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guydewdney
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« Reply #60 on: August 25, 2009, 08:39:35 PM » |
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pic of the layshaft
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guydewdney
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« Reply #61 on: August 25, 2009, 08:41:31 PM » |
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driven side.
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knighty
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« Reply #62 on: August 25, 2009, 08:45:44 PM » |
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I'm glad to see things are starting to work out for you
it must have been very frustrating... so much power there ready for your taking.... but just out of reach !
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guydewdney
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« Reply #63 on: August 25, 2009, 09:19:44 PM » |
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Utterly - theres not many water wheels about - so theres not much 'kit' for them. The vagaries of my wheel are interesting to say the least. I cannot overspeed the wheel, so I would like some sort of 'brake'. I'm dealing with MASSIVE torque possibilities - 12 ton metres anyone? and huge masses spinning round.... So all the kit has to be adjusted and made to work with what I have. Then theres the control of it....
But I reckon, if this is runnign at somthing like 20% efficient - yet is making 150-odd volts and 1.3kw - which means the inverter isnt happy (it wants 300 odd volts) - then with this amount of water, I should be able to make 5-odd kw @ 80% efficient for the genny, and be up to 90% on the inverter.
And the sluice gate is only open 12 turns (on an acro jack) - it has another foot+ or so to open! (12 turns = about 10")
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knighty
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« Reply #64 on: August 25, 2009, 09:47:12 PM » |
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so what's the plan ?
I saw your post in the other thread about the relay thingie to sync it into the grid with an induction motor...
(or to engage it with the grid when it's in sync I should day)
how are you going to sync it in ? manually ? by opening / closing the sluice gate ?
(I'm very interested because I see this as a good way (and much cheaper way) to connect in a generator)
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guydewdney
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« Reply #65 on: August 25, 2009, 09:59:35 PM » |
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nope - gave up with that idea a long time ago. opening a sluice gate takes tens of seconds to get the wheel turning, and then it is a very uncontrollable speed for a minute or so.
Now running a DC generator (just about to be changed to a permanent magnet generator) which feeds a grid tie inverter. Seems to work well. The GTI does all the syncing for me.
the genny I have right now is a 50Hp (37kw) DC motor, rated at 1100rpm, and 500 volts. Its being run at 150 volts, and 600rpm - which means its running very very gently. What I didnt appreciate, is that DC motors, below 20% or so of the rated CURRENT that they draw (or make) are horribly inefficient. I'm pulling 10 amps (the inverter max) - and at 20 amps+ the efficiency goes from 20% to 80%. This motor is for sale to anyone who wants a big generator at a slow speed....
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knighty
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« Reply #66 on: August 25, 2009, 10:08:12 PM » |
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oops, sorry i was reading an old post !
DTI is definitely the easiest way.... only problem for me is I'm hoping to run at about 30kw on each phase....
30kw is the max really... planning to control genny power automatically depending on the hot water tank tempriture.... so we only run it as hard as we need how water... if you know what i mean ? (we use a hell of a lot of hot water!)
I might be pushing my luck with 30kw per phase... that'll be getting close to the max rating for the line into my facotry... but I'll start at 6kw for G38 and then see what they say !
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dhaslam
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« Reply #67 on: August 25, 2009, 10:35:46 PM » |
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With the new generator it might still be a good idea to regulate the flow a bit by raising or lowering the sluice to keep production near the optimum. I am interested in seeing how you get on the the Chinese PM generator. Are you importing direct from China? I am still in the planning process for a vertical wind turbine which will be similar to the waterwheel in diameter and run even slower. One of the important criteria for wind is to have low starting torque and for this reason I would undersize the generator and control the maximum speed mechanically. By the sound of it the water wheel needs the opposite in order to slow it down initially.
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guydewdney
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« Reply #68 on: August 26, 2009, 07:31:16 AM » |
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Oddly - the starting torque is not as simple as that.
when the sluice is first opened, it fills the 12 o'clock bucket full, then it spills over to the 11.30 bucket, then the 11 bucket, until there is sufficient offset filled buckets full to overcome the various resistances in the drive. Then the wheel starts to turn. BUT - now the 12 bucket is at 9 o'clock - and thus generates maximum torque, so it speeds up very rapidly. The faster the wheel turns, the less water enters each bucket (less time 'under the tap' so to speak) - so torque drops off rapidly, so it slows down, so the buckets fill more.....
In practice, it cycles for a few revolutions, then settles down.
The GTI takes a few seconds to boot up - and it only starts doing this when it sees a significant voltage (50v) from the generator - so the initial startup is uncontrolled (electrically) - so I usually start it with 6 turns on the sluice (500w worth ish) and get the system settled, then give it some more welly.
I have three sluice gates. #1 is at the head of the weir - currently fully open. #2 is just after an overflow spillway/weir 50 yards further on - this is the one I control by 6/12 turns - next to this is the drain off sluice to empty the leat. #3 is the one in the launder (in my avatar - the box over the wheel) bigger pic attached. But as things have altered over the years, if I close #3 completely, then the leat fills, and overflows into the garden! Not funny. I use #3 as an emergency /temporary stop, then wander up to #2 close it, and open the drain sluice for longer stops.
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StBarnabas
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« Reply #69 on: August 26, 2009, 03:52:46 PM » |
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Guy
congrats. I became a SSEG also today but expect a paltry 4kWh. The great thing about your water system is the 24/7 nature so about 30kWh every day. I very briefly was producing 2.81kW for a very brief moment when the sun came out.
Sean
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 Gestis Censere. 40x47mm DHW with TDC3. 3kW ASHP, 9kW GSHP, 3kW Navitron PV with Platinum 3100S GTI, 6.5kW WBS, 5 chickens. FMY 2009. |
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guydewdney
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« Reply #70 on: September 26, 2009, 06:36:03 PM » |
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just some pics of a repair I had to do a while ago:-
The end of the shaft as foubnd the day we bought the place:-
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guydewdney
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« Reply #71 on: September 26, 2009, 06:37:41 PM » |
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cleaned it up a bit - and made a water wheel lifting doohicky from two bottle jacks (2 tons each - and they JUST lift it)
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guydewdney
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« Reply #72 on: September 26, 2009, 06:40:48 PM » |
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The replacement to the bronze bearing did this to the shaft when it siezed... Note new mounting bolts glued into the rock (3 foot cube rock...)
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desperate
Guest
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« Reply #73 on: September 26, 2009, 07:34:22 PM » |
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Ouch
Am I looking at the remains of something that melted!!!!!
Desperate
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guydewdney
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« Reply #74 on: September 26, 2009, 08:36:35 PM » |
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so I made a sleeve - well - got a sleeve made - cost me several hundred quid. Its precision cut on the outside to be a slide fit into the new bearing. The inside is more complex. Theres a small shoulder at the 'wheel' end which locates on the shaft at a biyt where it wasnt knackered. The clever bit is the other end. Theres a bolt, with a point on the end which I could wind in to locate the other end onto the original manufacturing end point.
Then, there is a threaded hole, which is the right size for a grease gun - I filled a grease gun (a brand new one...) with belzona's goo, and pumped it into the sleeve, filling all the gaps. There are 4 tiny holes drilled at the opposite end to let the air out, and to indicate when it was filled.
(no - it didnt melt - it got mushed by a siezed bearing running for days with 38,000 ft lbs of torque, it doesnt get stopped by anything as poxy as a bearing)
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