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New Stator
By chainsaw, Section Hydro Posted on Wed Oct 28, 2009 at 04:32:24 AM MST
New Stator

After 4 years of constant use my micro-hydo stator has bit the dust. When this unit was constructed I used the Hugh design for an eight ft. dual rotor mill, 48v (100 turns 15g wire per coil). I used the 48v winding to reduce line loss(300 ft.) to the battery bank(24v). I use a mx60 for mppt voltage reduction. My free wheeling unloaded voltage is 130v. Using the 40% voc the mx60 locks on at about 50v and gives the most wattage (100) to the batteries which closely corresponds to the 48v winding.
I had no idea at the time what the volts,watts,amps would be until I got this unit in the water and actually turning. Does any one have any ideas on the new stator windings(turns, gauge or same as before) for more wattage. Since there is only so much water power available have I reached the maximum output(watts) and most efficient use of this alternator? Which would be a pure accident on my part. All comments are welcome.
Bill

New Stator | 15 comments (15 topical)

Re: New Stator (3.00 / 0) (#1)
by hydrosun on Wed Oct 28, 2009 at 08:45:10 AM MST

If your voltage drop on the wire was still substantial then you could wind the stator for a higher voltage, but then would have to have some way to clamp the open voltage to keep from damaging the MX-60. I've used solar panels in parallel with the hydro into the MX-60 for years now to clamp the voltage. I put in one system that runs at just over 100 volts with solar panels with open circuit voltage of 120 volts that clamps the hydro output at just over 130 volts.
If you don't have much voltage drop in the wire you won't gain much by going to a different voltage stator. I am a bit puzzled on the open voltage of 130 volts and the maximum power point of 50 volts. I would think it would be closer to 60 volts. But the power curve for a hydro is pretty flat in the middle so the difference is slight between 40 and 50% of the speed of no load. If you had substantial voltage drop in the wire it would push the voltage at max to the higher edge of the voltage window.
Chris

Re: New Stator (5.00 / 1) (#15)
by Lowhead on Tue Nov 03, 2009 at 11:19:46 AM MST

Can I ask some questions about your hydro/pv connection? Are you saying that you run both the PV and hydro inputs into the MX60 without any trouble? I've just finished installing a PV system (just to get a grid tie connection) and tomorrow after my local inspector signs off (keeping fingers crossed) the utility will let me throw the switch. After that I'm planning to hook up my hydro system.

The PV system is this:
18 Kaneka GSA60 watt panels wired in parallel for 48V.
MX60 MPPT controller
Outback GVFX3648 inverter
8 Trojan T105
Midnite solar Epanel Plus and battery box located in the basement.

I own an old millpond dam located on the Sudbury river 330 feet from the house. Average flow is 12,000 GPM and my head is 9.4 feet. I'm using an ES&D LH1000 low head turbine. Its the same PMA as on the stream engine. The turbine is mounted in a water box that is elevated on a welded steel frame and an 8 inch x 18 foot long PVC pipe feeds through the dam and into the box. I know the 8 inch PVC pipe is a bit undersized and with two 45 degree and one 90 degree elbows I'm seeing a measured head of 8.5 feet. I expect that will give me about 800 watts with about 800 GPM. The 90 degree elbow could be taken out of the system. Currently it is how I shut off the flow by rotating the 90 degree elbow at the inlet (not glued) upwards so that a short length of pipe is out of the water. Eventually I will make some sort of tapered inlet and take this out.

My plan was to run the hydro directly to the batteries but your way is intriguing. I have a C40 that I was going to use as a diversion load into a hot water tank but was thinking of swapping that for another MX60 just so everything is Outback and communicates properly (all it takes is money and I don't have any left). I had talked to Outback about running the LH1000 through an MX60 but they discouraged it because of the open circuit voltage when the MX60 hunts.

My wire length is about 350 feet of 8 pairs of 4mm sq solar wire that I got a good deal on. I can't bury the wire due to wetlands restrictions and it would be nearly impossible anyways. I know the NEC won't allow running pairs to increase current carrying capacity it but was cheap and supple enough to string it through the trees with a combiner box at each end. I can add more pairs later but for now its all I can afford.

[ Parent ]

Re: New Stator (3.00 / 0) (#2)
by chainsaw on Thu Oct 29, 2009 at 04:46:01 AM MST

Chris

You are correct about the mppt voltage. I used the 50 volt mppt value only as an average because of minor variations in flow and air bubbles.

Did you use your solar combination for hydro control or for a more efficient use of the mx60? Since my open voltage is getting close to upper limit(mx60) do you think I should just wind same as original? What type of hydro unit are you using?

Thanks, Bill

[ Parent ]

Re: New Stator (3.00 / 0) (#3)
by hydrosun on Thu Oct 29, 2009 at 09:04:18 AM MST

So you picked the voltage instead of letting the MX-60 going open circuit every 15 minutes to pick the best voltage for the most power. With the solar panels connected I usually let the MX-60 do it's job of varying the voltage to get the most power if conditions change. Without the solar to clamp the voltage I'd be nervous that some spike in the voltage would blow a capacitor in the MX-60. I have blown two when the solar was shut off while the hydro was running. Luckily they were quickly replaced by Outback. I'm within driving distance of the factory.
I use the MX-60 on hydro to be able to generate at a higher voltage to keep down the power losses in the wire to the battery. The solar panels were part of the mix because the stream dries up in the summer. The ability to vary the voltage to get the most power is a bonus. I'm using Harris Hydro PM units that can vary the strength of the rotor by moving the magnets to match the power available as the stream flow varies. With the MX-60 I don't have to move the magnets, I just keep them at full strength. As I cut back on water available the voltage rises as the MX-60 partially unloads the hydro, allowing the pelton to maintain it's 50% speed relative to the water.
Without solar panels I'd stay with the same stator you've been using that keeps the open circuit voltage under 140 volts. What happened to the stator that it fell apart? Wrong filler?
Chris

[ Parent ]

Re: New Stator (3.00 / 0) (#4)
by hydrosun on Thu Oct 29, 2009 at 09:10:52 AM MST

What is the drop and gpm to get 100 watts? If your efficiency is much under 50% then you may want to experiment to get more power. Harris hydro may be up to 70% efficient except at the upper and lower extremes.
Chris

Re: New Stator (3.00 / 0) (#5)
by chainsaw on Fri Oct 30, 2009 at 04:31:23 AM MST

I have 22 ft. of head and enough water to run 4 7/16 inch nozzels at full flow, as water flow slows I reduce nozzel size as necessary to keep my penstock full. Stream does not dry but during local drought last year flow was down to two 5/16 nozzels.

My stator failure is internal(electicial). Started as a rectifier failure, after replacing, alternator only operated a few days before going zero(no ac going to the rectifiers). Since this was my first attempt at stator construction I was surprised it worked at all.

I attended a Don Harris workshop at a local school a few years ago and was quite impressed with Don and his pm alternator. Used his nozzel design to increase my wattage output.

Bill

[ Parent ]

Re: New Stator (3.00 / 0) (#6)
by hydrosun on Fri Oct 30, 2009 at 09:31:07 AM MST

The 4 7/16th nozzles will let out about 48 gpm at 22 feet. At 50% efficiency the hydro would put out 140 watts. Does the 22 feet head account for pressure drop in the pipe when running the 4 nozzles? Size and length of pipe? Where did you get your pelton wheel? How are the nozzles aimed?
The stator failed at some internal connection. I wonder if it was a poor connection with high resistance from the beginning causing the lower than expected output. What was the voltage drop in the wire to the battery? I assume the 100 watt number is from the MX-60 which isn't always 100% accurate, especially if it isn't allowed to go open circuit to recalibrate. I've seen them show 2o watts after the input breaker is shut off.
I'm asking all these questions to see if you can tweek something to produce a bit more power. I played with homebuilt hydro for many years. The trickiest thing was accurately aiming the nozzles at the pelton. I'd have wedges on the pipes to aim the nozzle and would have to readjust them every time I lifted the turbine up to change nozzles. When I changed to a Harris hydro it produced more power but I couldn't justify spending all my time playing with the hydro. You'll have fun seeing what you can change to get more power.
Chris

[ Parent ]

Re: New Stator (3.00 / 0) (#7)
by hydrosun on Fri Oct 30, 2009 at 09:58:53 AM MST

I went back and read the original posting when you were planning your system. Are you still using the part from a brigs motor as your turgo? That could cause the lower than expected output. The numbers you were using then are a bit different from now. Then you were talking about 25 feet head. Are you now allowing for pressure drop in the pipe.? The open circuit voltage was 90, now it's 130 volts. What changed? Did you connect the MX-60 to both the solar and hydro? ( Likely not if the voltage is 130 volts.) I saw you were getting conflicting answers from Nando about doing that. I have direct experience doing that for years. In practice the solar and hydro compliment each other. When they overlap you have more power than you need and the MX-60 starts rejecting some power and letting the voltage rise into the solar and hydro lower output range. The amount of time that this happens is not worth the cost of another controller.
If you haven't put in a real turgo that would be the place the most effort to get more power out of the unit.
Chris

[ Parent ]

Re: New Stator (3.00 / 0) (#8)
by chainsaw on Fri Oct 30, 2009 at 12:14:39 PM MST

My first runner was indeed a cooling fan from a Briggs engine, thats where the 90v figure came from(very inefficient). The 25 feet of head was from level on a stick method. The 22ft is from a later installed pressure gauge at the unit (static 9.5 psi). My present runner consists of 26 orange spoons purchased from h-hydro in Utah. My runner is almost identical to the one pictured on his web site. My penstock consists of 320 feet 4" pvc pipe and is reduced right at the unit to 2" diameter with each nozzle feeding from the 2" pipe. I cannot find my figures for the angle I used for my nozzles. Memory thinks it was between 15 and 20 degrees.

As you can see I have had quite a journey of learning(still not there but getting better) and I'm sure you know, micro-hydro is fasinating and addictive.

Your comments and questions have been appreciated. When I expand my solar in the future I will combine panels with the hydro the same as you have done.

[ Parent ]

Re: New Stator (3.00 / 0) (#9)
by Ungrounded Lightning Rod on Fri Oct 30, 2009 at 04:22:58 PM MST

I wonder if running four penstocks from four slightly different height taps in the water source could be used to automate that process?

I suppose a problem would be to keep them from clogging with flotsam when the level dropped to the tap height. So you'd want the actual tap to be at a clean level then make your stack-of-taps automated valving in a covered standpipe nearby. Interesting plumbing job.

Of course the individual penstocks would have to be nearly the same diameter as the singleton to avoid extra head loss from friction. Could get pricey. Or maybe put the standpipe near the turbine.

Valves probably make more sense. (It's just fun to come up with designs where the working fluid is the only moving part, or close to that. B-) )

[ Parent ]

Re: New Stator (3.00 / 0) (#10)
by hydrosun on Sat Oct 31, 2009 at 11:22:03 AM MST

One of my hydro units runs off the roadside ditch and the flow varies tremendously from day to day. I'm constantly changing the number of nozzles open. Your idea of a stand pipe next to the turbine with tees at 4 different levels to individual nozzles would work to automate the process. Unfortunately the head is around 37 feet so I'd have to work at some height to make it work. Getting the exact height might be tricky. I'd tie a 4 inch pipe to a nearby tree with a reducer to 2 inch near the top and tees out to 4 two inch pipes to each nozzle. The biggest problem might be freezing when the water slows. Gives me something to think about. I've worked out all kinds of ways to open and close valves using weights and water powered valves or electric valves with a pressure switch. None ever got done. All with problems and things to go wrong.
Chris

[ Parent ]

Re: New Stator (3.00 / 0) (#11)
by hydrosun on Mon Nov 02, 2009 at 10:52:52 AM MST

After thinking about your idea I see where it won't work. As the water available becomes greater the water level rises and starts to spill into the next higher tee. It would have to completely fill that pipe up before getting to full pressure. It would be at partial pressure and interfering with the speed of the pelton. If the standpipe is close to the turbine it would fill up quicker but as soon as the overflow started the pressure drop in the penstock would increase and the level in the standpipe would go down. That would make the transition to full pressure for that pipe even longer. Hydro needs to be digital not analog. The flow needs to be either all the way on or all the way off. In between the pressure is lost and it works against the other nozzles. Back to the drawing board.
Chris

[ Parent ]

Re: New Stator (3.00 / 0) (#12)
by Ungrounded Lightning Rod on Mon Nov 02, 2009 at 01:01:10 PM MST

You should be able to use an intermittent siphon arrangement to get it to be all-or-nothing. If you have adequate flow from the source (i.e. you're not using most of the river and your main penstock is of adequate diameter) it shouldn't suck out and oscillate. (If not you could still arrange enough storage at the valving location so it oscillates with a very long period, making the "a nozzle is running out of water" stage a very small percentage of your operating time.)

The trick is to have the difference in height between the opening of the down-facing end of the tap and the level where the water starts running out (sucking out the bubble) greater than the amount that turning on one tap drops the level in the standpipe. If your hysteresis from the siphon is greater than the pressure drop you don't oscillate. (If it's too large all that happens is you don't start up until the head is higher than it needs to be.)

You should be able to construct all this cheaply by putting down-facing elbows INSIDE the standpipe at each tap. If it oscillates, add progressively longer nipples to increase the hysteresis until it works smoothly.

But rather than trial and error you can figure this out in advance: Measure your pressure difference on your current setup with zero, one, two, three, and four jets on. Convert that to inches of water and make your intermittent siphons a bit longer than that when you build your standpipe. (You can use screw-in nipples so you can change the length if you're not sure this will get it right.)

Note that it's reasonable for all the taps to be ALMOST the same height, spaced much more closely vertically than the start/stop height difference, so you get about the same head no matter how many jets are running.

[ Parent ]

Re: New Stator (3.00 / 0) (#13)
by Ungrounded Lightning Rod on Mon Nov 02, 2009 at 01:06:32 PM MST

But at the turnover (start level) you want the bottom of each tap's turnover to be about as high as, or higher than, the top of the next lower one's, so all the flow goes into starting one siphon, rather than getting distributed over several and thus never sucking the bubble out of any of 'em. Similarly you'll want SOME difference between the height of the lower ends so they "suck out" cleanly and one at a time.

[ Parent ]

Re: New Stator (3.00 / 0) (#14)
by hydrosun on Mon Nov 02, 2009 at 06:46:50 PM MST

Thanks, maybe sometime later this winter I'll get some time to play around with a standpipe and syphon.
Chris

[ Parent ]

New Stator | 15 comments (15 topical)

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