Vintage Jacobs Wind turbine

[Peter Klaassen]

I have been looking at wind turbine designs for a couple of months now and have recently read an interview from the 70's with Marcellus Jacobs. It seems he spent 5-10 years perfecting his turbine and had all the bugs worked out. Is the fixed pitch turbine a more reliable machine? The Jacob's article claims 25 year old turbine are still making power. I guess it all depends how much power you want to make. I haven't yet found a good picture of his blade pitching mechanism. I am interested in putting a turbine like this together. As many others have observed a wind generator has various components which are each compromised to work with each other. Is it possible for a backyard tinkerer to make something that will last and make 2.5 to 3 Kw?
Pete Klaasen
Consecon ON

[Rob Beckers]

Hi Peter,

A few years ago there were plenty of pictures floating around the Internet of Jacobs hubs, but somehow it seems they've all disappeared. Here is a picture I scanned from Paul Gipe's book (click it for a larger version).

722

This is a later model Jacobs turbine. The originals were not as 'slick' in their mechanical execution and would make a better illustration. What this shows are the blades, mounted on rods that can slide in/out of the hub, and rotate, freely. The springs hold the blades pushed 'in' to the hub (if memory serves me the original Jacobs had a single spring per blade). As RPM of the blades increases, their centrifugal force will pull them outward, until the spring force is reached and they will actually start sliding out of hub. At the edge of the blade is a ball-joint, connected to a plate. The plate simply floats with respect to the hub axis, it can rotate freely.

As the blades move outward at higher RPMs, the ball-joint will be pulled closer to the blade-axis. Since the distance of the hub-axis to the joint is fixed it can only do this by rotating the blade (towards stall angle).

The plate with those ball-joints serves two functions: First, it causes the blades to change pitch as they move in/out. Second, it 'synchronizes' the three blades so they all move the exact same amount, so the rotor stays balanced.

Hopefully this helps explain how things work. As mentioned, if you find a picture of an original Jacobs take a close look at it. The mechanism in there is made a bit more crudely and it is easier to see how it works (or how to make your own).

Keep us posted!

-RoB-

[Steven Fahey]

Peter,

The learning curve for the backyard tinkerer is steep and multidisciplinary. I started out working with fixed blades and I'm glad I did. The steps required to get pitch-control working involve a lot of trail and error. I made plenty of mistakes on my first turbines! I am in a better position to make pitch-controlled blades if I tried it now, with a couple of fixed-pitch machines under my belt. I'm keen to try, and taking my time learning it before diving in.

I guess what I'm saying is: a simple working turbine makes power. A complex turbine will make power... whenever you get it finished.

[Jim Erdman]

Some years back (maybe in the early 1980s) someone was publishing plans for the later Allied-style Jacobs governor, and also selling castings and parts. There were also a few people selling complete governors and blades to replace the earlier fly-ball style governors. I put one of the new sets on my 1940s vintage Jacobs back in 1999 or so, after using the machine since around 1977 with the original blades. It still is working fine, although I may need to replace the brushes after over 30 years of use. Otherwise maintenance is limited to checking bolts and connections, touching up paint, and semi-annual greasing of a few fittings on the tower top turntable and the governor.

I think that the best place to start for a homebuilt machine is the Otherpower.com website.
Forgot to add:
One of the patents for the Jacobs blade controlled governor (sometimes called the Allied style because it was first used on the Allied brand wind generators) is 2505969 and can be found on Google patents or the US patent site. http://www.google.com/patents?id=JCZhAAAAEBAJ&printsec=drawing&zoom=4#v=onepage&q=&f=false

Jim

[Stewart Corman]

Peter,
check out this link:
http://www.anotherpower.com/gallery/Variable-Pitch

note: there is a difference between variable pitch which is dynamic vs WS,
and varible pitch as a "lockout" to feather as a means to furl or otherwise limit overspeed.
I believe that the Jacobs is the latter design ie a governor.

I have determined that to accomodate 3KW in 20mph wind max operating point (furl),
an 18ft diameter turbine at 250rpm max is a design point ...this is not much different than the results from Dave B out in Buffalo who tested a 17 footer and then a modification to a 16 footer. Those GOE222 blades available from his buddy at Royal
are the most cost effective way to get going with a fixed blade rotor. Remember the KISS philosophy ..too many moving mechanical parts in a rough environment are a recipe for a failure mode.

Stew Corman from sunny Endicott

[Peter Klaassen]

The internet provides us all with easily accessible info. Your links are appreciated. While I am interested in home made power, I am leaning towards a commercially made wind generator in part because of the risk to the rest of my power system. Is there a possibility of damage to Outback inverters and a battery bank if one connects a home made wind generator to them? Would a home made generator connected by a commercial controller be isolated by that controller? I suppose this whole project is dependent on how much time I can devote to it; we are currently trying to finish our strawbale house.
Jim, do you have a tip down tower? Semi annual greasing means going up the tower regularly? This is a consideration as one gets older and less agile. I expect this system to last into my retirement.
I am thinking in the short term of putting up a weather station to measure the wind for a year. Down the road from us a wind tower has been put up to measure the wind for a wind farm. Thanks for the responses.
P. Klaassen

[Jim Erdman]

Any source of electricity of the proper voltage fed into your battery bank should be okay, and be no problem to your inverter, as long as the battery bank is of adequate size. Our 32 volt Jacobs is currentlly being used to charge a 24 volt battery running a Trace 24 volt inverter, and the generator is capable of putting out 60volts or so if used with a higher voltage battery, but the battery helps control the voltage. As long as the machine is designed and built for the voltage of the battery there should be no problem.

Our Jacobs is on an older windmill-style tower, and I climb it a few times a year. I am only 60 and see no problem climbing a tower in the years to come. But, I have been doing it for 30+ years, to maintain our machine. It only takes a few minutes, no one cares if you stop and rest half-way up, and I wear a proper climbing safety harness with appropriate lanyards. A tilt-down tower could be nice, but for a heavier generator like mine, it would have to be quite a bit heavier than many of the tilt-down towers I have seen. Also, a tilt-down tower takes up a lot of room with the guy wires and the space to tilt it down. And I have seen a few tilt-down towers that failed or collapsed when being tilted for maintenance. It can be a very touch process! So, I prefer a regular self-supporting freestanding tower with climbing steps built into it.

Jim