Put her back up!

[Electron Pump]

  I came up with a few ideas on how to ballance her. I guess I chose a bad one. Really I just delayed the shakey-shakey. Now she is pretty smoothe up to 10amps, but 12.5 ish she shakes enough to make some noise.

  What I did is took her tail and blades off and stuck the body in the vise on the bench. I put the outer ring of blade bolts back in the hub and used a 19.2 volt cordless drill battery to spin up the motor. I took a Sharpie and held it close to the spinning bolts. Two of them was far enough out that they got a little dot of ink on them from the marker. So I marked the hub where these two bolts were located. I then put the blades back on the motor and spun it again, feeling for any vibration. I went threw a trial and error for a long time putting nylon ties on the root of the blades opposite the marks untill I had the least vibration. Or the least vibration I could detect at this RPM.

  I put her back up and she seemed much quieter. But right after cut in she bobbles a little, muck less than before. I wouldnt worry about it except that I can see the problem resurface at a little over 10 amps. And at this RPM it is kinda scarry.

  I spun her as fast in the shop as I could. I dont know how to ballance her any more accurately. Im fairly confident she'll hold together for the short run. But over time its gotta effect things.

  We have a solid week of winds forecast right in her sweet-spot so Im going to leave her up to all the juice I can while I contemplate just how I am going to finish the ballance.

  Oh Yeah, G, you had been talking about a fix with a capacitor. Well I believe my issues are really ballance issues but now that I've quited things down I can hear the hum that I think you was refering to. It sounds kinda like the cogging of the magnets is causing that hum. I think it was Tom said "Thats the sound of making power." I'm plenty comfortable with this little hum.

  Looking back over the weather service 48hour observations history, the big spikes I see in amps seem to match with the reports that the gusts was up around 26 to 28 MPH. So I think I seeing around 10amps at this wind speed. I think thats pretty good for a treadmill. Its just taking so long to see any real voltage gain in the batterys. It will go up to a voltage, the most Ive seen is 13v, and when the mill drops back down below cut in the volts start to tick down. It seems like they dont tick down each time as far but I dont know. Its kinda like its kinda settleing in and slowly dispersing threw the cells. Is that the way its supposed to work. Now the ticking down is without anything using off the batterys so their not being used. I wanted to see the batterys full one time so I could get a ballpark figure of how long it will take to charge my batteries.

[Ungrounded Lightning Rod]

Even a commutated DC motor has ripple from the many coils on the rotor.

When you get to cutin, the current starts going through your rectifiers or anti-motoring diode, but only on the peaks.  So as each peak comes by you get a momentary burst of current.  And each burst of current produces a momentary burst of braking torque as it transfers energy from the rotor to the electrical system.

This series of momentary drags produces a vibration in the mill which is completely unrelated to balance.

As things speed up the portion of the cycle carrying the current becomes wider - though the current is still stronger at the peaks of the ripple than in the valleys.  So the harmonic content goes down but the fundamental frequency is still present to some extent.

Adding a capacitor after the rectifier will tend to increase the burstyness of the current in the genny, not decrease it.  So it will not help eliminate the vibration.  In the DC generator case adding a capacitor before the blocking diode will help reduce the high frequency creation from the diode but will cause the fundamental of the voltage ripple to become a current ripple (and torque ripple) that is present even below cutin.

[Electron Pump]

  Hello UGLR, thank you for commenting. Yeah, it is a noticably different sound. It isnt something I really think I need to fix though. Unless the fix helps me hemm up more of them electrons.

  I really need to get the ballancing issue fixed though. I took an old treadmill motor and beat the magnets outta it. I'm going to try putting my hub and blades over on that motor and see if the bearings will let the heavy blade fall to the bottom. Thats the only coarse of action I have in mind right now.

[Ungrounded Lightning Rod]

You could use the ceiling fan balancing trick, which involves a number of trials:

 - Mount it in a holder that lets it wiggle around a bit.  (Like suspend it from the ceiling.)

 - Motor it up to a low ceiling-fan speed.  (Easy when it's a DC motor design.  B-) )

 - Observe the vibration, then let it stop.

 - Clip a weight onto a blade near the hub, spin it up, and observe it again.  (Try a spring clothespin.)

 - Move the weight from blade to blade at the same radius until you get the least vibration.

 - Move the weight in and out along the blade until you get the least vibration.

 - Put a permanent weight on that blade (with the same product of weight and distance from the hub as the trial weight had, i.e. add heavy bolts and washers to the hub studs to be equivalent to the farther-out lighter clothespin).

 - Then do the whole series a second time to find another location, on another blade, for a second weight.

 - Do a final check to see if you got it dead on with the second weight.

With four blades this converges immediately:  The first weight gets the major imbalance and the second one gets the remaining imbalance at right angles to it.  With three blades the two weights aren't at right angles so they interact a bit and it doesn't always converge completely in two steps.  (And you may find you'll do better by skipping the first permanent weight substitution, continuing with two clothespins until you get it balanced, then doing both weights at once.)

This works amazingly well.

You could probably do the same by skipping the clothespin and using a nut on one stud after another, followed by stacking nuts and washers on the "best" stud (and maybe some smaller ones/stacks on opposing studs if a single nut is too much), rather than moving a clothespin around then in-and-out.

[Electron Pump]

  That makes sence. That is something I will look into.

[tecker]

Deep discharge batts need to be cycled a few times before they start to pick  up the Sg that will remain when they discharge that means the Acid doesn't really drop to a water like solution it just moves out of the spongy lead when discharged So discharge and recharge  a few times . Test the SG with a hydrometer

[Electron Pump]

  O.K. I understand. How far do I need to discharge them. Down to the point where the inverter cuts out? I think mine shuts off at 11.2.

[frackers]

Best is with a known load for a known time.

My bank is 450amp/hrs so if I want to go down by 20% (and I NEVER want to go down by more than 50%) then the closest load I have for C/10 (10 hour rate) is a 1kw load on the inverter so the 40 amps that takes from the batteries (which in my case is 24v) will run for (450/40) * 0.20 = 2.25 hours.

At the end, check the battery after a couple of hours rest and the volts should still be about the nominal value - 12.6v for 12v, 25.2 for 24v. During the discharge expect it to go below that but if the inverter cuts out due to low volts then either the batteries are no good or they don't have as much charge as you think!!