The Jacobs boys built two distinct different families of turbines over the years. The DC models like the Jake Model 25 were built from the early 30's to the late 50's. The grid-tie models (23-10, etc.) were built from the early 70's thru today (now owned by Wind Turbine Industries Corp, or WTIC, in Prior Lake, Minnesota:
http://www.windturbine.net/They have all earned a reputation of surviving conditions no other turbine will survive in. The grid tie units are also VERY expensive. You're looking at $70,000 for a 31-20 on a 120 foot Rohn SSV tower, and usually another $30,000 for installation. They require a crane on-site, they require major excavation and concrete in the tower base, and they require people installing them that know what they're doing. They are far beyond what the average DIY'er can install and get running.
Bergey Wind Power surpassed Jacobs for sales in the grid tie business with their Excel 10 turbine because it's way cheaper than a Jake. Bergey came on the scene in about 1985. Mike Bergey more targeted the residential market instead of the farm and ranch market:
http://bergey.com/So today Bergey installs Excel turbines for smaller systems. Jacobs still installs a few for those who can afford them. There's literally hundreds of Jacobs grid-tie turbines that have been running for 40 years all across the upper Midwest. There's better than a dozen of them within a 80 mile circle from our place.
The guys who service Jacobs turbines (there's only a couple left) are grizzled veterans who will climb a 120 foot tower in 40 mph winds at 30 below in North Dakota to grease the turntable on a 31-20 with the turbine running flat out. And they still do things like lower and raise a 120 foot Rohn with a 3,600 lb turbine on it using a 20 ton deadman buried in the ground to anchor the service truck to, put a 40 foot gin on the tower and use a 30,000 lb hydraulic winch to winch it up and down.
The guys who service Bergey turbines are mostly a new breed that are not equipped to handle the massive amounts of iron in a Jacobs turbine. One of the Jacobs guys that's left around here, just to show how nothing phases a man that services Jacobs turbines, had a service truck that got wore out over the years so he bought a new one. He welded a framework under that old truck and mounted it on a 120 foot Rohn tower with a crane on a Jacobs 31-20 turntable. He put a tail on it and the whole nine yards and it turns like a weathervane in the wind up on there on that tower. That's the kind of guys that work on Jacobs turbines. They ain't afraid of iron and there is no such thing as plastic and aluminum in their world.
Bergey Wind Power once stated right on their website:
Wind turbines can run up to 7,500 hours per year and during storms they must endure tremendous forces. The history of the industry dating back to the 1920's clearly shows that lightweight turbines do not stand the test of time. The heavy duty Jacobs turbines from the 1930's can still be found running today. Their lightweight competitors are long goneSo basically, even the new guy on the block does not ignore the lessons in wind power that the Jacobs boys learned and taught us on how to build a wind turbine that will survive. Steve Jacobs, Marcellus' grandson, is on this forum. He checks in here every now and then - the last I heard he was searching for an old DC model to restore.
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Chris