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Evening chaps
Pete W.:
Hi there, Rob,
Welcome back. How are you?
--- Quote from: philf on February 07, 2015, 04:39:47 AM ---
SNIP
I too am too easily distracted and spend too much time looking after our hydro-electric scheme rather than getting on with jobs at home.
SNIP
Phil.
--- End quote ---
Phil, that sounds interesting, have you posted anything on it? If not, please do! :worthless:
Pete.:
Welcome back Rob. Where you been this past year?
philf:
--- Quote from: Pete W. on February 07, 2015, 09:41:35 AM ---
--- Quote ---
I too am too easily distracted and spend too much time looking after our hydro-electric scheme rather than getting on with jobs at home.
Phil.
--- End quote ---
Phil, that sounds interesting, have you posted anything on it? If not, please do!
--- End quote ---
Pete,
I've mentioned our hydro scheme once but have never posted photos or any great detail. For starters have a look at our website: http://www.stockport-hydro.co.uk/
Basically we have a twin Archimedes screw system on the River Goyt near Marple in Cheshire. (If I were being pedantic it's actually in Greater Manchester but historically we were in Cheshire.)
The weir was built in the 19th Century for a mill which was never built. There isn't a huge drop on the weir (typically about 1.2m( but it's very wide and so to maximise output we have two screws running side by side. The EA have specified a minimum level of water over the weir of 6cm. We can take as much water from the river as we like providing we maintain the 6cm level.
The 2 screws can run independently - when the river is very low we run only one screw as it's more efficient.
Unlike most of the early systems ours is a variable speed system meaning that, even when the screws are running very slowly, we can output energy to the grid. The fixed speed systems are often not running in low water conditions because they take too much water to achieve 50hz output to the grid.
Each screw has it's own sluice gate which isn't a control - they're either open or closed.
Each screw is supported at the top by, we believe, a large spherical roller bearing which is capable of taking axial and radial loads. The bottom bearing is a plain bearing which always runs under water. It's fed with biodegradable grease via a pump. The screw is connected to a 90:1 gearbox which in turn drives a three phase permanent magnet motor/generator. (Of the type used as e.g. spindle motors on large machine tools. The motors are rated at 55KW each.)
The motor/generator is driven by an inverter. The inverter is controlled by a Siemens Sinamics module and a PLC. Depending on the river level the inverter drives the motor at a speed (up to a preset maximum) to try to achieve a 6cm weir level. This speed is much slower than the screw would run if it were just allowed to run free with no load. To hold the speed the inverter is constantly braking the screw to slow it to the required speed and it's the braking that generates power. The inverter input is 600v DC and the power generated from the braking is output into the 600v bus.
A third 'grid-facing' inverter is also connected to the 600v dc bus and this inverter converts the 600v dc into 415v three phase 50hz in sync with the grid which we feed into a transformer on a power pole and then into the grid at 11kv.
We can monitor the control and security cctv cameras from home via the web.
In late November we had a major problem with one screw and have not been able to run it. We need to be able to get at the bottom of the screw which is submerged. When the system was built they were running out of money and omitted fitting some steel channels in the tail races where we could fit stop planks which would isolate us from the river and, after pumping out the water, would give us access to the bottom of the screw. It's now going to be more difficult to fit these channels than it would have been when there was a coffer dam in place. I've drawn up the channels and they're now on order. The fitting of them is going to be fun because we'll have to get some fixings in above water level, fit the stop planks, pump out some water to reveal the next set of fixings (which are then only on one side of the channel) etc. etc.
I don't want to go into any detail about how it failed because we are expecting a battle with with the screw manufacturers and the civils contractor on who's responsible for the problem. With a bit of jiggery pokery (wooden props anda sledge hammer) we managed to get the screw running again a few days ago. With the screw not running for 2 months a huge amount of silt had built up which would have hindered the fitting of the channels and stop planks. Running it slowly should clear the silt.
That's all for now - my tea is on the table.
Cheers.
Phil.
awemawson:
Phil that's fascinating - I'd like to read more but the various bits of the web site pointing to FAQ's ,Galley, Progress, Invest, News. History etc don't seem to work :(
vtsteam:
--- Quote from: RobWilson on February 07, 2015, 04:17:20 AM ---
--- Quote from: vtsteam on February 06, 2015, 06:00:01 PM ---You've got exactly 7 days to make an engine out of old pipe, pipe fittings, nails and a bolt :poke: :poke: :lol:
:wave: :wave: :wave: :wave: :wave: :wave: :wave: :wave: :wave:
--- End quote ---
Hi Steve , now thats a challenge :bugeye: are you building one ?
--- End quote ---
Almost done, Rob, and RussellT finished his innovative oscillator, Dwayne is the dark horse, still, I suspect some secret developments, there...:
http://madmodder.net/index.php/topic,10261.0.html
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