Cheap chinese horizontal wind turbine, an in depth exploration.

[brandnewb]

For that shorted wire case, would be interesting to measure current, also temperature rise of the windings. It is a common "brake" technique, would be good if it works well enough without damage.

Do you have a clamp DC ammeter (I bought one from Harbor Freight). Do you have a thermocouple or IR thermometer?

would running this test at 320 rpm be of use?

 

[Porch]

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

Don't be sad until you
A) Use the cap in this circuit
B) Put 4 of the 12v lights in series to make a 48v light.

 

[brandnewb]

A) Use the cap in this circuit

what is a cap and how do I apply it? I am ready to rock even though I should be sleeping now

 

[Porch]

what is a cap and how do I apply it? I am ready to rock even though I should be sleeping now

The capacitors you ordered. Or "caps". See my wiring info above on how to wire it.

 

[brandnewb]

Or you can connect it to a variable 3 phase load

Would there be some examples of those? btw, I am no longer in my garage can you please give me a link to your cap wiring. I somehow fail to notice it while backtracking this thread. Once I am up again tomorrow I'll get this show on the road

 

[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.