Hydro choices, location and turbine type

[Jedon]

I'm sure there used to be pipes as well as many pelton wheels up here a hundred years ago, this area was a mining mekka. I'll check the closest junk yard, maybe they have stuff like that. I was thinking 3" would be about the right size?

[Crofter]

Yes around 3" seems like reasonable. Probably about sch 20 and gets used for air lines. Good for over 100 psi and burst strenght higher. Not thick enough for any amount of corrosion allowance but good to prove the concept. If you cannot get the fittings or if the grooves are damaged a half handy welder can join lengths up pretty quick. If the ground is not too irregular, multiple lengths can be joined and snaked in with a skidder or tractor if you dont have to satisfy any quality inspector but yourself.

[Jedon]

Way too steep and rugged for machinery and I only have a big ol 2wd tractor anyhow so this will all be done by hand although I can bring pipe down in my 6x6.
http://stockton.craigslist.org/for/1828718912.html
Would irrigation pipe work?
http://sacramento.craigslist.org/grd/1820751260.html

[Crofter]

Yep, that is the kind of stuff! I hadnt thought of the aluminum as it does not lend itself to field welding but if the grooves are there you are in business and can switch to steel for any pieces you have to special fab.

[Jedon]

Well my Harris Hydro setup came today, 4" pelton wheel with a 120V DC variable field strength PM generator.
My brother and I ran 400' of 3" PVC and I made a small dam and intake.
I bought two 500ft rolls of 10g THHN from HD and will use some old well pump wire for the remaining 150ft.
I'll be putting the wire in 1.5" PVC
I thought I should get around 40psi but got 19psi so that is disappointing but we'll see how it works out, still 100-500W expected.

[RogerAS]

Well my Harris Hydro setup came today, 4" pelton wheel with a 120V DC variable field strength PM generator.
My brother and I ran 400' of 3" PVC and I made a small dam and intake.
I bought two 500ft rolls of 10g THHN from HD and will use some old well pump wire for the remaining 150ft.
I'll be putting the wire in 1.5" PVC
I thought I should get around 40psi but got 19psi so that is disappointing but we'll see how it works out, still 100-500W expected.

Jedon,

How in the world does one vary the field strength of a permanent magnet generator?

R

[sailawayrb]

Roger, there should be a way to adjust/set the air gap (the distance between the alternator rotor and the stator).  The gap is typically set to maximize power at the operational RPM.  There is also a minimum gap distance that you should never exceed to avoid having the rotor contact the stator as the bearings wear.

Jedon, I assume the 19 psi is the dynamic pressure (i.e., the pressure measurement with water flowing thru pipe) where the Harris is located.  What was the static pressure (i.e., pressure without water flowing)?  The static pressure should be 0.433 psi times the vertical distance between Harris and intake.

http://www.nooutage.com/hydroele.htm#How%20much%20power

[RogerAS]

Roger, there should be a way to adjust/set the air gap (the distance between the alternator rotor and the stator).  The gap is typically set to maximize power at the operational RPM.  There is also a minimum gap distance that you should never exceed to avoid having the rotor contact the stator as the bearings wear.
snip...

I see how this can be done in an axial flux alternator, but for the life of me I cannot see how this can be done in a standard "squirrel cage/motor" type alternator. Unless the rotor is able to shrink and expand, or move the magnets closer and farther away from the stator.

R

[sailawayrb]

I see how this can be done in an axial flux alternator, but for the life of me I cannot see how this can be done in a standard "squirrel cage/motor" type alternator. Unless the rotor is able to shrink and expand, or move the magnets closer and farther away from the stator.

R

Right, this is definitely NOT a "squirrel cage/motor" radial flux design.  This is indeed an axial flux design.  The rotor is a disk (containing 16 PMs) that rotates an adjustable air gap distance above the stator.  The stator is a thicker, stationary disk that fully encapsulates 12 electrical windings in epoxy. Here's all the details:

http://www.microhydropower.com/Articles/WaterRites.pdf

http://www.microhydropower.com/How%20it%20Works.htm

http://www.microhydropower.com/Manuals/LH1000%20Manual12-08nrec.pdf

http://www.youtube.com/watch?v=4teOp0YYmwY

Since hydro is 24/7/365 and done in a challenging environment, low maintenance and high reliability take design priority. On these commercial units, you typically have to replace the bearings about every 10,000 hours.  12/24/48/120/240 VDC are the common outputs.  

I designed a DIY version that uses a standard motor boat prop and more robust, off-the-shelf bearings. I also designed a DIY cross-flow "Banki" turbine that I am considering as well.  The PM alternator design is the same for both and will use off-the-shelf NdFeB PMs of the type one can easily obtain from Forcefield and be of the two rotor (12 PMs per rotor) and one stator (9 ironless windings) topology.  

I chose/plan to use my low head, high flow creek to produce about 1200 watts at 120 VDC. Excess power (i.e., the power not used for the normal house electrical loads) will be used to minimize propane usage, which is required for the stove/dryer to keep wife happy, and also used for domestic hot water and hyrdonic floor heating (which will be our automatic heating mode when we are away and which will backup/supplement our passive solar house design and masonry heater).  OR charges about $1000 for the initial hydro power approval permit (which is good for 20 years and is renewable) and than $15/year.  So I consider this a micro hydro, passive solar, RE cogen solution  

[Jedon]

According to the manual it's done with an extended drill chuck and an allen wrench :-)

I spun the wheel up but then a PVC/ABS 3" to 2" adapter popped off, I was going to replace it with a PVC one anyway but the glue for gluing PVC to ABS is not very good apparently.

Oh well, next week when the rain stops I'll give it another go.

[Jedon]

I got it working! The Tristar TS-60 PWM charge controller limited the input voltage to the output voltage ie the batter bank voltage which was half the designed voltage of the hydro unit and so didn't work. I replaced that with an IOTA AC 13A 48V ( 54V ) battery charger and got the pelton wheel spinning up good with all the water currently available so it was making 208V DC. The IOTA can accept DC ( although it doesn't say so ) and when loaded it dropped the voltage to 114V then eventually to 107V but it works, I'm not sure how many amps since I don't have a DC ammeter on hand ( yet ). I put a 20A AC breaker between the hydro output and a standard AC power outlet, and another 20A AC breaker between the IOTA and the battery bank. I know I shouldn't use AC breakers for DC but I'm really just using them for switches, I'll get some DC breakers eventually. Usually in the morning my 8 golf cart batteries are at 48.6V but this morning they were at 50.5!

[Jedon]

I finally got a multimeter that will read DC current and it's measuring 5.26 amps at 108V DC! 560 Watts or so, I'm stoked. 13+KW/h's per day should easily power the house 24/7 but for some reason it isn't so I need to trace that down now. My intake gets clogged a bit, anybody know of an affordable source for a small ( like 12x24 inch ) coanda screen?

[mbryner]

Awesome Jedon!  I'm jealous, that's over 12 kwh/day for free.

I thought I found a good site for coanda screens for you, but the co. this guy used is now out of business.   But it's a good read anyhow:

http://www.homebrewhydro.com/coanda_water_intake.html

[sailawayrb]

http://www.hydroscreen.com/products/hydro_turbine_diversion/index.html

http://www.conn-weld.com/sieve.htm

http://www.dulas.org.uk/coanda/content/

[Jedon]

Thanks both of you for the links, I did email with Hydroscreen previously but they are around $350, I was hoping there was a cheaper alternative.
Conn weld looks pretty industrial but I should contact them to see if they would consider a pittling order.
I have been to home brewed hydro but like you say they aren't selling them anymore :-(