Wind generator wierdness

[GILow]

Hello Cruisers,

We have an old Aerogen 6 wind generator on our boat. It has been working ok, though I have never used it in strong winds till now, as it had rumbling bearings with a flat spot from being parked in the tied off position for the better part of ten years, was quite badly out of balance and I felt the strain from over 15 or so knots apparent wind would not be a good for it.

So, I got all enthused, hauled it down, stripped it, fitted new bearings (only $18 each ), sanded, painted and balanced the blades, repainted the chassis, and even, in a fit of silly enthusiasm, put neat little black speed stripes on the blades. (They look really good when the blades are moving fast!)

Then, as good luck would have it, there was a forecast for some seriously strong winds last night and I knew the house bank was down to about 12.6 volts, what a great time to test things.

So I belted down to the boat, untethered the blades (the Aerogen 6 is supposed to be left tied off when not in use, as against the 4 and 2 which can look after themselves.) and waited for the wind to come.

Well it did come, no idea what it was blowing, as I didn't think to turn the instruments on, but it was enough to shake us around in the pen.

Alas, things did not work as I expected. The amps started to climb up to 3, 4, 5, then phhtt... back down to NEGATIVE amps, around -1 or maybe more. It would do this for a few seconds, and you could see the blades slow right down, then suddenly it would go postive half an amp on the ammeter, the blades started spinning up again, 3, 4 amps... then phhtt! Back down to negative amps again.

Now these current readings were from a new analouge ammeter fitted on a dedicated link to the windgen's regulator, so they are not influenced by anything else in the boat, which was shut down anyway, except for a few cabin lights.

I also confirmed the current readings from the house battery monitor system and it was telling me just about the same thing (minus a bit for the lights that were on) albeit much slower because of the digital readout.

House bank voltage would climb to 12.8, sometimes 12.9 when the 3 or more amps were coming in, but then slowly drop again when the ammeter went negative. Unfortunately, the only volmeters I have on the house bank at the moment are digital, so there is a bit of a delay in the readings.

ANYWAY, I went aft to the regulator, which is in a compartment behind the engine with a great big heat sink for the dump resistors, and found that it was buzzing away, apparently alternatly dumping power into the resistors. I tapped in my multimeter at various points to check that it was not seeing incorrect voltages due to cabling problems, but nope, it was seeing excatly the same battery voltages the rest of the system was seeing, which it should as the cables are all new and specced for 50 amp loads, not 3 or 4.

So, this FEELS like a regulator problem, but for one thing.

I am bother by the reverse current I observed. I certainly saw negative current flowing back out of the battery bank into the regulator when it was shunting power to the dump resistors. Maybe, just maybe, that is just a relay load to perform the shunt, but I am wondering if it is something more ominous.

If it is normal, then I suppose the reg is out of calibration and simply thinks 12.8volts or so is fully charged, it is supposed to cut over to the dump regulator at 14.2 volts.

But maybe it is something else, something I have missed. Any ideas?

And if the reg is kaput, then what better time to retrofit with a regulator that is better suited to alternative battery chemistries. As it is, 14.2 volts is perilously close to the Lithium maximum, and I would rather there was room for error in the system if I ever fit lithium batteries. If I pursue this path, does anyone have a recommendation of a good windgen regulator that can handle 30 amps and shunt to a dump load resitor, while allowing user calibration of the cutout voltage?

P.S. Forgot to mention... before the rebuild I had seen it putting out a good 15 amps or more, but that was a year or so ago now.

Matt

[nigel1]

Sort of sounds like there is a short in the wirers between the wind gen and the regulator. You mentioned that as the amps dropped, the blades slowed down.
I dont know a great deal about the Aerogen unit, I have a D400.
That has a switch in the cables between the wind gen and the regulator, and is used to short the wires which slows down the wind gen. The maker calls this a Brake Switch.

As regards a replacement regulator, I think the 6TB is recommended. Voltage can be adjusted between 11.5 and 17V.

See this page for more details.
http://www.shop.solar-wind.co.uk/aca...structions.pdf

[GILow]

Nigel,

Thank you for that link, you have actually given me hope that my current regulator is adjustable, since I think it is that very model. Certainly looks the same.

Maybe, just maybe, the pot is getting tired and has pushed the cutover voltage right down. If so it will be a simple soldering job. I will check at the first opportunity, I have to get down to my local electronics store on Friday for some other bits and pieces anyway.

Matt

[Randyonr3]

went throu my 4-winds awhile back and decided to get rid of the old-age regulator it was designed to run with.. Found the morning star TS/45 to meet the needs I was looking for..

[GILow]

Thank you. I will check that model and see if it is compatible.


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[MBWhite]

These issues are always hard to diagnose without actually looking at them, but since you just changed the bearings it could be a mechanical issue instead of an electrical one of a bearing is binding up and slowing the blades down that way. Be aware that it may only do it under a load, which can make it doubly hard to isolate but you could start by checking bearing temps in the middle of a brisk wind, just figure out how you are going to do it first.

[sy_gilana]

The standard reg has a pot hidden on the back of the unit.
The Standard reg is not the best but with LiFePo batteries you must be careful.
Some MPPT controllers have a wind gen input.

I have rebuilt a LOT if Aerogens. You must, and probably have done this but here is how I balanced them.

Weigh the blades, several times, average the weights.
Place the two heaviest opposite each other, and then the next two and the last two.
Find a flat surface, I love a glass table with an umbrella hole in the middle.
Place the hub in the hole, and lay out the blades face down. Get six identical matchboxes, and place them under the tips of the blades, so that the tips are horizontal, parallel with the table. (ignore the alignment marks) This is the best pitch setting. Slowly tighten in a pattern observing that the tips still are flat.
When done, and its up and running, look from the edge and you should see a flat unwavering disk with all tips in the same line.

Its too late for this but, I used the 2RS bearings, ie 2 rubber seals, but removed 3 of the seals that are inside the hub. This allows the unit to start at 4-5 knots.

A brake switch is a good idea.

If your tail boom is a hollow aluminum pole with a black plastic plug, remove the plug, and you can put a 1/2" aluminum bar in there, then to stop the gen you slide the bar out to fit between two blades.

I used a plastic cap from a bug spray can, made a hole in the end, and fitted it over the end of the nose of the hub mounting on the shaft so it spins and slings water from even reaching the bearing, and smeared grease over that front bearing edge.

good luck!

[GILow]

Sy_gilana,

Thank you for that terrific info. I really appreciate the tips on blade alignment and I will remove the blade assembly and follow your steps. I was happy with the balance but not the alignment. There is a visible "shimmy" albeit small but very frustrating.

Your bearing modifications are also very interesting. I will see if I can apply them to my new bearings which were some kind of " extra sealed" things. Not sure what was special about them but they were the only bearings the guy had in stock so I was not too fussed if they were special or not

Thanks again

Matt


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[GILow]

Originally Posted by MBWhite

These issues are always hard to diagnose without actually looking at them, but since you just changed the bearings it could be a mechanical issue instead of an electrical one of a bearing is binding up and slowing the blades down that way. Be aware that it may only do it under a load, which can make it doubly hard to isolate but you could start by checking bearing temps in the middle of a brisk wind, just figure out how you are going to do it first.

Yes a good point and I feared I had buggered the bearing installation somehow. But the blade speed variation was right in synch with dump resistors switching on ( they make a noticeable buzzing sound when active) so I am suspecting the reg at this point. Still I will double check when I pull the blade to improve the alignment as per the instructions provided.

Matt



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