motorized furling

[pepa]

Hi folks, do to some medical problems, I have not been able to do any shop work for a while and could only think about what is needed to be done. Very boring work when you don't have anything to think with. Like most of the people on this site, I try to keep up with current post and the problems that are posted along with the good work that is done. I would like for you to look at the project that I came up with and give me your take on the merits of it working or not. Not having the electronic abilities that I would like, I have had to use materials that I have some experience with and that I thought would do the job. I know that there are better ways, but if it works! Item description - automatic furling or yaw. #1 system sets 99% of the time doing nothing until needed. #2 thermostat activates electric circuit to motor when stator starts to overheat #3 motor moves sliding weight on tail boom to lighten tail and cause machine to yaw (very little movement is needed). Weight is stopped by a kill switch. #4 tail furls to yaw windmill until thermostat cools down. Circuit is inactive, tail stays light, circuit needs to be reset... #5 anemometer keeps track of wind direction. #6 thermostat cools and activate a new circuit to move the weight back to its original position. Kill switch stops motor in original position. #7

Circuit is ready for next round of overheating. any help will be welcome thanks, pepa

[DanG]

First though is about using glass-tube reed switches for limit switches, they make some w/ decent current handling and also double-pole... only gotcha would be possible false contact-make if switch specifications do not reject falses when vibrations hit its known resonances...

Simple Tstat would not have parasitic monitoring losses, but on further thought the metals of Tstat left in stator could be subject to heating and losses from flux eddy flows. Might be a valid application for a heat pipe made from glass or plastic.

If active monitoring is wanted how about an IR sensor that reads target temperature through a hole bored into stator and so keeps conductive materials out of rotor footprint while being weather resistant...

[RogerAS]

Pepa,

We all know yo're a busy man, but please oh please make your sketches on unused paper! HA, that's funny.

I took the liberty of dressing up the sketch and setting the type. I have the tiff file I made in photoshop if you want it. If I have something in the text wrong It's cause the background messes with old tired eyes. So I will monitor your comments if I've messed anything up.

I'm not sure I understand, do you plan on using old house thermostats to read the stator temperature?

What is the lower right thing? Is that a bi-directional switch of some kind like a car window switch?

Anyway, if you want this in a tiff hirez file can do. Email me @ above.

[pepa]

hi DanG, thanks for the comment, i was not thinking about the vibration. the bi=metal could be used as part of the contact without using the mercury contacts, because the heat of the stator will make the points move a certain way each time it is heated and is very accurate. some bench test will have to be made to determine the location of switch on stator or bracket. could you give me more details on the valid application for a heat pipe. thanks pepa. Roger. email sent thanks

[ghurd]

A friend of mine just put a weed eater cable on a drag style blade.

It has a lot of friction.

G-

[pepa]

hi ghurd, the switch on the controller can easily be turned with two fingers, there would be very little friction or resistance against the flex shaft, a rigid shaft could be used, but not as easy. thanks pepa.

[harrie]

Hi pepa, I sure hope you get this worked out, it would be great to have something foolproof that you wouldnt have to worry about, It sure seems doable, I think if there was some easy way to pitch the blades, would be good also. Im glad to see there is at least thinking going on about this major problem. Keep up the good work and thanks for the ideas. Harrie

[pepa]

hi harrie, i like your work, i wish my machines came out as nice as yours. i do have some drawings of a dc motor driven pitch control that was moved to a back burner a while back. the system used a flywheel from a 8 hp electric start lawnmower as the dc power supply and blade hub. the circuit was controlled by wireless remote transmitter and receiver from a toy boat. the same system worked very well for a trolling motor that i made wireless remote control, and as the steering on a gas powered outboard for a sailboat. if you would like to see the system, i will locate the drawings and let you look at them. the plans are not complete or tested but should work using this switching system to make it automatic. let me know, pepa.

[maker of toys]

ok, so let me chime in with an opportunity to spend a little money and eliminate a potential headache:

have a look at the datasheet at:

http://www.airpax.net/site/utilities/eliterature/pdfs/Airpax_TSP_5003_0805.pdf

and see if that doesn't neatly solve the temperature monitoring problem. . . of course, $20 or so per switch could be a little off-putting for those who have a tight budget.

I've used these to protect BIG (~100kw continuous input, watercooled) electromagnets.  Granted, my application is DC . . .  but I've also seen these switches in all manner of  power supplies, motor drives, MOTORS,  and the like, serving as overtemperature interlocks.  they work and they don't take much space.  they're not inherently  watertight, so I'd tape mine up (to keep resin out) and submerge it in the stator casting. they're rated pretty generously, unlike the contacts in a thermostat. . . .

because they're small (circa 1cm or 3/8" diameter on the sense element), the potential for eddy current heating and other troubles is down from what a re-purposed home thermostat might experience.

Just a thought.

(I'm actually planning to scatter a couple of integrated circuit temp sensors in my castings. . . but there's a lot more that has to happen in the feedback path between sensor and mill if you go that route. I might put one of these in as a failsafe. . . . one of these days i'm gonna have to leave off planning and start building. . . .)

-Dan

[pepa]

Hi Dan, the part works great, does this switch work both ways or do I need two switches to activate the two circuits, #1 hi temp #2 low temps. I could not see how it would work both ways from the speck sheet( don't know what I am looking at) I need to activate one circuit at the time from the same electrical supply line. Any help would be great thanks,  pepa

The petter with the new shaft extension

[SamoaPower]

Pepa,

Wouldn't something like this be a lot simpler?

[harrie]

Yes, I would be interested in seeing the drawings, but I am a little worried about posting my e-mail, last time I did, I got thousands of spams. I have sence changed it.

[harrie]

Somoapower, what is that?? If you had it posted before, I missed it.

[ghurd]

It needs to be unreadable to 'spam-bots'.

Maybe write it out... 'me at aol dot com'

Or 'my aol email is me'

Works for me, so far.  Fingers crossed.

I've seen people hand write their email, scan or photograph it, then post a jpg.

G-

[DanG]

The link for smaller temperature switches point to some nice ones though I would only ring the outside of stator to keep them from under working flux loops. I was not thinking of using mercury anything, just reed switches with current limited control voltages.

Also want to add a note cold temperatures force the reeds to become more sensitive to magnetic fields just at the same time as magnets become more powerful from contraction. If used as a stop-position sensor under coldest temperatures it could 'make' 2 or 3cm before hot weather 'make' so its not super precise.

A heat pipe is a thermo-siphon using a tube within a tube, hot flows outside and cool returns in the inner tube. Copper is material of choice usually but that is for rapid reaction timing. Most likely over complicating things I admit!

Just now I wondered if there could be an arc-sensor circuit available that we could modify to be able to flag when a coil is developing an internal short. Newer home circuit breakers now can see arcs on the line...

[pepa]

hi samoapower, i have been following your sight but you slipped that one past me. tell me a little about the design and the motorized yaw. i built one downwind model for a sailboat and used a dc motor with pvc blades,( my first windmill). most people here use the upwind design and that is what i was trying to fit my system to. i like to have a system do as many different jobs as it can, a bonus of the moving tail weight is being able to adjust the windmill as it is working under normal conditions. a ground level switch added to the circuit would bipass the tstat and allow you to set the tail for best operation and also shut the machine down at any time in a safe mannor. i've seen several post where the tail needed to be adjusted after it was raised, several of mine too. post something on the down wind. thanks pepa.

[pepa]

Dan, that is the great thing about this site, having so much different type knowledge in one place. the arc-sensor sounds like what we need. the stop switches can be any cheap always on type contact switch like microwave oven lites use, i have dozens of them. thanks pepa

[pepa]

harrie, email me at suesminis at hotmail dot com pepa

[SamoaPower]

harrie and pepa,

This is a quick throw-together test set-up for experimenting with controlled yaw. See:

http://www.fieldlines.com/story/2006/6/26/12214/2424

I think I deserve a KISS merit badge for this one, it took all of 20 minutes to put together using an Ametek. The yaw motor is a ham antenna rotator.

With controlled yaw, no tail feathers are needed and you have free choice of upwind or downwind. I prefer downwind for blade proximity issues.

I'm convinced enough of the merits of controlled yaw that I'm committed to using it on the 16 footer under construction.

[maker of toys]

now that is one BUSY engine.  <G> Glad to see that everything fit up right!

the temperature switches I linked to are single acting.  you could use one to pull in a relay (preferably a low current one-  see datasheet note about low current contacts) and the relay would hold the mechanism in the 'overheated' state until the tempswitch dropped out again. the relay would then relax, and everything would drop back into generation mode.

MY preference would be to introduce some hysteresis into the system by makeing the switch that controls the 'return to generate' behavior operate at a lower temperature than the 'overtemp' switch. . . . by doing that, you lengthen the time intervals between tripping into furl. . . reducing wear on the moving parts and saving power.  (having the two switches would also eliminate the parasitic draw of the relay while the machine was furled, while bouncing on the temp-switch would suck down amps to run the mechanism.)

I would (being me) probably have a pic or some sort of asyncronous discrete logic counting the furls-per-day or some such. . . and if the thing tripped into 'thermo-furl' more than, say, 3 times in one day-night cycle, have the mill stay furled and signal the human element to have a look at the equipment.  hopefully, that would catch any serious wrongness before the mill got to the shedding parts stage of self-destruction. (a 1/4lb magnet falling from 60 ft would raise a welt. . .)

. . . thinking about the form of a 'fault sensor' . . . .

-Dan

[pepa]

Dan, the original function for the diesel engine was to turn one blower fan blade and the timer for firing the coil. i thought this was a waiste of usable power for this size machine. i designed each addition so that it can be quickly disconnected, by removing a drive belt. the main feature i wanted from this unit is charging batteries as a backup motor. i have a unending supply of clean vegitable oil and with the different options on this unit, i will be well covered in any power outage. also with the whole thing built as a trailor with a 20gal tank, i can take it anywhere power or heat is needed. i also have room for another option on the original shaft with some minor adjustments. you can tell i love my petter. the boiler to burn untreaded vegy oil will have these same features (except mobility) plus a lot more and should put me completely off grid when finished but, i wont disconnect completely because of my health and leaving my wife to run all this equipment by herself. everything that i am doing will be waisted unless i post as i go to let others have the oppertunity to use it, if they choose to. thermo-furl, i like that and would like to use it if you dont mind. if you or some of the other folks can help with the electrical, i will build this system into my new machine and post the results. thanks pepa.

[Darren73]

Pepa,

probably your easiest option for the overload detection would be a motor overload unit for a 3 phase motor, these have the option of manual or automatic reset and contacts out that you could use to drive your tail weight.

regards

Darren

[pepa]

great info Darren, i have a motor shop close to the house, i will stop in to see of i can locate the part. thanks pepa.

[jmk]

 Samoa, that was an interesting post. How well does it track the wind? Can it move with the wind, or does it all have to be controled by the gear motor?  

[harrie]

Ok, now I remember, I just didnt see the picture before. I think without a tail, one should still try and equal the weight over the tower, using a shaft with weights to equal the weight of the turbine. I think it would be easier on the yaw bearings.

[SamoaPower]

jmk,

The idea with controlled yaw is that you don't want it to flail around by the wind directly. It only turns by the rotator. The rotator controller receives wind direction data from the site anemometer/wind vane. After averaging, it turns the rotator to the average wind direction. This way, turbulent gusts are averaged out and the seeking is a lot more gentle.

I've found very little difference in output power with 30 degree wind offsets so, quick wind direction tracking is not necessary or desirable.

[SamoaPower]

harrie,

Yaw bearings in this case are in the rotator and are about 8 inches in diameter. They handle an offset vertical load pretty well.

Ideally, you're right, of course.

[jmk]

 Plus, when the turbine in turbulant conditions wipes out at the end of the gust. The rotor over powers the tail and causes it to turn away from the relitive wind. causing it to have to turn back and forth. So you would gain by staying turned into the wind in these conditions. Of course, if the turbine was at the corect hieght it wouldn't seek, it would stay with the prevailing wind. Not everyone can get that high though. I like the idea. It would work better I think in turbulace than the conventional tail.