Built a new AC hydro generator!

[XeonPony]

Hello been a long time visitor of this site and decided I should share my recent successful hydro project.

I'm using a  2Hp 230V motor 2 speed, Using a hot tub wet end (4Hp impeller) in revers and the high speed winding with 200 Uf of ballast capacitor with 200' of 2" polyethylene pipe. At current I'm not sure of the current drop of elevation but I'll try and get that for you all.
At current I have about 15' of head with a high volume of flow, With no load I am getting 102V @ 30Hz Ac, under load I am getting 89V 30-29Hz.
The goal is eventually to get a solid 120V @ 60Hz but for now the system is driving a 25w compact fluorescent with out issue and soon a 12V 15A battery charger.

Addition:
I'm using a method of modifying a standard Induction start capacitor run motor. To do this you bridge the centrifugal switch to lock in the run winding, then you add run capacitors to the phase you intend to pull power from. So in my case I have my capacitor bank on the high speed winding, I have yet to ascertain what my max power draw will be from the generator, Tomorow I hope to have some more info for you along with the pictures.

Pictures to follow soon

Comments and questions are quite welcome!

[hydrosun]

Congratuation on getting it to work. A pump as turbine is still a black science to me. I do know that matching the head and flow to the pump is critical to maximize the efficiency. I'm guessing that  larger penstock pipe would help lower pressure drop into the large opening of the pump. That's assuming you have more water available. To get 60 hertz you will need more head with your existing setup. Conversely the motor would need to be changed to a lower speed one. I see you are using different windings already to get the higher hertz.  The voltage drop from no load to loaded makes me think the load could be increased to drop the voltage closer to 50%. Dustin will probably know more about that and have ideas about capacitors.
 Have fun playing with the water.
Chris

[XeonPony]

Well flow is good all I need to switch to a smaller impeller spacing, flow and head are good. Looking for a 1725rpm 120v motor to replace the 230v motor.

All peramiters are covered on that end, in futur will be switching to a pelton wheel, but it is working better then I innitialy expected.

[Harold in CR]

 Looking forward to the photos. I am VERY interested in your measurements of head-flow- and such. Sounds like you have things well in hand.  Congrats.

[Ungrounded Lightning Rod]

Running a hot tub pump as a turbine sounds very interesting.

[XeonPony]

here are the pics

Addition:
The draft tube is 4", eventually it will be sealed and made air tight then purged of air to add some negative head to the positive head. I plan on running at least 20+ feet of the 4" PVC. eventually I intend to add a large amount of 4" to the positive side of the system then 3" then down to the 2" for the final run.

[frepdx]

cool project! What's the flow rate out of the turbine?

Friction losses in the feed pipe are going to limit available power to about 60 watts, with maximum power at about 30gallons/minute and a 5' head loss. here's a link to calculate friction losses in pipe - http://www.engineeringtoolbox.com/hazen-williams-water-d_797.html

[Harold in CR]

 Pretty slick. Thanks for posting the photos.

[XeonPony]

cool project! What's the flow rate out of the turbine?

Friction losses in the feed pipe are going to limit available power to about 60 watts, with maximum power at about 30gallons/minute and a 5' head loss. here's a link to calculate friction losses in pipe - http://www.engineeringtoolbox.com/hazen-williams-water-d_797.html

Raw flow rate is some where around 44 to 50 gallons per minute, dynamic head is around 5 to 10 psi static head is 15 psi.

I know the pipe is un-ideal, as I said eventually I'll be doing 150 feet 4", 150 feet 3", 150/200 feet of 2" hard abs going to a short run of polyethylene to couple it to the turbine

I have tons of engineering calcs on hand, thanks any way for the link, when I get my main system running again I'll rig up an FTP server for you guys to have access to my calcs, took a while to find a good friction loss and flow calculator and converters for designing piping runs and refrigeration systems.

Addition:
Light has been running stable for 42 houres now!
Going to put in a narrower impeller to increas rotational speed, by doing so I will reduce the nominal torque gained by the water trading it for rotational speed.

[frepdx]

With 15pis static pressure, your head must be close to 30'. The 2' pipe should bring about 200 watts to the turbine.

[XeonPony]

With 15pis static pressure, your head must be close to 30'. The 2' pipe should bring about 200 watts to the turbine.

just so ya know that's messured from another 120' of 3/4 pipe via a 90 degree (You see the tap comming off the 2" near the turbine).
Other then that 200w will do me just fine for the interm

thanks for the ruftimate.

[dbcollen]

Your calcs are way off, with 10 psi and 50.5 gpm, there is 153 watts available in the water, you would do quite well to get half that to your batteries.

Dustin

[frepdx]

Your calcs are way off, with 10 psi and 50.5 gpm, there is 153 watts available in the water, you would do quite well to get half that to your batteries.

It's a 15psi static head, not 10psi - read the thread. But these are just rough guestimates, no need for 3 significant digits, dbcollen!

[XeonPony]

well tested it to a 115w so far and volts haven't budged (I'm at my critical flow to maintain volts now) so I need at least 50 feet more pipe @ 4" to get the rpm up & to get it to the 120v that I need, frequency will be stuck around 30-50Hz as I'm purposely choking off a 230v motor to push the 120 out.

And I'll get all the energy I can to my batts Been in electrical for many years now, I know how to squeeze a system of all its power

May transmit the power at 6Kv or very least going to be transmitting at 300v, either way line loss will not be a significant factor!

[Opera House]

I've pulled my hot tub pumps apart many times and am impressed that you are getting results that good.  I have a 30 foot cliff and a ground water problem in my yard.  This could be a solution.   I am curious what result you get if the start cap is removed once it is generating power. 

[dbcollen]

FredPx, You will never have static pressure on a running turbine, and if you actually read the original post he clearly states "Raw flow rate is some where around 44 to 50 gallons per minute, dynamic head is around 5 to 10 psi static head is 15 psi." and I was calculating for best case, using the data given, but thanks for being a jackass.

Dustin

[dbcollen]

With 15pis static pressure, your head must be close to 30'. The 2' pipe should bring about 200 watts to the turbine.

And since you are trying to be so precise, 15 Psi is exactly 34.659562226622702937513430580363 ft of head at 68f

Dustin

[XeonPony]

I've pulled my hot tub pumps apart many times and am impressed that you are getting results that good.  I have a 30 foot cliff and a ground water problem in my yard.  This could be a solution.   I am curious what result you get if the start cap is removed once it is generating power. 

The fact I'm working with a pump shop atm helpped alot in this endevour, new berrings and shaft seal did considerable good in geting it running.

I'm using a 4Hp imppeller and wet end on a 1.5Hp motor.

[Opera House]

"I'm using a 4Hp impeller and wet end on a 1.5Hp motor."

For those not familiar with hot tub pumps, these impellers screw on and can be changed within the same body for different motor loading.  Many pumps are changed because the seals go bad.   Leaking seals can go on for a long time and can make the pump look pretty bad.   My pumps no longer have the mounting pedestal.  Lots of old tubs on Craig's list for haul away if you can figure how to cut one up or use it as a coy pond.  Seals at a local shop are quite expensive.  Ebay is quite cheap for seals and I buy four at a time to get me through a couple years.  I wonder what results you would get mounting it vertical and cutting open the inlet or mounting four pipes in an open frame.

[frepdx]

FredPx, You will never have static pressure on a running turbine...

use the static head to calculate the potential, the dynamic head is simple the static head minus losses.

40gpm through 200' of 2" pipe gives about a 5' head loss. 45gpm/60 x 8 lb/gal x (30'-5') = 150 ft-lbf/sec = about 200 watts. (note static head minus the pipe losses)

Your calcs are way off, with 10 psi and 50.5 gpm, there is 153 watts available in the water.

no, that's wrong. HP = PSI x GPM ÷ 1714,  10psi  x  50.5 / 1714 = .29 = 220 watts.

[dave ames]

XeonPony,

 super cool!!   thank's for the share.

curious if anyone thinks that it may do even better in a perpendicular orientation? sure would be nice to have some extra pump heads to play with flow mods.

bet we see some more of these pop up now!

kind regards, dave

[Opera House]

I've been thinking about your start field being wired in all the time.    I had a thought it might be better if it was wired back to itself instead of the output line voltage.  As it is (I think)

L1----- start winding-------start capacitor---- shorted switch-------L2

to

L1----- start winding-------start capacitor---- shorted switch-------L1

[XeonPony]

"I'm using a 4Hp impeller and wet end on a 1.5Hp motor."

For those not familiar with hot tub pumps, these impellers screw on and can be changed within the same body for different motor loading.  Many pumps are changed because the seals go bad.   Leaking seals can go on for a long time and can make the pump look pretty bad.   My pumps no longer have the mounting pedestal.  Lots of old tubs on Craig's list for haul away if you can figure how to cut one up or use it as a coy pond.  Seals at a local shop are quite expensive.  Ebay is quite cheap for seals and I buy four at a time to get me through a couple years.  I wonder what results you would get mounting it vertical and cutting open the inlet or mounting four pipes in an open frame.

Seals cost 20 bucks or less here!, and usually easy to change providing you take care to lube the shaft be for installing the impeller.

The intake volute is what primarily guides the water and accelerating it, so doing any thing to interupt the valuting would reduce the nominal loading of the impeller reducing the energy extracted from the water. That is the nice thing of using the pump, it is as good as it gets right out of the box, any thing better will need to be purpose built imo

[XeonPony]

I've been thinking about your start field being wired in all the time.    I had a thought it might be better if it was wired back to itself instead of the output line voltage.  As it is (I think)

L1----- start winding-------start capacitor---- shorted switch-------L2

to

L1----- start winding-------start capacitor---- shorted switch-------L1

Not sure I'm geting you?

Currently it goes:

Ln = Common
L1= High speed (3425rpm)
L2= Low speed (1725rpm)  < Is shorted (How I got the pump free)

Ln ----Capacitor bank----L1
Ln-----shorted start switch -----start winding.  start cap removed and wires spliced togeather.

I'll take some clear photos tonight and try to draw a schematic and scan it for you guys. I'm willing to give your wiring ideas a test.

[Opera House]

I used L1 and L2 in a convention I am more used to, two line terminals

I would have suspected that shorting the start and high speed windings together would reduce power.  Many small generators have a separate winding in series with a capacitor to promote oscillation.  As follows using your terminal convention.



Ln -------power out---------------L1


Ln -------start winding----capacitor----shorted switch------ Ln

[XeonPony]

Ok now I got you.

Here are some detailed pics of the electrical

[Opera House]

Seals cost 20 bucks or less here!,

Here too, but just checked on ebay you can get three PS-1000 seals for the Waterway shipped for $15 total.  I'm down to one seal so it is time to order some more.   One of my pumps lost the low speed, open, but it was my fault.  That switch went bad and popped in another one.   Then the rotor rubbed through a wire.  Pull it apart and then another one rubbed through.  It was winter in the snow so I ended up jumping the low and high speed together.  Time to revisit that and lower my electric bill.

[XeonPony]

Seals cost 20 bucks or less here!,

Here too, but just checked on ebay you can get three PS-1000 seals for the Waterway shipped for $15 total.  I'm down to one seal so it is time to order some more.   One of my pumps lost the low speed, open, but it was my fault.  That switch went bad and popped in another one.   Then the rotor rubbed through a wire.  Pull it apart and then another one rubbed through.  It was winter in the snow so I ended up jumping the low and high speed together.  Time to revisit that and lower my electric bill.

OK!  Now I understand what ya mean!!!!!   I just got a couple spade crimps and will be testing that wiring set up out when I get home today.

I tried it that way initially with out success but at that time the pipe run was still to short, so I'll try my luck out

[XeonPony]

I used L1 and L2 in a convention I am more used to, two line terminals

I would have suspected that shorting the start and high speed windings together would reduce power.  Many small generators have a separate winding in series with a capacitor to promote oscillation.  As follows using your terminal convention.



Ln -------power out---------------L1


Ln -------start winding----capacitor----shorted switch------ Ln

I tried your methode and all generating stopped. How ever I did leave the start cap leads seperated this time and noticed less rotor drag and gained a volt or two.

[XeonPony]

Up date:

Added 18' of 4" to the pipe run and 4' of 4" on the draft tube to generate negative head and I am now at 101V AC 30Hz and I can run my laptop now off the turbine!

At about 60w load it drops to 85V, will soon be adding another ten plus feet to see if that gets me to the 120 mark (Keep in mind I'm using a 230v motor as the generator at the moment!). Be for I can get the motor running 100% its proper voltage I need to acquire a 240v to 120v transformer capable of handling 500w min preferably I want one capable of 1Kw for good head room for future upgrades and such or if I move sites.

[slopecarver]

Just a little tip when taking closeup pictures of something put your camera in something called macro mode, generally designated by a flower on a button. Macro mode changes how the camera analysis's whether the picture is in focus or not, It knows to try focusing up close. It should be known that you can be too close when taking macro photos. Most digital cameras can focus no closer than 2-5 inches. Good Luck, an hot tub impeller pump is pretty ingenious regardless of how much power it can actually output!

[XeonPony]

thanks but I was in macro! some times I need to hit it several times to free the iris so the light saturation can be adjusted lol, it does great in normal photos, but as you can or rather can't see it has troubles being actually close, if I messed with it long enough it would have worked but for what I wanted to show it did the job albeit blurry.

Thanks for the compliment, I noticed not many had tried it be for so thought I'd post it, as the pumps can be some what easily grabbed from the wreaking yard or free sections of the local news rag! Not to mention ease of repair!

I hope to see more threads with the pump set ups being used

[Ungrounded Lightning Rod]

Up date:

Added 18' of 4" to the pipe run and 4' of 4" on the draft tube to generate negative head and I am now at 101V AC 30Hz and I can run my laptop now off the turbine!

At about 60w load it drops to 85V, will soon be adding another ten plus feet to see if that gets me to the 120 mark (Keep in mind I'm using a 230v motor as the generator at the moment!). Be for I can get the motor running 100% its proper voltage I need to acquire a 240v to 120v transformer capable of handling 500w min preferably I want one capable of 1Kw for good head room for future upgrades and such or if I move sites.

This sounds like your RPM is/was just a tad below the resonance of your capacitor with the motor's coils.  You can cure that by adding a bit more capacitance to lower the resonance, or by increasing the RPM (which would require more head, a smaller radius runner, or reaiming the jets a tad inward).

With your caps on a separate winding (so the load's power factor doesn't confound things) the generator will start putting out when its RPM goes above the synchronous speed defined by the inductor/capacitor resonance.  If you have enough push the excitation will build until the rotor saturates, then the unloaded output voltage will be a tad over the rated output voltage (because the rotor doesn't QUITE saturate in motor service) times the ratio of actual to rated RPM.

So with your resonance at 30 HZ and your rotor spinning at roughly half the rated RPM (plus twice slippage) your output voltage will be about half the rated output voltage.

More capacitance lowers the resonance, allowing the motor to generate at a lower RPM.  But the fixed magnetic field of the rotor saturation times the lowered RPM means you also get lower output voltage.