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Old 14-04-2012, 21:14   #76
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Quote:
Originally Posted by hellosailor
engele, when rpm and output are mentioned it is totally pointless to throw about numbers without some context.

In a specific context, a Delco CS130D, which is a most unusually robust alternator, puts out zero amps at 1000 shaft rpm. That's irrespective of engine rpm, that is alternator shaft rpm. By 1500 rpm it is putting out some 40 amps, but it does not supply the rated 100A until 4-6000 rpm (depending on model). On the other hand, that alternator can run all day and all night at 18000 rpm, so it can be belted up to an engine with, say, a 1:5 pulley ratio and put out full power at 800 rpm on the engine--without burning out at 3600 engine rpm.
the vast majority of althernators on the market have a similar need for 1000 shaft rpm in order to wake up and get started, but most of them will crap out at 2/3 of the maximum speed rating (i.e. 2400 engine rpm compared to the 3600 in the cenario above) which many engines could exceed.

So, outputs? rpms? Without knowing the context you're looking at, whether the rpms are engine or shaft, and without knowing the range that the alternator can tolerate?

That another problem with windgens, no matter what dynamo they are turning. Low speed, no power. Higher speed, kaboom.

For high efficiency DC generators, I'm told that modern electric drill motors make good donors. NASA lunar lander technology, premium magnets, mass production, really good conversion of electricity to motion and vice versa. Of course the gearing is all wrong for a windgen, and the max power rating isn't really great, but maybe there's a pony in that pile as well.
Not to make a big deal out of this, especially because I agree it isn't worth the effort, but the OP wanted to know if it was possible. Re-winding the stator of a standard car alternator would yield higher voltage at a lower RPM. High output (100 amp is high) alternators tend to take more RPMs to produce their rated power. In my case a 94 amp alternator would give me more power with my diesel engine because at an idle of 800 RPMs I had a shaft speed on the alternator of 1600 RPMs putting out something like 15 amps. At cruise speed we can get more (but still no where near the 94a rated because our diesel would redline). The 100a that Whatcom Electric talked me out of would barely be producing until around 2500 RPMs.

The way the guy in the shop explained it, a higher output alternator has thicker windings in the stator, and thus less length of wire on the stator windings fits in a standard case. With a smaller gauge wire on the stator windings, more wire can fit on the stator and less RPMs are needed to excite the alternator.

I am not an expert on this, but people have been modding alternators for years to work as primitive wind generators.
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Old 15-04-2012, 10:44   #77
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Re: Car Alternator as Wind Generator?

Why all this talk about alternators? Why not just goto a DC generator like on the pre 1960 cars & VW's up to 1980, I think? It's always a DC output and doesn't need a power source to start up, with no need for diodes.

I'm not sure why they even stopped making them other then they are heavy and require more labor to build. I've had this old one off a fork truck out in the garage for 20 years. All it needs is some clean up, paint and maybe brushes. And have a regulator for it too, that's adjustable with a screw driver.


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Old 15-04-2012, 10:58   #78
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Re: Car Alternator as Wind Generator?

Yeah..... any dc motor is a dc generator right?
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Old 15-04-2012, 12:37   #79
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Re: Car Alternator as Wind Generator?

"Why all this talk about alternators? Why not just go to a DC generator like "
Oh, del. You ask why talk about alternators and then, kinda miss the obvious pont you just made: The industry stopped using generators, there probably was a reason for that.
I think we've mentioned several in this thread.<G>

Even motorcycles have gotten away from generators, my friend's bike is one of the last generator models from that brand, and every year or two, all it takes is one corroded wire contact and the bike eats a regulator. The new models with alternators just don't have that problem, because the regulation is different.

engele, you're right, no big deal here. Windings are a key to alternators, but it sounds like you would benefit from one more like the Delco, which can put out more power at lower rpm ranges. I suppose the drawback to that design is that after you reach 6000 shaft rpm, the next 10000 shaft rpm are "wasted" since there's no additional power really being put out.

But a lot of sailors pretty much have to motor in/out of no-wake or no-wind zones to get off their moorings or berths. Matching the pulleys up so that 20-30 minutes each way provides significant alternator power, can mean that they can stay at 100% charge using just the "have to run the engine" time, as opposed to running it just to charge. Not such a bad way to go, if you're in that situation.

Of course if you are lucky enough to be in "hoist, cast off, hand a right to the Azores"...<G>...different strokes and all that.
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Old 15-04-2012, 17:54   #80
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Re: Car Alternator as Wind Generator?

I thought the 4 Winds was a generator...is it an alternator?
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Old 15-04-2012, 18:39   #81
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Re: Car Alternator as Wind Generator?

Fourwinds calls their 4w-II model a generator. I would suggest that any "permanent magnet alternator" (such as the Blue Winds) is in fact a generator, since it cannot self-regulate the same way that conventional alternators do. The practical breakdwon between alternator and generator is not how they are wired (although some engineers might say it is) but rather the permanent magnets versus the field coil. So an alternator can just cut back the field power to regulate it's output, while a generator entails all sorts of other complications.

Interestingly enough BlueWind suggests a Morningstar MPPT-45 controller, which has sucha high input voltage tolerance that it can be used for solar or wind (windgens easily exceeding 100 volts) and it uses the same dc-to-dc conversion and mppt magic for either one.
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Old 15-04-2012, 21:10   #82
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Re: Car Alternator as Wind Generator?

Quote:
Originally Posted by hellosailor View Post
"Why all this talk about alternators? Why not just go to a DC generator like "
Oh, del. You ask why talk about alternators and then, kinda miss the obvious pont you just made: The industry stopped using generators, there probably was a reason for that.
I think we've mentioned several in this thread.<G>

Even motorcycles have gotten away from generators, my friend's bike is one of the last generator models from that brand, and every year or two, all it takes is one corroded wire contact and the bike eats a regulator. The new models with alternators just don't have that problem, because the regulation is different.
Humm! I still see the things laying around in wrecking yards. I have three in my garage and I'm sure craigs list would turn up a few. And for what reason, that I'd like to know.

But here's a link worth reading....... Alternator and Generator Comparison for Wind Power
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Old 16-04-2012, 10:56   #83
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Re: Car Alternator as Wind Generator?

There's no denying that generators can make better send for wind, ah, generators. And that alternators just aren't built for that purpose. The problem comes back to how do you integrate the power output from a windgen into a recreational boat's power system, which is based on an engine and alternator with an alternator regulator, not a dump regulator?

The oversimplification is that you can't. You can't integrate a totally different system, all you can do is skim off the 12v that it can provide, and throw away the rest in a hot water heater or something. Or use an expensive MPPT controller with a high voltage input to downconvert it. And add a braking system or feather the blades.

As much as bolting up an alternator to a windgen is an inelegant idea...the windgen itself just presents a different set of problems on a boat. Arguably because a generator is too much better than an alternator, i.e. it goes into excessive output too soon.

So on the one hand, alternators are lousy generators. OTOH, generators are lousy alternators. Kinda like this business of life rafts being repacked at incredibly high prices, and then condemned before you've paid them off. There's just GOT to be a better way.

Maybe cheap high-voltage-tolerant MPPT controllers are it.
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Old 16-04-2012, 11:26   #84
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Re: Car Alternator as Wind Generator?

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Twenty years ago I designed and built my own wind generator. In fact I built 11 of them. I used a Ford 100 amp alternator as my starting point. Next I used a mechanical engineer to help me with the mechanical design so the unit was completely enclosed and not subjected to the saltwater environment.

I took my mechanical drawings to Marlboro Foundry in Massachusetts to have a pattern made by a pattern maker so I could have the foundry make aluminum castings. The castings consisted of two identical pieces which I machined in my basement to accommodate the stationary armature along with the rotating field. Other pieces that I fabricated including a base which was sandwiched between the alternator proper and a 2" aluminum pipe that contained half of the slip ring assembly that I designed.

My field used a neodymium iron boron permanent magnet whose flux density was about 12 killogauss, the highest flux available in a permanent magnet at that time. I stumbled with the magnet, could not get it built here in this country without spending big bucks. I found a company in China who made them exactly to my very tight mechanical specification. That magnet looked like a donut. I was mounted between the pole pieces of the old electromagnet field which was scrapped. Note, the pole pieces required machining which I was able to get done on my basement lathe by my Son who is a machinist.

I worried about the armature!!!! The typical auto alternator is designed for high RPMs and slow RPMs I know would cause magnetic saturation in the armature's metal. So I redesigned the armature for a lighter gage wire and had them rewound in a shop somewhere in NY.

Many more details but skipping ahead, I studied propeller design so I could make my own. I had special tooling made for my 5HP wood shaper in my basement. I wanted the cutters to remove most of the unneeded wood stock which it did. Then I build a jig so I could cut the propeller down to where it should be using a router. Afterwards, it still required a lot of sanding using a belt sander.

The propeller ended up being 4 blades, 5' in design. The reason for a large blade is captured wind energy is equal to 1/2( d*A*S^3) where d is air density, A is the blade swing area and S is the wind speed.

My machine developed about 12 amperes with winds just over 15 knots. Even with the redesigned armature, I could see core saturation occurring at low RPMs when I rotated the shaft on my lathe while looking at the armature waveforms with a scope.

I planned to market this thing!!!! FEAR OF LIABILITY stopped me from manufacturing them.

So you want to build your own windgenerator!!! GUYS, think what is involved to do right before you do anything.

Foggy
That is a lot of money, and engineering to realise at the last minute, OOOPS I need liability insurance to run a business.
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Old 16-04-2012, 13:00   #85
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Re: Car Alternator as Wind Generator?

I was an engineering manager responsible for several large design projects with a staff of 25 engineers working for me. Money at that time was no object.

I have a business today with a business partner. We own and manage 19 rental apartments and built houses back around 2000. AND WE HAD LIABILITY PROBLEMS.

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Old 16-04-2012, 18:04   #86
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Re: Car Alternator as Wind Generator?

The oversimplification is that you can't. You can't integrate a totally different system, all you can do is skim off the 12v that it can provide, and throw away the rest in a hot water heater or something. Or use an expensive MPPT controller with a high voltage input to downconvert it. And add a braking system or feather the blades..

I guess I just dont get this..... something I dont understand I guess. Why do the batteries care if it comes from a gen, alt, taffrail charger or solarpanel? Are you saying people cant monitor their battery charge level?
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Old 16-04-2012, 20:23   #87
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Re: Car Alternator as Wind Generator?

The batteries don't care. But do you really one one regulator for the engine alternator, plus a second MPPT controller for a solar array, plus a third dump regulator for the windgen? As opposed to some way to integrate all the power, and especially not to just DUMP power as the windgens do?

Although if you have a nice fifty gallon hot water tank and want to preheat that every day, the dump regulator on a windgen certainly is a nice way to do it.<G>
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Old 17-04-2012, 08:07   #88
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Re: Car Alternator as Wind Generator?

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Originally Posted by Cheechako View Post
The oversimplification is that you can't. You can't integrate a totally different system, all you can do is skim off the 12v that it can provide, and throw away the rest in a hot water heater or something. Or use an expensive MPPT controller with a high voltage input to downconvert it. And add a braking system or feather the blades..

I guess I just dont get this..... something I dont understand I guess. Why do the batteries care if it comes from a gen, alt, taffrail charger or solarpanel? Are you saying people cant monitor their battery charge level?
All the batteries care about is getting the correct current for the correct time, and to stop charging when they reach the correct voltage.

The problem is each of those sources other than a shore power charger, have different voltage, and current ratios,and....the ratio changes suddenly when you get a shadow, or the wind shifts.

This the battery doesn't like. Charge controllers try to even this out and give the correct voltage current ratio the batteries like, and stop when battery is full.

But the same controller, (unless built for it), can't change a source that changes voltage, but keeps current the same, AND a source that changes current, but keeps voltage the same, at the same time.

The problem with wind generators is when the wind picks up they generate TOO much power, (and about the same time the battery is full), the power HAS to go somewhere to load the generator to keep it from flying apart, so you essentially short the output to a shunt.

Solar panels are the opposite to control output power you just open the circuit, they don't like being shorted.

Worse to charge a battery a charging system has to put out more than the voltage of the battery, (but not too much), The other charging system uses the voltage to tell if battery is full, so the charging voltage from the other system will fool it into thinking the battery if full, and it will stop charging, if you have too much of a mismatch one charging system will backfeed into the other instead of the battery, and neither will work.

I'm sure there are people out there that have cobbled together systems and had them work, or have a switch to pick whichever one is producing the most power.

But you just can't hook the wires from the windgen to the solar panels without some smoke.
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Old 17-04-2012, 08:41   #89
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Re: Car Alternator as Wind Generator?

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I agree, if for no other reason than that there won't ultimately be any cost savings. Not accounting for the labor, by the time all the necessary materials are purchased or fabricated, you will have already been able to purchase a comparable wind generator ready to go in the box.
I Disagree,
Lets take the given on most boats.
A 10ft pole and braces...cut that cost out.
If i put a 90amp AC Delco at the top and have the basic welding skills and a good let me go look junk yard close by i think it is entirely feasable to do.As far as gearing goes......
As for the blades i had a empty 55 gallon drum escape my boat south of kenora,canada.[air boat] Actually a 20ft plywood hull with a 6cy ford and a prop on the drive shaft.
Said drum shatered the blade.Spent 3 days with a chainsaw and a piece of rebar to make holes fabricating a new blade....and it is still running on a boat up there.that was 20 years ago......
So i think the wanting/needing to do it guy can make his own blades.
So now we are down to COST........
Yup,I just bought a new air-breeze......cause the cost was cheaper than my time to make my own.....
Your millage may vary
Mark
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Old 17-04-2012, 09:13   #90
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Re: Car Alternator as Wind Generator?

Have you buit your windgen yet?
Are you any the wiser as to why people just find the money to buy one ready deisgned, tested and certified, and which WORKS ?

If it was that easy, everyone would be making their own. Look closely and you see that all which glitters isnt gold.
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