Wind Turbine Transmission

[ChrisOlson]

out of curiosity, when you did your rpm vs wattage tests (chart on page 7), did you record the torque required for each output?  if not, do you have any idea of the torque on the generator shaft at given outputs?

No, I did not.  I don't have any good way to do it except maybe with some load cells on the generator stator.

Measuring input torque would be easy.  But I didn't do that either when running the unit on my test bench.
--
Chris

[defed]

was just wondering how much torque the blades were creating at a given rpm.  his dyno tests where he says that he held the tranny at XXX ft lbs @ YYY rpm = ZZZ hp got me wondering what the ft lbs were at during the power curve.  i'm not that great at these power conversions/calcs, so maybe i'm asking in an unclear way.

[ChrisOlson]

was just wondering how much torque the blades were creating at a given rpm.  his dyno tests where he says that he held the tranny at XXX ft lbs @ YYY rpm = ZZZ hp got me wondering what the ft lbs were at during the power curve.  i'm not that great at these power conversions/calcs, so maybe i'm asking in an unclear way.

The torque at the input shaft, in lb-ft can be calculated using the Cp of the rotor at a certain wind speed to figure how many watts it's making, convert that to hp, and apply the SAE hp formula:

HP = torque * rpm / 5252

The RWS 12 foot blades make about 95 lb-ft of torque @ 300 rpm and 28 mph wind speed.
--
Chris

[defed]

thanks Chris.

[cdog]

I thought the hpXtourque 5252rpm was only true with a fixed valve engine, dont the variable valve timing engines go away from this?

[Watt]

dont the variable valve timing engines go away from this?

No

[SparWeb]

I thought the hpXtourque 5252rpm was only true with a fixed valve engine, dont the variable valve timing engines go away from this?

No, it's quite universal.  The torque can be from any source, the equation only talks about the forces in the system, not how the system is built.
... and the equation is older than the SAE, by the way!  

Chris, have you been giving thought to mechanical braking?  I see that back in December, Dan was asking about furling and the shut-down lever, but I was wondering if this was evolving like the rest of the machine?

[ghurd]

Besides being practically impossible for anyone but an extremely sophisticated testing laboratory what possible meaning would such readings have? Seeing as how he already has an rpm vs wattage plot.
I've never seen an input torque/rpm/wattage plot for any wind turbine, direct drive or geared.

Useful for blade design, heat calculations, more?

It's not that complicated.  Quite a few people did it, including Jerry and SparWeb.  Didn't look long, found a couple of SparWeb's with pics and charts,
http://fieldlines.com/board/index.php/topic,138315.0.html
http://fieldlines.com/board/index.php/topic,143680.0.html

[Jon Miller]

First off, not meaning to steer the development of this thread too much backwards but I came across this video on youtube.

http://www.youtube.com/watch?v=8UAgHgSKt3o&feature=related

Seems like the idea has been used all around the world.

Thanks

Jonathan

[fabricator]

Almost every one of those huge utility scale turbines has a transmission in it.

[zvizdic]

This is a professional build transmission with a store available parts so anyone can do the same.
It is not the same as bicycle parts slapped together and pulling out 200W.
It is a wary efficient turbine safe to run in residential areas .

Thanks for sharing again !

[Warrior]

Well, the problem is that us living in third world countries, things cost 3 to 4 times more expensive.

Otherpower sells a set of 24 of the popular 2" x 1" x 0.5" magnets at U$S 300.00. I doubt people would be building direct drive alts if the set of magnets cost U$S 1200.

At these prices, you have to find other ways to do things.

Check out this video (fast forward to 2.23')

http://www.youtube.com/watch?v=DkbZizJvDCI

[zvizdic]

How many KW is making?
It is biiiigggggg.

[fabricator]

This is a professional build transmission with a store available parts so anyone can do the same.
It is not the same as bicycle parts slapped together and pulling out 200W.
It is a wary efficient turbine safe to run in residential areas .

Thanks for sharing again !

It looks pretty crude for a professionaly built machine, for one thing the tail boom is too short by at least 50%, and four blades do not indicate a good understanding of blade efficiency.

[jarrod9155]

I think that thing is a little scary  for me . I'm pretty sure that battery up there controls something important and the wires going to it  just loosely fasten down . In a good wind say 50 mph not sure if I would be around !! But still cool diy .

[ChrisOlson]

Chris, have you been giving thought to mechanical braking?  I see that back in December, Dan was asking about furling and the shut-down lever, but I was wondering if this was evolving like the rest of the machine

Spar, I did at one point think about mechanical braking but decided not to go with it.  The geometry of the furling control mechanism has changed a bit to provide more predictable power control results.  Plus my latest machines have hysteresis braking, using the stator.  The "problem", if you want to call it that, with the GOE222 is that they will refuse to stall even at 2 TSR.  With the wind blowing at 65 mph and 2 TSR, the tip speed is still 130 mph on the blades, which delivers well over 100 amps to a 24 volt bank.

So basically, the furling reduces the swept area which controls power.  The hysteresis braking comes on if the system hits 30 volts and prevents the inverter from kicking out due to over-voltage.  When the stator brake comes on in high winds it usually only clicks in and out 2-3 times, about 1.5 seconds each time, before the powerful gust dies out enough so the side furling is effective.  It applies at 30 volts, releases at 27.  That has worked very well with no more problems with the inverters kicking out.

Using the stator for hysteresis braking on a geared turbine is quite effective because of the mechanical advantage the stator has over the rotor thru the gearing.

I keep shying away from mechanical brakes because they're a wear item.  I think a mechanical brake would be OK for parking the machine, but for power control in very high winds it just wouldn't last.  And even for parking a mechanical brake is not necessary - cranking the tail on the machine and shorting the stator holds it parked even in winds over 60 mph.  And cranking the tail and leaving it run in very high winds limits the power to about 500-600 watts due to all the pressure being gone attempting to steer the rotor back into the wind.

So my end conclusion was that spending the engineering time to add a tail cranking mechanism is much more worthwhile than spending it on a mechanical braking setup.
--
Chris

[ChrisOlson]

This is a professional build transmission with a store available parts so anyone can do the same.
It is not the same as bicycle parts slapped together and pulling out 200W.

One of the main points of my 12G prototype turbine project was to build a simple and efficient step-up transmission that lasts and is maintenance free.  After several thousand hours of flight time in real world conditions I'm pretty happy with the results.
--
Chris

[ghurd]

So basically, the furling reduces the swept area which controls power.  The hysteresis braking comes on if the system hits 30 volts and prevents the inverter from kicking out due to over-voltage. 

It sounds like the dump load system is not up to par.
G.

[zvizdic]

This is a professional build transmission with a store available parts so anyone can do the same.
It is not the same as bicycle parts slapped together and pulling out 200W.
It is a wary efficient turbine safe to run in residential areas .

Thanks for sharing again !

It looks pretty crude for a professionaly built machine, for one thing the tail boom is too short by at least 50%, and four blades do not indicate a good understanding of blade efficiency.

Chris Olsons machine not the other one.Sorry

[fabricator]

This is a professional build transmission with a store available parts so anyone can do the same.
It is not the same as bicycle parts slapped together and pulling out 200W.
It is a wary efficient turbine safe to run in residential areas .

Thanks for sharing again !

It looks pretty crude for a professionaly built machine, for one thing the tail boom is too short by at least 50%, and four blades do not indicate a good understanding of blade efficiency.

Chris Olsons machine not the other one.Sorry

Ahh ok, lost in translation I guess.

[fabricator]

So basically, the furling reduces the swept area which controls power.  The hysteresis braking comes on if the system hits 30 volts and prevents the inverter from kicking out due to over-voltage. 

It sounds like the dump load system is not up to par.
G.

Or, he just has a simple and effective way to limit momentary peak power without adding additional dump loads.

[ChrisOlson]

It sounds like the dump load system is not up to par.

Glen, I no longer really have a "dump load".  We recently put in a 120/240 split-phase inverter.  So we re-wired the water heater 240 volt for better efficiency.  My RD-1 does use the water heater in two stages (using the upper element first, then the lower one) to control voltage on the battery bank.  But once the water heater gets up to 170 degrees the thermostats kick out and water heating as an additional load is no longer available.  I had to do that because I've blown the pop-off valve on it twice due to overheating it.

So I just came up with a different method of voltage regulation that doesn't rely on placing additional load on my system when the water heater gets too hot.
--
Chris

[fixitguy]

Chris im new to all this turbine stuff.been playing with small motors since the end of last year.now i have 1000 watt rig with 8.3 blades on it. it completely fried a 20 amp meter in 20MPH winds which is very rare wind here.so im copying your gearbox design.
i have 2 questions
1..i read your dynamic balance info and you say something like "i found #2 blade to me at fault"...how did you find that?
2..what is the driven and driver # of tooth ?
your wind machine is a work of art.
Paul

[ChrisOlson]

1..i read your dynamic balance info and you say something like "i found #2 blade to me at fault"...how did you find that?
2..what is the driven and driver # of tooth ?
your wind machine is a work of art.

Hi Paul - I static balance the rotor then run it in the shop on a stand with high speed fans blowing on it to turn it at about 60 rpm or so.  I put a piece of masking tape on the back of one blade and with the tail removed and a solid lever on the turbine head I hold on to the lever from behind the machine and watch the blades go around.  A blade that exhibits a dynamic imbalance problem will cause a "pulse" on the lever every time it goes around and I can identify which blade it is, and which way it's "pushing" the lever, by using the blade with masking tape as a reference.

I adjust dynamic imbalance by adjusting tip tracking either fore or aft.

You have to understand the difference between static and dynamic balance.  Static balance involves forces which try to move the rotor in a radial direction.  Dynamic balance involves forces which cause the rotor disc to "wobble".

The prototype 12G machine, and subsequent three after that, had a 28 drive and a 14 driven for a .467:1 ratio.  Serial #0005 and later are using a 30 drive and 14 driven for a .4375:1 ratio.  Different size rotors and/or blade profiles will require a different gear ratio.  I selected the gear ratios I'm using with the 12 foot rotor in order to use a 12 pole generator instead of using 16 poles.  And using the gearing so I can use delta configuration instead of wye without having to use a lot of turns of wire, and at the same time use big wire (13 AWG) one-in-hand.  The delta generator wound with 13 AWG will pretty easily handle 150 amps and 80 sustained without damage to the winding.
--
Chris

[fixitguy]

thanks for the info. i think your work has givin me all i need to get started on mine now.
Paul