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Old 09-12-2014, 03:37   #1
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Electrical braking on an Aerogen 6

Hello Cruisers,

We have an Aerogen 6 wind generator on our boat, fitted some time in the late 80s. I recently replaced the bearings, repainted and rebalanced the blades and now it is like new again.

Now the manual for the Aerogen 6 states that it is not suited to unattended operation in winds over 45 knots, presumably because it would be damaged by over revving. As a result I have always left it tied off when we are not using the boat. ( I should mention that the batteries are managed by a reasonably smart solar regulator so I don't leave the wind generator connected to the battery when we are not using the boat. The regulator gets confused by the solar regulator and ends up switching the dump load on and off constantly.)

But last week it suddenly struck me that the chance of winds of 45 knots hitting our boat in the pen are practically zero, and if strong winds are forecast I tend to go down and check the lines etc anyway. Tying the Aerogen off is fiddle and a bit risky as it is up very high and you are technically outside the line of the boat when you carry out the procedure. Also, leaving it tied off for long periods apparently causes the bearings to get flat spots and develop a knock, which we were experiencing before I replaced the bearings.

So I tried electrical braking by shorting the outputs and the effect was startling. In 25 knots apparent wind speed it reduced to something under 70 rpm. We rarely see more than 10 knots when in the pen. Current being induced in the circuit was about 8 amps at that 25 knot wind speed. Voltage was, of course, too low to measure with a total short and Awg 8 cables.

So, all this leads to the following question: as far as anyone knows is there any downside to this arrangement in terms of potential damage to the Aerogen? I mean at an electrical level does this sort of thing significantly reduce the life of the magnets in the rotor?

(I just edited this post as I remembered there are no brushes in the generator housing so I don't need to worry about increased brush wear)

Any gotchas I should consider?

Matt


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Old 09-12-2014, 14:01   #2
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Re: Electrical braking on an Aerogen 6

While I have no particular experience with wind generators, in general shorting it will mean the power is being turned into heat in the wiring.
Not good for the wind generator. However being out in the wind, they might be quite capable of removing the heat from itself without any damage.
Unless it is real hot outside, or the windgen is insulated, or has thin wires..
so the usual.. it depends. In a previous thread on the topic here, some have said it was no problem with theirs, at least no immediate problem.
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Old 09-12-2014, 15:01   #3
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Re: Electrical braking on an Aerogen 6

Hi Nimblemotors,

Any idea on the location of that thread? I have searched without success and I was hoping the issue had been discussed already.

Matt
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