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Update on Lighthouse Sculpture
By Aaron, Section Wind Posted on Mon Dec 26th, 2005 at 03:36:28 AM MST
plus new PVC blades for dual axial flux genny

a couple of months ago i submitted a posting on my sculpture Lighthouse.
http://www.fieldlines.com/story/2005/9/27/15317/0994
i was not able to get much voltage from my tape drive motor except in high wind.(even after gearing it up). WELL........i fixed that problem. now i have a stepper rated at 120v 70RPM. it really cranks out the juice. in low wind its usually putting out around 10-25 volts ac and max is about 100vac. it can easily be converted to dc with a bridge rectifyer. turning it slowly will light 3 mr-16 LED fixtures very easily without any noticable load. i don't want to charge batteries but just to light up some lights when the thing is spinning. i found a LUXEON fixture which runs on 12-28 volts.
does anyone know of something i can buy, convert or make easily which would allow in 0-28 volts and block the rest? there must be something like that out there. here are some photos of the new set-up.

and here is a traditional wind alternator almost finished. i bought hugh piggott's plans and they are great. dual axial, 3-phase, 12 wedge magnets, 9 coils of #11 wire 40 turns, 7 foot PVC prop. we'll see what happens, so far looks like its going to have to spin pretty fast to come up with 12vols.

Update on Lighthouse Sculpture | 15 comments (15 topical, 0 editorial)

Re: Update on Lighthouse Sculpture (3.00 / 0) (#1)
by richhagen (richhagen (a t) Juno.com) on Mon Dec 26th, 2005 at 12:11:54 AM MST
(User Info)

One simple shunt regulator idea would be to place a battery of strings of zener diodes in parallel, each diode in series with a small value resistor. If you pick about 25 volt zeners rated at .5 watts, then from power = current times voltage, at .5 watts, the current would be 20 milliamps. If you couple this with a 150 ohm resistor, then it will reach 28 volts across the two in series at approximately 28 volts while soaking up 20 milliamps. It will conduct essentially no current below 25 volts. Connect as many of these strings as necessary in parallel to soak up more than the maximum possible power generated during the worst gale by your stepper. Realize that this simple circuit is simply converting the surplus energy to heat starting at 25 volts, so don't insulate it and allow for cooling. When the alterator starts to spin faster than what would be required to produce 25 volts, it would start to become stiffer, the belt assembly will have to handle the stress of a high wind situation as the motor will become extremely hard to turn at higher rpm as you exceed 25 volts.

Here I see someone has 28 volt zeners, .5 watt, a hundred pack for $3.50 US
http://cgi.ebay.com/100pcs-1N5255B-28-VOLT-0-5-WATT-ZENER_W0QQitemZ7574878487QQcategoryZ7287QQrdZ1QQ cmdZViewItem
Of course when you add a little resistance, the voltage will go up a bit higher.

Of course, since LED's are so cheap, one could make the same sort of thing with a huge number of leds, the byproduct would be a mixture of light and heat then, and could give an interesting effect to the sculpture in a gust of wind at night. Simply hook enough LED's in series so that they will not conduct until the voltage reaches a threshold value, and then add a small resistance in series as with the LED string, then parallel many of these strings together so that the current handling ability far exceeds that of the generator.

For my little 'toy' stepper mill: http://www.fieldlines.com/story/2005/4/8/31534/30936
I essentially do this, the regulating LED's in that case are the only load up to about 3.9 volts when some zener diodes start conducting. It would simply take more power than the generator can produce to blow the zeners. yet the led's light up when the blades spin up in the wind. You will have a voltage drop across the leads from the stepper to the LED's in you system, as the copper wires have some resistance and function exactly as a small value resistor in the circuit. There's probably too much resistance in the power line from my little stepper to hold down the rpms of the alternator on that one, but if I hooked up a thicker cable and more strings of LED's in parallel it would to a greater extent although the stepper doesn't do this nearly as well as a dual rotor axial flux alternator does (they stop with a bang and an arc like a welder when you short the leads and become incredibly stiff to turn).

Since it is a VAWT I'm guessing that overspeeding is generally not a problem even open circuit, so having a relay that opens the circuit to the LED's above a certain voltage, with a coil/resistance circuit that can handle the highest voltage output of the alternator in the worst gale might be an option. Even two in series in case of a failure in one might not be bad to protect the LEDs.

Rich Hagen
'A Joule saved is a Joule made'

Re: Update on Lighthouse Sculpture (3.00 / 0) (#2)
by finnsawyer on Mon Dec 26th, 2005 at 09:01:31 AM MST
(User Info)

Since each Zener diode guarantees a set voltage, he could split each resistor into a resistor in series with another resistor in parallel with an LED and have the LEDs light up in sequence as wind speed increases (as succeeding Zeners conduct).
GeoM
[ Parent ]

Re: Update on Lighthouse Sculpture (3.00 / 0) (#3)
by electrondady1 on Mon Dec 26th, 2005 at 09:36:19 AM MST
(User Info)

wow, when you guys finish with Aarons light house (congratulations Aaron) could you swing north and help me with a baseboard heater?

[ Parent ]

Re: Update on Lighthouse Sculpture (3.00 / 0) (#4)
by finnsawyer on Mon Dec 26th, 2005 at 10:08:50 AM MST
(User Info)

North where? I'm at 47 degrees north latitude.
GeoM
[ Parent ]

Re: Update on Lighthouse Sculpture (3.00 / 0) (#7)
by electrondady1 on Mon Dec 26th, 2005 at 05:06:07 PM MST
(User Info)

ok, come almost due east. don't get your feet wet in lake michigan.and you'll need a boat for lake huron! i'm at about 44.4 deg n.lat. and and 80 deg. longatude. west of greenwich. no sun block required. but bring a warm coat! diodes i understand but i'm just starting to come to grips with the function of capacitors and there possible use in a batteryless heating system .also , the effects on voltage from resistors also, transistors etc, etc, a battery of strings of zener diodes in parallel, each diode in series with a small value resistor. anyone wanna' sketch that out!!! split each resistor into a resistor in series with another resistor in parallel with an LED and have the LEDs light up in sequence as wind speed increases (as succeeding Zeners conduct). oh yea, ive got a lot of reading to do!!

[ Parent ]

Re: Update on Lighthouse Sculpture (3.00 / 0) (#11)
by finnsawyer on Tue Dec 27th, 2005 at 09:26:15 AM MST
(User Info)

Well, good luck. You can probably compress the time needed by getting a book on basic circuit theory. Another possibility would be to enroll in an electronics course at a nearby college. Considering those courses usually have labs, you might enjoy it. As far as drawing the circuit, not so easy to do. Nobody seems to have thought of producing a program to make it easy to do. I made such a program in the days of the Commodore 64, but Bill Gates made his Windows System too hard to work with.

More specifically, I live a mile from Lake Superior just west of the Portage Shipping Canal.
GeoM
[ Parent ]

Re: Update on Lighthouse Sculpture (3.00 / 0) (#5)
by Aaron on Mon Dec 26th, 2005 at 10:47:45 AM MST
(User Info)

thanks for the imput guys. rich, i bought the zeners.
"Since it is a VAWT I'm guessing that overspeeding is generally not a problem even open circuit, so having a relay that opens the circuit to the LED's above a certain voltage, with a coil/resistance circuit that can handle the highest voltage output of the alternator in the worst gale might be an option. Even two in series in case of a failure in one might not be bad to protect the LEDs."
this sounds like a good idea but i'm a little unclear...is this a different option than utilizing the zeners? the propblem is i need to let ALL voltages in before the max. voltage of 28. for instance, if the wind is barely moving my prop it will put out 12volts and therefore light the LEDs. i want it to light up with little movement. ideally, it would get brighter and brighter as the prop spun faster. any ideas?
thanks, aaron www.apvsculpture.com

Re: Update on Lighthouse Sculpture (3.00 / 0) (#6)
by richhagen (richhagen (a t) Juno.com) on Mon Dec 26th, 2005 at 04:45:45 PM MST
(User Info)

The zeners will not conduct any noticable current until their threshold voltage is crossed. If you connect a few leds in series with resistance such that they will not exceed there maximum rated current below the maximum system voltage, then they will begin to glow once the voltage of the stepper exceeds the voltage drop across the diode or diodes for them to conduct. They would glow brighter as the voltage from the stepper increases. The zeners would then function as a shunt and allow lots of current to flow once the voltage increases past their rated value, the purpose being to prevent the system voltage from rising too far. You could have lots of fun with the design of the lighting. Leds begin to conduct at different voltages. This voltage is usually similar for similar colors, because the light given off by the led is of a particular frequency or energy, and the electrons flowing through the LED need to impart this energy to the photons.

Red LED's usually start to emit light when 1.2 volts or more is across their leads. Yellow Led's require slightly more voltage, Green LED's about 2.5 - 3 volts, blue and white LED's which are basically blue or ultraviolet leds with a phosphor begin to conduct a bright light from about 3 volts.

If you connect one red LED in series with a resistor, it will begin to glow at about 1.2 volts and will become brighter as the voltage increases. If the LED can handle 25 milliamps, and you size the resistor for a maximum voltage of 28 volts, then it would be (28 - 1.2)volts = .025 amps * (resistor value in ohms) which is equal to 1072 Ohms. The power turned into heat in the resistor in watts is equal to the current in amps multiplied by the voltage drop in volts. So it would be .025 Amps * (28-1.2)volts = .67 watts. Use a 1200 Ohm 1 Watt resistor for a bit of a safety margin.

If you connected two in series with a resistor, then it would begin to conduct when the some of the forward voltage drops across each diode is reached (1.2 + 1.2) = 3.4
The value of the resistor would then be (28 - 2.8)volts = .025 Amps * (resistor value in ohms) and solving for the resistor value we obtain 1024 ohms, so a 1200 ohm resistor at one watt would work here as well.

As you may already have guessed, if you connect more LED's in series, you will be turning a larger percentage of the energy into light in the LED's and a lower percentage of it into heat in the resistor.

You could make a star that gets bigger when the wind increases, or a simple bar graph that grows and changes color as the wind increases, or any of countless other effects.

The relay was a second idea for a control scheme, the relay coil could be hooked across a voltage divider circuit from the output of the alternator, or connected through an appropriate zener diode or several normal diodes to adjust the voltage the coil sees relative to the output of the alternator. That way the relay could be operated in a normally closed mode such that when the output voltage of the alternator exceeds a certain amount, the relay would open to protect the circuits attached from receiving too high of a voltage. You couldn't use this with a horizontal axis machine as once the electrical load was removed from the mill, the blades would speed up to point where the wind turbine might be torn apart from the forces, throwing a blade or two. With a vertical axis machine I do not think that that would be a problem.

Rich Hagen
'A Joule saved is a Joule made'
[ Parent ]

Re: Update on Lighthouse Sculpture (3.00 / 0) (#8)
by electrondady1 on Mon Dec 26th, 2005 at 05:17:18 PM MST
(User Info)

wow, again !! i'm gonna' have to file this post & read that ten times.cool

[ Parent ]

Re: Update on Lighthouse Sculpture (3.00 / 0) (#9)
by Aaron on Mon Dec 26th, 2005 at 06:04:10 PM MST
(User Info)

wow is right, looks like i better go back to school for electronics before i finish this one. thanks rich, i'll also be filing this for rereading.
thanks for the direction,
aaron

Re: Update on Lighthouse Sculpture (3.00 / 0) (#10)
by Dave B on Mon Dec 26th, 2005 at 11:17:58 PM MST
(User Info) http://www.madbbs.com/users/bruggelog

Hi, Rich & Aaron,
A very easy way to build an LED bargraph or dot meter is with the LM3914 IC. I am using this to trigger my solid state relays (for a vaiable load controller using hot water heating elements) at any selected voltage indicated by a "lit" LED. I also have a potentiometer on the DC input to set the meter level to start at basically any voltage which then is linear throughout the range. I have 2 IC's which sequence 15 LEDS, first 5 green, 5 yellow, 5 red. Just thought it might be something for you to check out. Here's a link http://www.uoguelph.ca/~antoon/gadgets/lm3914.htm If that doesn't work just google search LM3914. Good luck with your projects, it looks great. Dave B.

[ Parent ]

Re: Update on Lighthouse Sculpture (3.00 / 0) (#12)
by Aaron on Tue Dec 27th, 2005 at 05:04:00 PM MST
(User Info)

thanks dave b. i will look into this option. so much to learn.....
aaron

[ Parent ]

Re: Update on Lighthouse Sculpture (3.00 / 0) (#13)
by zap (bell47g5a at comcast dot net) on Tue Dec 27th, 2005 at 07:41:04 PM MST
(User Info)

Aaron could you post more specs on the stepper motor or better yet another photo of just the name plate? Thanks,

zap

Re: Update on Lighthouse Sculpture (3.00 / 0) (#14)
by Aaron on Wed Dec 28th, 2005 at 11:00:18 AM MST
(User Info)

zap, the plate is worn and you can't really read it all. basically, its rated @ 120 volts and 70 rpms. i think this type of stepper is readily available.
aaron

[ Parent ]

Re: Update on Lighthouse Sculpture (3.00 / 0) (#15)
by zap (bell47g5a at comcast dot net) on Wed Dec 28th, 2005 at 09:44:23 PM MST
(User Info)

Thanks Aaron, I had tried a few google searches, i.e. stepper 120 volt, and stepper motor 120 70 rpm, and variations of all of those and just never was able to find a stepper with your specs and that's why I asked for the pic. I shall continue the search.

zap
[ Parent ]

Update on Lighthouse Sculpture | 15 comments (15 topical, 0 editorial)

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