@...
Mar 3, 2008 10:54 pm
... A ferrous core will improve efficiency at the expense of cogging effects. If the particles are small enough, are insulated from each other, and do not...
1116
David G. LeVine
dlevine144@...
Mar 4, 2008 12:07 am
... Where did you find them for that price? The best price I found was above $50.00 when I got one. -- David G. LeVine Nashua, NH 03060...
1117
David G. LeVine
dlevine144@...
Mar 4, 2008 12:07 am
WARNING, engineer speak. ... Nope. As you get above 3 phases, the costs and weights of components starts to rise. A three phase system generally uses three...
1118
David G. LeVine
dlevine144@...
Mar 4, 2008 12:08 am
... Not really, look up a stepping motor (stepper). What they generally do is first slowly put steps into the motor, then ramp up to speed. The first step is...
1119
David G. LeVine
dlevine144@...
Mar 4, 2008 12:08 am
... Glass, aramid (like Kevlar) or carbon fiber are generally good strength members to prevent forces on a rotating structure from pulling the assembly apart....
1120
ferrand
ferrandst
Mar 4, 2008 12:08 am
The Trimblemill [see Group files] uses three blades on the front rotor for speed, and five on the back rotor for maximum power collection - following the...
1121
ferrand
ferrandst
Mar 4, 2008 1:02 pm
Mark All Tower Cranes have a small slip ring assembly at the top to transfer power from the ground supply to the crane drive motors. Used on the Trimblemill...
1122
Dan
qazxcvb21
Mar 4, 2008 1:02 pm
... rotor for speed, and five on the back rotor for maximum power collection - following the establishment of this number by John Smeaton in his modal...
1123
Brian Rodgers
outfitnmbr
Mar 4, 2008 1:16 pm
Are you asking about the electrical connection or the mechanical connection? Huh Piggot style systems use a pipe in a pipe (each capped) as a bearing. Both...
1124
Steve Spence
sspence65
Mar 4, 2008 1:18 pm
And it works so well. Because the turbine moves back and forth, you might be surprised at how little twisting actually occurs. We pivot on a set of motorcycle...
1125
jerry freedomev
freedomev
Mar 4, 2008 1:53 pm
Hi Ferrand and All, ... While counter rotating windgens are more eff if designed right, they are always more expensive and require more maintainance per unit...
1126
hiburd28
Mar 4, 2008 10:31 pm
I live in north west Ohio, ice storm today and i thought how would this generator do in this type of weather. so if anyone has any feed back i would like to...
1127
sspence@...
sspence65
Mar 4, 2008 10:33 pm
We run ours in northern NY, above Watertown. They work great in ice and snow. If painted black, the sun will melt off any icing up. ... From: "hiburd28";...
1128
Brian Rodgers
outfitnmbr
Mar 5, 2008 3:15 am
Video of a commercial wind turbine being destroyed by high winds Very cool. Brian http://www.filecabi.net/video/84815-f9b1.html -- Brian Rodgers All Internet...
1129
Laramie
ranger-o
Mar 5, 2008 3:08 pm
I saw this turbine on PBS and thought the blade design to be well thought out. But is it? www.helixwind.com...
1130
Steve Spence
sspence65
Mar 5, 2008 3:08 pm
Looks like a pipe dream. No axial flux alternator either....
1131
ferrand
ferrandst
Mar 5, 2008 4:02 pm
Jerry, For smaller WT's where a gearbox is not required clearly contra rotation will probably not compete. However for higher power ratings where gearboxes...
1132
rem3win
Mar 5, 2008 5:21 pm
looks like a basic savornius design, if you home built one could use an axialflux generator...but would have to wind it for very slow rpm...
1133
dem45133
Mar 5, 2008 6:05 pm
I checked out his page briefly... its a very small unit... engaging a very small amount of wind area... small intercept area=small or tiny E available to start...
1134
Drew Meyer
edguy4u
Mar 5, 2008 9:12 pm
memo to me.... Do NOT stand near wind turbines in a storm........ BTW, I heard the thing wind up and then a click as it fell apart. Did a rotor blade fail...
1135
jerry freedomev
freedomev
Mar 6, 2008 2:22 am
Hi All, A couple months ago I saw an article in the Tampa Tribune on a guy building windgens. I though probably another off the wall nut but since it mentioned...
1136
Brian Rodgers
outfitnmbr
Mar 6, 2008 1:23 pm
Over on Fieldlines forum they slowed the video down and noticed that one blade came apart first and hit the tower ... -- Brian Rodgers All Internet traffic...
1137
Michael Vanecek
mikevanecek
Mar 6, 2008 2:30 pm
It's kinda like tug-of-war - if one side lets go, the other side immediately falls down. All it takes is the loss of one blade to cause the whole thing to fly...
1138
dem45133
Mar 6, 2008 2:59 pm
From previous posts on another thread about this failure, its my understanding it was being, or getting ready to be, serviced... for a faulty over speed...
1139
Dan Fink
danbob88
Mar 6, 2008 3:16 pm
I live in north west Ohio, ice storm today and i thought how would this generator do in this type of weather. so if anyone has any feed back i would like to...
1140
Dan Bartmann
buckvillian
Mar 6, 2008 3:32 pm
In Colorado we rarely have ice storms. But - if the machine stops turning and you do get an ice storm (or snow that melts/freezes in the alternator) it's not...
