Progress and not getting wet

[Heinz]

It's been dry here for a few days so I've been flat out with water turbine stuff. Spent a whole day, dawn to dusk pratting about running the cables down a length of MDPE pipe. I had this foolish idea that it would be easy to pull the cables down 200m of pipe. Wrong. Blew a wooden bullet with fishing line attached down the pipe, then tried to pull some very strong string through with the fishing line, only just managed this as the fishing line gripped the pipe on the few corners that there are. Got the cables 60m in and they would go no further, in or out  Ended up having move all the pipe from the burn to the track, straighten pipe 100% and pull through as two 100m lengths, then move it back to the burn. Got this finished last night by moon and torchlight after the fireworks ran out 
Today I made a space for the turbine, dug a bit out of the slope and added a couple of half sleepers to sit it on.



Hooked the water up and gave it a spin. The yellow bucket needs a 3/4 lid to aim the water downwards but that can wait till another day. It looks like nothing much, but it's taken a remarkable amount of work to get this far so it was very satisfying to see it almost working    Need to deal with the workshop end wiring next.




Blue barrel covers in place.

Steak pie time 

Heinz

[camillitech]

Nice work Heinz,

laughed at your cable in the pipe, been there, got the video, book and T shirt    though you got much further than me, best I've ever done in one length is 50m   Any chance of some more pics of your turbine and runner, and what sort of output are you expecting.

Worked stopped on mine last Tuesday,



when I had to go back to work   but it's been running for six days now at 5 elephants to the bucket and 100psi which is a little over 3lts/sec  

I can't see the outlet now as it's dark when I drive to and from work, normally I can view it from the road, so the wife has been walking down daily to check the flow and pressure. I tell her to put the bucket under the outlet and count elephants   http://lifeattheendoftheroad.wordpress.com/2011/11/01/shonas-back/ Next week should see my turbine in position and producing  

Cheers, Paul

[Heinz]

Any chance of some more pics of your turbine and runner, and what sort of output are you expecting.

Worked stopped on mine last Tuesday,
when I had to go back to work   but it's been running for six days now at 5 elephants to the bucket and 100psi which is a little over 3lts/sec  

OK, here's the only pic I've got which might be interesting,


Runner is an ebay purchase from a bloke in Italy. Tried to calculate what size to use but ended up a bit vague so bought two different sizes to try and if I'm not happy with either size I'll just make a different dia. disc and swap the spoons over. The jet is a plastic and rubber waterproof cable gland which adjusts from around 7mm to 16mm. Not sure how well the rubber insert will cope with long term life as a water jet, but it should make it easy to find the ideal jet size and then I'll make a metal one. 28mm copper water pipe and gate valve on an adjustable bracket. Grey tapered pipe and huge blue butterfly valve are bits chopped off a French airport fire engine and welded together. You're going to hate this bit, generator is a 2.2Kw single phase induction motor which came out of a skip. One post on the six post terminal block was blown away, probably a loose connection arcing and some idiot chucked it in a skip for me to find   I'm not certain this motor is going to work properly as a generator as most IMAG info refers to three phase motors, but if it doesn't work out I have quite a collection of other motors to choose from.
What sort of output am I expecting? I've given up trying to work it out and I'm now in 'suck it and see mode' ...
Tried the elephant counting, but I find all the elephants distracting so I use the dull 1000, 2000, 3000 method.

Heinz

[camillitech]

"The jet is a plastic and rubber waterproof cable gland which adjusts from around 7mm to 16mm. Not sure how well the rubber insert will cope with long term life as a water jet, but it should make it easy to find the ideal jet size and then I'll make a metal one."

Pure genius 

"I've given up trying to work it out and I'm now in 'suck it and see mode' ..."

Story of my life 

Cheers, Paul

[Heinz]

I think you should reserve judgement on the pure genius bit untill I see if it works or not  

Heinz

[camillitech]

I think you should reserve judgement on the pure genius bit untill I see if it works or not  

Heinz

Whether it actually works or not Heinz is of no consequence whatsoever. Some of my 'best' ideas have been total flops  I'm thinking of the likes of the self propelled diving 'scooter' to aid picking scallops, powered by a diving cylinder and a pneumatic pistol drill. Total brilliance, well apart from the fact that you couldn't see where you were going for the exhaust bubbles and it only lasted five minutes   

Cheers, Paul

[Justme]

You need some cable pulling lube.

[Heinz]

You need some cable pulling lube.

I tried some talc on the cable which did help a bit, but didn't want to use anything which might screw up the insulation over time. Suppose fairy liquid might have worked? Done now anyway  

H

[Heinz]

Well, the cable gland jet works at least in the short term, bit scary adjusting it with fingers just a few mm from the spinning runner, my hand in the yellow bucket alters the generator RPM and I get very wet.... Set it so the penstock pressure remains constant and the RPM is as high as I can get it judged by the whine pitch.
With 10mins till tea time and a grumpy woman   I made a hasty mains connection to the contactor and tried the turbine out 'live'. I think it works? As a motor with no load it draws 9.9A 745W and with the water on it's 10.8A 550W. I don't really understand why the measured current is higher when it's working as a generator? In fact none of these measurements make sense....  Measured with one of those plug in power meters. How do I tell whether the power is going down the wire or up?

H

[wookey]

You can tell if your meter adds a minus for the negative direction. Otherwise you can't really tell. Measuring AC 'direction' is actually rather tricky without a meter designed for the purpose.

[Heinz]

You can tell if your meter adds a minus for the negative direction. Otherwise you can't really tell. Measuring AC 'direction' is actually rather tricky without a meter designed for the purpose.

The mains meter is an old spinning disc type, so no minus sign. Had a look this morning and with the 'generator' running, the disc is spinning faster, so the generator is still working as a motor. Or do these meters just measure the power going through them regardless of direction?

H

[climber]

Sounds like your generator isn't running fast enough - you really need to find out rpm of motor then measure rpm when water is on. You're not going to generate any power below the synchronous speed of the motor.

[Heinz]

Sound like your generator isn't running fast enough - you really need to find out rpm of motor then measure rpm when water is on. You're not going to generate any power below the synchronous speed of the motor.

RPM with water on and motor switched off is high, switch motor on and the RPM drops a long way.
I took the motor back to the workshop today and hooked up a belt drive from a 1/2hp motor with variable diameter pulley, so I could run the motor/generator above sync. speed to see whether it would generate or not. The motor/gen rpm just drops down to it's normal running rpm when switched on, despite having an extra 1/2hp trying to make it run 300rpm faster. With the motor/gen not connected to the mains and running 1000rpm over speed it only makes 175v.
Decided that this may be a single phase motor quirk, so rather than waste more time on it I'm testing a three phase motor with caps. C - 2C to see if that works OK on the bench, out of time today though....

H

[knighty]

"9.9A 745W and with the water on it's 10.8A 550W"

9.9amps 745watts = 75volts ?

10.8amps 550watts = 51volts ?


I think your readings must be off somewhere ?  what does the plate on the motor say ?

how long is the cable to the motor, and is your plug in power meter at the motor end or the other end of the cable ?

if there's a long cable, there will be a volt drop between one end and the other (mains > motor)... when you start to generate it will change around so the high volt end is at the motor.... I wonder if this could explain some of the problems with the meter readings ?

can you turn the water on slowly at watch the meter at the same time, so you can watch for the meter reading dropping and then rising again ?
(as it needs less power to spin, and then starts to generate power)

[noah]

Motor as generator (IMAG) should give out full power at sync+slip speed. If you have a reversible disc meter it should spin one way when IMAG is running as a motor (and powering your turbine), slow down and stop as sync speed is achieved and go into reverse when generating..
If you connect your IMAG to the turbine with a freewheeling clutch eg

http://simplybearings.co.uk/shop/advanced_search_result.php?sort=2a&search_in_description=0&keywords=sprag&x=0&y=0&gclid=CLbY_eO4qawCFYEZ4QodPWUoAA

you can then start it as a motor and then gradually increase the supply of water to the turbine until it goes into generator mode. You are then in sync with mains all the time.

Of course connecting to grid requires a lot more than just this. check out posts for G83.