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Forum Index : Windmills : Windmill Alternator Nice +SS shaft
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| kingull Regular Member  Joined: 08/04/2010 Location: AustraliaPosts: 44 |
SSW_Squall I am retired Electrical contractor and never had a defect notice on any of my installations so I dont intend to start now. This whole post got out of hand from what it started out as but it is quite interesting. I once helped Linux on news sites and was delighted to receive an email from Mandrake Linux thanking me for my help and asked if they could use my article. I was rather stunned but delighted at the same time. It is nice to see it happening here. I have ordered two PMA type units and the Turgo from a delightfully helpful Joe Hartvigsen. One is 12 V 85 Amp and the other is a 380 volt DC 3 HP motor with PM stator but wound commutator rotor. Brush life at best is around 700 hours which I expect from a Pacific Scientific unit. I am contemplating teeing off near the Hydro nozzle and dumping the water if the grid drops out. Not sure how to attack that but maybe a solenoid valve. 24 volts DC already exists at the hydro proposed location from a "Choice solar driven pump" from twin 85 watt 12V series connected panels. Michael Lawley wont stop advising me even though I decided not to use his "HE Powerspout". (Would not handle the head).Interesting Guy. Summing up: The system will likely have 240 Volt AC down to the Hydro Generator location. Now situated closer at about 80 metres from the house switchboard. Probably 10 mm2 cable. Probably Aerial. GTI also located near Hydro Generator. The mains power could be used to dump the teed off water. If I use the Pacific then DC will be transmitted to GTI at house using a Sunny Boy SMB 1200. So, all i really need to solve is dumping and opening the 235 foot head line. It is the safest way to go. Suggestions are welcome. Needs to be instant opening valve. Resetting can be manual. Just woke up: Relay operated solenoid valve Or one on Ebay seems to open if power is off. |
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Downwind Guru  Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
A large solenoid could do the job and we used to use 2" ones for irrigation use. But most of them require power to hold them open and this might be a down side. I would rather a butterfly valve with a electrical actuator if it was me. Along with the actuated valve i would install a manual valve next to it. Reason being actuated valves can open and close quickly, but a slam shut with the flow of water could rupture your line. Proceedure would be auto open of dump valve and manual close. Before you closed the actuated valve you would need to open the manual valve next to it and then close it slowly after the auto valve was shut. This will garrentee no water hammer effect to rupture your line.(total control) If need be you can mechanically link 2 valves together so the one actuator opened the dump line and closed the water jet line in one action. Pete. Sometimes it just works |
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| kingull Regular Member Joined: 08/04/2010 Location: AustraliaPosts: 44 |
http://www.toro.com.au/irrigation/view_doc.cfm?doc=18 might be just "spot on" Solenoid valve slow close: Operating Specifications • Flow Range: 10 - 750 L/m. • Pressure Range: 70 - 1034 kPa. |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Yes i have used the Toro valves and they are a good product. My concern would be the chart shows around 15 psi max. All irrigation valves are slow closing to some degree but they still close with a thump on the last little bit as the diaphram seats. The most important thing is they require power to hold them open, and should power fail then they will close. Might not be good. Althought there is a coil avaliable for use with solar controllers that latches and requires a reverse polarity pulse to unlatch the coil. Wheather these coils are interchangeable with these valves i dont know any more but they use to be. (i still have one here somewhere) Pete. Sometimes it just works |
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| kingull Regular Member Joined: 08/04/2010 Location: AustraliaPosts: 44 |
Range of pressure is around 340 foot head. (• Pressure Range: 70 - 1034 kPa.) Powered from mains so if grid drops out, valve will open. I am prepared to accept the final thump but the flow at the nozzle is going to be the maximum I can get from the water line. Solenoid valve slow close: Operating Specifications • Flow Range: 10 - 750 L/m. • Pressure Range: 70 - 1034 kPa. |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Kingull You might try a hammer chamber at the turbine a piece of 6 inch pipe 3 foot long should be enough to absorb the hammer put a tire valve in the top to charge it occasionally as they do seem to saturate over a period of time. All the best Bob Foolin Around |
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| kingull Regular Member Joined: 08/04/2010 Location: AustraliaPosts: 44 |
I have one I built from a gas bottle but dont think it necessary as the jet will be discharging most of the flow by the time the valve is nearly closed. It is hanging up above the spot for the Hydro setup. The other gear there is a 35 gallon minute piston pump and a large single cylinder diesel. All not used now. |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Kingull Good choice for chamber, it may not be necessary with your setup but it is a safety thing and it is better to have it than have all the work fixing blown lines I speak from experience, One of the farmers kids liked the sound of opening the line relief valve and shutting it, ti blew the pipes apart at the joint ripping the threads out, hard to fix, drained the line and welded it. All the best Bob Foolin Around |
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oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
I'm sorry Kingull, but I can't help but feel that you have been wrongly advised. Nearly every windmill (large/commercial etc) is just an induction motor with a gearbox. Until recently when GTI were available, it was the only way to grid connect. We have 2 grid tied windmills that I look after over here, and both are just large induction motors driven by a gearbox. They put out over 100kw in a decent blow. The entire grid over here is probably only 1mw... I think that Tasmania hydro would notice the input..... plus they read the meters for them. You are free to pursue whatever system you wish, but it would be to your own advantage to at least check the truth first. I will be costly not to. 4 pole three phase motors are the best for this application, and are already certified to be grid driven.... think of the implications of your statement, If they are certified to be hard wired into the mains, as a motor, they are certified to be hard wired to the mains. It will require interlock to stop you wasting power if the motor rpm drops below synchronous. The moment you lose grid the rpm will change, voltage will change, frequency will change...... if it was able to be excited by some other appliance with enough capacitance to keep it going. One or all of these things can be used as the interlock device. In the real world, I can't imagine what circumstances would allow the motor to self excite... but the interlock devices are cheap, simple, and recognised by the authorities..... even the 20 year old stuff over here. Try Breezy and read that. Maybe you will realize some one has their own agenda to peddle. I have no financial interest in what you do. Notice they use a 7.5hp 3ph unit to achieve 5kw output. You will notice that a 5625 watt motor in this configuration is good for 5kw output single phase... and seems to be certified for this in the states. So your guess work seems to be at odds with this construction. You only wanted a KW or so, a 5kw unit would easily do this. A single phase unit is less efficient at this caper, thus we use a four or even 6 pole 3 phase motor. 2 pole is feasible, but I have not been involved with 2 pole grid tie. 2 pole motors seem to use more end wire loops, and smaller stators. The wiring is less efficient, but should work nearly as well none the less. There are discussions on this site where we go through the physics and numbers for three phase star delta configurations, and what it means to phase resistance and current and voltage quotients. Might be worth a read. Look also at the requirements to grid connect these things. It is tough in the States, but perfectly easily done. Yes you still have to jump the same hurdles as using a normal grid tie. They also sell a controller to do the work for you. I'm happy for you to do your own thing, but have to straighten out misinformation as soon as I become aware of it. Grid tied induction motors are old technology, used the whole world over... right up to the big boys. The new PMA ones are not.... but all the ones with gear boxes (which are nearly all of them) are simple induction ties....other wise they would not need a gearbox. I'm fairly certain that all those windmill farms are legal. What is not legal, is grid tieing without appropriate inspections and meeting the guidelines from the power generating authorities..... what ever type you chose. I wish you luck with your installation. .............oztules Village idiot...or... just another hack out of his depth |
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| kingull Regular Member Joined: 08/04/2010 Location: AustraliaPosts: 44 |
Problem is that my high heads on irrigation required draining the tank every few days. The piston pump also damaged pipes due to pulsing and they were all buried class 12 50 mm. I replaced it with a multi stage Grundfos and no problems now. Only 1.5 HP but really performs. Nice high head and massive flow rates. |
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| kingull Regular Member Joined: 08/04/2010 Location: AustraliaPosts: 44 |
Hey Oztules. Maybe I am too old at 75 to take this on and you make one perfectly accurate statement. I can legally connect an electric motor to the mains. "Bingo"! Looks like that existing 5 HP 4 pole motor sitting precisely where I want the Hydro unit is "The GO"! The potential on this site is probably more than hundreds of kilowatts when it rains. Ok so I guess star connect (2c Cap) and indirect drive as the Turgo ideal RPM is 2750. Multi jet it as I have several water sources from gullies and existing high dams. Certainly beats a conglomeration of DC AC componentry and saves a lot of dollars. Just a little work on protecting over RPM if grid drops out and that part is "A piece of cake" Dump the jet water instantly. Anyone want a copy of NASA SATA RAID XPSP3 as a bonus? Every boot time it replaces system components. I put it on an old dual pentium PC and its faster than my hot PC. The Russkies developed it and called it Nasa SATA.(comedians) Billy Gates has been kept busy blocking all the downloads. Hehe! Took me three downloads and three days to get a good ISO. Supports all latest "moboes" with Raid and SATA controllers. |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Kingull To follow on oztules we had a auxiliary generator set up at the workshop to stop mains sagging during critical welding it was a 50kva alternator driven by a 100 hp ruston engine and it was paralleled on the mains and it had a line dropout relay to disconnect it from the mains should the mains go down and another relay I cant remember what it was called to disconnect it from the mains should the engine fail, it was connected by the local electrician and approved so it wasn't a problem. Water pulse energy can and does cause problems with plastic pipes and couplings that is why the piston pumps have faded out and multi stage centrifugal have taken over. If you have a foundry down your way you can get the cups cast and bolt to a plate and make your own, I say this because most of the pelton wheels I have seen are to small in diameter and loose out on torque needing to opperate special high speed generators or have power robbing gearing, fast things wear out much quicker than old and slow machines, With a grid connect 3 phase motor set up all you need to do is to set the flow rate to slightly overdrive the unit monitor the feed in current with an AC amp meter to set the load, this can be done by a multi jet system or a choked single jet. very simple nothing to break die or let the smoke out. With the constant pressure you have from a constant head height it should be very stable. Keep up the good work. All the best Bob Foolin Around |
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| kingull Regular Member Joined: 08/04/2010 Location: AustraliaPosts: 44 |
Now reading "Motors as generators for micro Hydro generators by Nigel Smith" Very very comprehensive. I wonder why my head hurts? |
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Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Aha, "interlock". I wondered how the power wasting issue was addressed ever since oztules first mentioned this clever (but new to me) idea here. Now, I wonder just how this 'interlocking' works? It would be nice to have one of your simple & concise explanations on that here. Thanks in anticipation  Klaus |
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SSW_squall Senior Member  Joined: 20/03/2010 Location: AustraliaPosts: 111 |
Hi kingull, wasn't suggesting you'd be doing any shonky electrical installation, i didn't know you ahd that level of experience. It's just about keeping the pen pushing penny pinchers happy!! High quality discussion.... The way i see you could go down a couple of differnt routes, which really depends on the average flow and therefore power that your water source can manage: If your looking at max 1L/s or abit more than a 1kW at 60% efficiency, i reckon the grid tie inverter is the way to go. Because the GTI then handles all the interface with the mains which would only have to be single phase and would handle variations in flow and turbine RPM better. It could be more efficient overall as small single phase induction motors are not as efficient as larger 3 phase ones. One the other hand if your talking 2L/s or more (2kW plus) then the grid tie induction generator rig starts to look more attractive. In this case you'd want to use a 3 phase machine, which may add expense if you don't already have 3 phase at your distribution board. I agree with OZ a 4pole Induction machine would be preferable and more reliable. In either DC or AC case i'd agree with VK, you want to get the turbine RPM down, for the sake of reliablilty and wear alone. I was going to suggest: buying the stainless steel turgo spoons from Hartvigsen hydro and getting a larger custom made disc to bolt them to. If you could come up with a CAD drawing for the disc, you'd be able to get it laser cut out of 4-5mm stainless. We get brakets for our Cinema horn loudspeakers laser cut out of 3mm mild steel into all kinds of crazy shapes... It would probably cost less than about $200. Just my thoughts AB Einstein: Everything should be made as simple as possible, but not one bit simpler |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Kingull I like the Idea of ssw-squal re the getting a plate cut ahd mounting available cups on it, only thing I would go for a piece of 3/4 inch mild steel plate and either get it epoxy coated or galvenised, and it will last longer than us. The extra weight acts a flywheel and smooths out the running a bit also I suspect it would be cheaper than SS and make it as large in diameter as practical. All the best Bob Foolin Around |
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| kingull Regular Member Joined: 08/04/2010 Location: AustraliaPosts: 44 |
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| kingull Regular Member Joined: 08/04/2010 Location: AustraliaPosts: 44 |
Hi Bob, I dont have a lot of time. Just rebuilt my dozer. Have to rebuild our tractor. Rebuild supports on two sheds and on and on. 120 acres and cows and fencing. Not much time for experimenting. Might do as you suggest for second Hydro. Can have a river at the property lowest point when it rains. So make a big one and or find a big centrifugal pump and modify it a little. Then use the 5HP 4 pole motor as a generator. another thought is a big gear pump but they are low speed and not terribly efficient. I am going to stick to the high head turgo with the Pacific Scientific PM motor as it will put out the voltage to suit a Sunny Boy GTI. Reason is that I wont need to adhere to regulations on the DC side and the Sunny Boy can go beside the Latronic unit and be all nice and legal. |
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| oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
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| oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Tinker... Interlock is technobabble for relay. It is very simply implemented, as the rpm of the system tells us most of what we need to know really (we measure more than that over here ....to placate the authorities and to keep the machine together. (It must be demonstrated that the interlock will unload the grid in case of failure.) This is most simply done with a magnet attached to the motor shaft. A hall effect diode senses this magnet rotating past, and provides a pulse train in sync with the shaft. From that we can derive a frequency. You can probably see where we are going with this already. For a 4 pole motor, we have synchronous rpm at 1500 rpm for a 50hz system. So whilst ever the shaft speed is less than 1500, we dont connect the motor to the grid via the relay. At >1500, we can pull in the relay. The motor will start to drive power back into the grid in proportion to the slip graph of the motor. This is mostly in a tight range, but the rotor bar resistance will extend or tighten that range, depending on the R of the rotor bars. If the rpm drops below 1500 rpm for a preset time, we drop the grid until the 1500 is exceeded for another preset time, then connect again. As the rotor speed increases, the slip starts to increase, and more and more torque is used to rotate the shaft, and more power goes up into the grid. We can set an upper limit to this if we wish, ie if the slip gets excessive, we know we have exceeded our power levels, and if this happens for some preset time (say 3 mins), we dump the grid and pull on the brakes. If goes up further while waiting for this 3 mins, we instantly hit the skids, as the grid must have been lost, and we are on the way to over speed. So from just measuring the RPM, we know when to pull the grid on, or dump the grid off, or know that the grid has dropped out, and we turn off. We use anemometers to know when to turn the brakes off, so it can freewheel up to generating speed (1500 rpm), and know if it is too windy, and hit the brakes. It is horribly simple. We also monitor the frequency of the mains, voltage of the mains, brake oil pressure, sway relay, temperature etc etc. But it could all be done from the RPM is you wanted to skimp. So the interlock is just a fancy way to say "safety and technical reasons to pull in the grid," and " reasons to disconnect the relay from the grid" We put all the results of these reasons into a series string of N/O relays. If they all are happy, the series string end up all closed and it happens. There are some parallel strings too. Only the anememeter and safety stuff need be closed to get the brakes to release. etc etc. Only one parameter need release it's series relay, and the thing stops until they are all ok to go again. ...........oztules Village idiot...or... just another hack out of his depth |
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