Cheap chinese horizontal wind turbine, an in depth exploration.

[Porch]

Sorry I have been MIA, life gets in the way sometimes. Please excuse me if I am rehashing something that was posted.

4 12v 5 watt lights in series, makes for a 48v light at 20 watts. (see note below)

The wind generator should be connected to the rectifier, the output of the rectifier should be connected to the cap (mind the polarity), and the caps connected to the string of 4 light bulbs. So the negative from the rectifier will connect to the negative of the cap (pin next to the stripe), and then two one end of the lights (they do not care what end). Another wire connected to the positive of the rectifier, the other pin of the cap, and to the other side of the string of lights.

I believe you have two meters. The Fluke T5 does not do DC amps, so we will use that for our DC volts measurement, the other meter does DC amps, so we will use that for the amps measurement.

Put your Fluke meter on DC volts, and connect to the positive and negative wires, at any point it's convenient. It can be at the cap, or at the rectifier.
Now set your other meter to DC amps, 10 amp scale, move the meter leads, and connect it in series in the circuit. Aka, replace one of the wires going from the rectifier to the cap with the meter leads. Or cap to the string of light bulbs, it does not matter.

Spin the wind generator with the drill. Start slowly and watch the voltage on the meter. Try to get it up to about 62v, as that is as high as it would need to go to equalize a LA battery bank, giving the generator the best shot at making the most power it can. Make a note of the amp reading you are seeing on the DC amps meter while the voltage is at 62V. The string of 4 lights should glow very brightly since they will be seeing 15.5v each.

Your watts is the volts reading, times amps reading. So if you get it to 62V, and you see 2.5 amps on the meter, the watts generated is 155 watts. 62 times 2.5 = 155.

Now you can change the load, in this case, a series of 4 12V lights, to any load you want. You can use 4 12v 20 watt lights. The goal is to spin the generator up to about 62V, and take an amp reading. You can even spin it up to just 48V and take an amp reading then, but it may produce more power at the higher voltages, so that is one reason I picked 62V.

Note that as others have pointed out, that incandescent light bulbs are really the wrong choice for a load. They draw a lot of power when cold, far more then their rated wattage. So the wind generator has to generate enough power to get the light warmed up. So this test works and gives accurate wattage numbers, assuming the light bulb is small enough that the generator can get it warmed up and up to brightness. So this test is not a good way to see the peak power the wind generator can make. For that, we need a different load.
However, this is a good test for a hobbyist to play around with without the risk of blowing an expensive tester up.

 

[Hedges]

Make sure your volt meter, the clamp one, is set to DC volts. It might be set to AC. Hard to tell from the pic. Your amp meter looks to be set to a 20m or 200m amps. It needs to be set to the 20 amp scale.

Oops, the clamp meter reads volts, and the other is series-connected for amps?
Good thing I qualified my opinion has "humble".

updated scale settings to 20amp
14.5 Vdc (confirmed)
0.39 Adc
same load
same rpm
I am sad

But my reality-check judgement was correct.
So you can get 5.66W not 67W from a 5W bulb - who knew?

Time for two bulbs in series, and increase RPM.

Automotive alternators will run more like 3600 RPM. This one probably has more poles, and is intended to work at low RPM.

 

[Porch]

Automotive alternators will run more like 3600 RPM. This one probably has more poles, and is intended to work at low RPM.

Alternators run higher then that as they are driven faster then engine RPM. But that problem can be solved somewhat with a pulley and cogged belt.

 

[brandnewb]

LOL, my very first arc (tiny bolt of lightning) when touching one of the caps. I felt nothing but I did loose a couple of years of expected lifespan due to emotional shock. Yeah I am laughing now but rest assured I was not when it happened.

i'll have to order a soldering station, as I have been informed about prior, as I can't reliably clamp on an alligator clip. I'll keep you guys updated once it arrives.

I did already buy that kindle wind turbine cook book. We might need it if this particular alternator turns out to be crap.

 

[brandnewb]

That's probably at least close.
But I'm unsure about your 3 phases with 5kW setting, which would only be one resistor connected (somehow) to two leads.
I would think 5^2 / 23 = 1.09W

Have you measured resistance? 23 ohms was my calculation.

Did you observe generator was dragged down considerably?
There would be some RPM that optimally harvests power at a given wind speed.
Hydro is simpler, given constant water feed, so fixed load rather than MPPT could be used.
Wind with simple rectifier into battery, no load until RPM produces voltage above battery, so can be somewhat reasonably tuned.

not yet, and I am also willing to disconnect the fan if I can figure out how

currently I am learning about how to deal with capacitors in a safe manner. All theory for now as I am still in the process of ordering a soldering station

 

[brandnewb]

They do see to be doing a good job keeping the birds off the roof.

lol

 

[Porch]

not yet, and I am also willing to disconnect the fan if I can figure out how

currently I am learning about how to deal with capacitors in a safe manner. All theory for now as I am still in the process of ordering a soldering station

Capacitors are just small batteries. They don't hold much of a charge, but can be discharged and charged many times per second without harm.
If you have it wired how I stated, the light is across the cap (connected in parallel), so once you stop spinning the turbine, the input power will stop and the light will quickly drain out the power from the cap.

The cap has little prongs on the top, you should be able to clamp on a wire like how you are doing everything else.

 

[Hedges]

Capacitors store energy, and above some threshold can be dangerous to human life.
The article below says 5 Joules. I've seen 1 J to 10 J used by some organizations for safety rules.
Energy stored in a capacitor J = 1/2 C V^2
If you had a 100 uF capacitor charged to 100VDC,

1/2 x 100e-6 x 100^2 = 0.5 joules

For a given capacitor, you can calculate what voltage would make it hazardous. Keep it below 1 J and it should only startle but not kill you.
(Just don't fall into spinning turbine blades when you get shocked. Mechanical energy also has levels considered hazardous.)

We have some capacitors at work which would be hazardous if charged to their rated voltage (700V) but not as we are presently using them (48V)

Electrical Safety in Research Operations

www.ehss.vt.edu

 

[Porch]

Capacitors store energy, and above some threshold can be dangerous to human life.
The article below says 5 Joules. I've seen 1 J to 10 J used by some organizations for safety rules.
Energy stored in a capacitor J = 1/2 C V^2
If you had a 100 uF capacitor charged to 100VDC,

1/2 x 100e-6 x 100^2 = 0.5 joules

For a given capacitor, you can calculate what voltage would make it hazardous. Keep it below 1 J and it should only startle but not kill you.
(Just don't fall into spinning turbine blades when you get shocked. Mechanical energy also has levels considered hazardous.)

We have some capacitors at work which would be hazardous if charged to their rated voltage (700V) but not as we are presently using them (48V)

Electrical Safety in Research Operations

www.ehss.vt.edu

Very good numbers. But the threshold is also the conductivity of the human skin and (that can change changes). A 1.5V AA cell does have the potential to kill you in amps, but the voltage is so low, it can't deliver the the amps to your body. So we don't worry about any protection when touching the terminals with human skin under any conditions.

But I might get banned in another thread for stating this, so good luck you all and have fun if you don't see me again.

 

[Hedges]

For safety we have a voltage limit, a current limit, an energy limit.
So a massive supercapacitor with 1.5V won't be a shock hazard.
A 12V car battery can release dangerous energy, e.g. melt a wedding band.

The purpose of the 1J or 10J limit isn't to state that above that is definitely hazardous. Rather, below that is not harmful to human life.
So we do the math, and if above the sure-safe limit we need to sharpen our pencils or mitigate the hazard.

Mechanical energy, compressed gas, chemical energy, electricity ... all possible hazards and part of my safety training.
As an example, you could lock out power to a ventilation system before working on it. But if wind gets a fan turning, that could be a safety risk. Need to consider that and secure the fan against turning if you could get in its way.

 

[Porch]

For safety we have a voltage limit, a current limit, an energy limit.
So a massive supercapacitor with 1.5V won't be a shock hazard.
A 12V car battery can release dangerous energy, e.g. melt a wedding band.

The purpose of the 1J or 10J limit isn't to state that above that is definitely hazardous. Rather, below that is not harmful to human life.
So we do the math, and if above the sure-safe limit we need to sharpen our pencils or mitigate the hazard.

Mechanical energy, compressed gas, chemical energy, electricity ... all possible hazards and part of my safety training.
As an example, you could lock out power to a ventilation system before working on it. But if wind gets a fan turning, that could be a safety risk. Need to consider that and secure the fan against turning if you could get in its way.

Ah, I see now. The Joules standard is not just shock, but reaction to other influences, as in shorts. Good thinking. Does it also cover physical damage as in a cell phone battery getting ruptured?

As to the testing on the generator. I have been informed by the moderator that "ANY dc voltage can kill" and to play it safe under all circumstances. I will have to refrain from helping out in any more testing. I highly suggest brandnewb watch some videos on basic electronics, study up, and ask his questions on electronics related forms. The EEVBlog is a good one.

 

[Hedges]

The Joules limit would be for capacitors and inductors which can release their stored energy in a short time and possibly kill by stopping the heart (shock).
A battery would have many more joules (one Joule is 1 amp at 1 volt for one second), but has a voltage limit.
The battery can be a burn or fire hazard, and a chemical hazard.
I think it takes many more joules to be a hazard for burns (like heating a wire, or splattering one into plasma).

The generator has way more than a couple joules stored as mechanical energy, and can release it as voltage and current probably above the hazardous voltage level.
If windings are shorted and carrying current, then suddenly opened, they will produce a higher voltage from their inductance. The energy stored in magnetic field would be a hazard if more than a joule or so.

It is best to set this stuff up with no power applied, then apply electric or mechanical power and read meters without handling wires. Then disconnect power or let rotation stop before handling.

Same goes for our PV systems. Disconnect battery, grid, PV panels and verify zero voltage (allow capacitors to discharge too) before working on circuit.

 

[brandnewb]

For a given capacitor, you can calculate what voltage would make it hazardous. Keep it below 1 J and it should only startle but not kill you.
(Just don't fall into spinning turbine blades when you get shocked. Mechanical energy also has levels considered hazardous.)

LOL

 

[brandnewb]

But I might get banned in another thread for stating this, so good luck you all and have fun if you don't see me again.

I think everyone, even the newcomers, here are smart enough to take their own responsibility. But stick around please. You will be missed when you do go.

 

[brandnewb]

I will have some results ready in a bit. I did not want to wait any longer on a soldering station.

 

[brandnewb]

load: 4 x 12v5w in series
caps in cuircuit: x 2
rpm +-320
Vdc: 21
Adc: 0.22
THe light bulbs did light up but not so brightly.

My god tinkering takes a lot of time, especially when one does not know what they are doing.
Had my second arc today. This time I lost no lifespan as I actually saw it coming/expected it.

 

[brandnewb]

Byw guys, I'll gladly go the extra distance and expose the makeup of this alternator. Or possibly first do some more experiments if you guys might find that interesting data.
I am not sure but for now I believe we can't expect it to do something useful at safe speeds anyway can we? I might as well disassemble it.

Also I will be creating a new thread about my winding my own alternator after I have read that kindle cook book but I am dyslectic on a whole other level so that will take me a few seconds.. ehh weeks to get through.

 

[brandnewb]

I still very much believe, not having read that kindle yet so I might be way off, that for an alternator to do something usefull at low rpm one needs to increase the diameter by alot. Have much more poles and much more coild groups. theneven at slow speeds the outer part of the rotatory is spinning quite fast already.

Ok sure it will possibly present new problems that even with a mild storm one can fry chicken on the turbine. But that is a problem I'll solve somewhere down the road

 

[brandnewb]

I will have to refrain from helping out in any more testing

Under my own responsibility I highly am in demand of any type of advice including yours. Let this be a warning to all viewers that electrics are dangerous under any circumstance. And playing with it is at ones own risk even though following tips and tricks of others. We are on our own in terms of responsibility is my stance on this.
But sure we can double up on safety aspects. For example like I did now. I make sure to insulate all and everything. This could be like a standards warning in the forum software

 

[brandnewb]

Also, I will promise to get thick rubber gloves that still allow for dexterity and fine control

 

[brandnewb]

I have asked for a move of this thread to a more serious, less newb friendly sub topic. Everyone there should know things can get out of hand.

Why This Subforum Exists.

I asked Will to create this subforum so we could discuss real world and theoretical issues that may not be code compliant and will probably violate manufacturers warranty. I also hope for spirited discussions without anybody getting hurt feelings. It's ok to disagree I hope to advance knowledge...

diysolarforum.com

 

[Hedges]

load: 4 x 12v5w in series
caps in cuircuit: x 2
rpm +-320
Vdc: 21
Adc: 0.22
THe light bulbs did light up but not so brightly.

4.62W, similar to before (5.66W).
95.5 ohms for 4 in series (23.9 ohms each) vs. 37.2 ohms for one.
Because filament didn't get so hot, it was lower resistance.

21V vs. 14.5V, 50% higher, and power was slightly less.

320 RPM isn't terribly fast.
Examine slope of blade (vs. circumference where measured) and estimate wind speed.
You're going to have to spin much faster to get higher voltage and current at that voltage.

AC motors are typically 3600 RPM at 60 Hz, half that if they have twice as many poles.
Yours probably has many more poles.
Up to about 1000 Hz, silicon rectifiers work OK (400 Hz is common for airborne applications to save weight of magnetic cores.) Above 1000 Hz, the rectifiers don't turn off fast enough and conduct for a while in reverse direction.

 

[Hedges]

LOL

A capacitor after the rectifier will store energy after turbine stops.
By placing a resistor in parallel, it will discharge after time. With an LED in series, it will light up when voltage is present. Resistor value might be selected for 10 mA through LED. Lower resistance higher wattage in parallel if that is too slow to discharge.

A resistor sized for 1W at operating voltage would drain 10J on the order of 10 seconds (exponential decay, so takes longer.)
It will also dissipate 1W the entire time it is powered by generator. If you pick a resistor rated for intended wattage, it will get hot enough to burn your finger (maybe 100 to 150 degrees C). If you connected eight 1/8W resistors in series with total value selected for about 1/4W dissipation it should only have 35 degrees rise to about 55 or 65 degrees, still rather hot to the touch.

 

[brandnewb]

A capacitor after the rectifier will store energy after turbine stops.

I am not sure I understand. Did you mean to say it stores energy while the alternator generates but keeps releasing power until empty?
If that is not what you means I have to go back to the drawing board again as then I still am missing a lot of finer concepts.
Anyway, maxmimum respect for your input

 

[Hedges]

I am not sure I understand. Did you mean to say it stores energy while the alternator generates but keeps releasing power until empty?
If that is not what you means I have to go back to the drawing board again as then I still am missing a lot of finer concepts.
Anyway, maxmimum respect for your input

Yes.

While generator is turning (fast enough to have higher peak AC voltage than voltage in capacitor), current will flow from generator through diodes into capacitor.

When generator stops, charge will remain in capacitor until it has drained, either due to self-discharge, reverse leakage of diodes, or a load you connect. The 10 Meg ohm input of a volt meter will drain it slowly. It is common to connect a resistor to drain capacitors, probably required in most products which store hazardous energy. Old CRT television sets are particularly known for being a shock hazard even when unplugged. Instructions for PV inverters typically say to disconnect PV and wait some 5 or 15 minutes before opening.

Some capacitors, if held charged for a long time, will drive charge into the dielectric. You can drain them to zero volts, but after a while voltage reappears as charge leaks back from inside dielectric to plates. Large capacitors can recharge themselves to lethal energy levels. For storage they are discharged and a strap left connected.

So that's why I say to do the math J = 1/2 C V^2; if above 1 joule, take additional precautions.

Some capacitors in research facilities would be a megajoule. I've read that 1 kilojoule can blow body parts off. That would equal the energy from a large handgun bullet. (takes more energy to remove something by vaporization of water than by cutting action.)