rutland 913

[baggypipes]

has anyone a cure for the resonance down the pole of a rutland 913 it is very noisy. NOT the bearings they have just been replaced i have mounted the poles on 1/4" rubber fixings to the main pole fitted with rubber, tried circlips at verious positions along the main pole, now about to try foam pipe insulation down the main pole, at a lost as to what else to try,
i am aware of other makes of wind generators our prob is with this one thanks

 

[SimbaDog]

I will be very interested to see what replies you get
Have not found an answer yet

 

[V1701]

I think the only way to stop it is to have the HRDX controller (might be called something slightly different now) with its switch to power down the generator. Only then will the resonance disappear and you can go to sleep. Been living aboard with one the last year, I think it's the nature of the beast...

 

[VicS]

Two factors to tackle perhaps.
Transmission of noise/vibrations from the pole to the boats structure. Resilient mountings must the the way to tackle that.

Damping any vibration/ resonance in the pole. That might be achieved by clamping a heavy weight around the pole. Thinking about something resembling a shaft anode made of lead . It might need more than one. It might need a bit of experimenting to get the position(s ) correct.

Just an idea.

I don't think the foam insulation will achieve anything

 

[SimbaDog]

I think the only way to stop it is to have the HRDX controller (might be called something slightly different now) with its switch to power down the generator. Only then will the resonance disappear and you can go to sleep. Been living aboard with one the last year, I think it's the nature of the beast...

Yes, have got one & it's great at night

Two factors to tackle perhaps.
Transmission of noise/vibrations from the pole to the boats structure. Resilient mountings must the the way to tackle that.

Damping any vibration/ resonance in the pole. That might be achieved by clamping a heavy weight around the pole. Thinking about something resembling a shaft anode made of lead . It might need more than one. It might need a bit of experimenting to get the position(s ) correct.

Just an idea.

I don't think the foam insulation will achieve anything

That's an interesting idea

 

[macd]

As you're no doubt aware, a solution could be changing the resonant frequency of the pole(s) (since changing the Rutland's frequency is probably not practical). Vic's idea make sense and its use is widespread, for instance to quell high-frequency vibration in motorcycle handlebars. I share his doubt that light insulating foam will help. Heavy rubber sleeving, maybe, but perhaps that's not very aesthetic or practical.

From your description your set-up is one main pole with one or perhaps two bracing poles, yes? Have you tried changing the unsupported length of the main pole? Or perhaps contriving a tensionable stay, which would allow some degree of frequency tuning? This could perhaps be jury-rigged first to see if it has any effect.

 

[ALPHORA]

Spent hours balancing the blades on my 913. I try to convince myself it made things a bit quieter but it still hums when the wind gets up

 

[CAPTAIN FANTASTIC]

Wrap around the pole a strip of roofing lead, say 4 inch, and keep sliding the lead up and down until the resonance stops (or too high picht to be able to hear it).

 

[baggypipes]

913

many thanks for the ideas so far
i have a regulator but use the generator to keep the fridge charged (we live on full time) so reluctant to stop it too often, we do have a 90w solar for when the sun does shine.
will give the weight a try this has been suggested before, not sure a stay would work, we have three fixing positions mounted on rubber,
i'll keep here informed IF i manage to get it sorted
thanks again

 

[ukmctc]

I have 2 rutlands on my Moody but no noise except in very high winds. On the Trapper we solved the noise problem by making the pole one piece rather that the standard 2 piece supplied. The joint needs well greased and made very tight to stop noise on the 2 piece, I also mounted this on the transom on a swing bracket direct to the hull, no noise there.

http://uk.groups.yahoo.com/group/boatingdreams/photos/album/795426066/pic/list

 

[DipperToo]

Been down this route during the past 2 years. New bearings kindly fitted by Marlec and a balance done on the whole system. Experiences/solutions tried are;

1. Main pole and stays mounted on cork/neoprene pads. Also, make SURE that the bolts through the deck are also isolated. I used some builders rubber top hat bolt isolators. Large builders merchants should do these.

2. I tried pipe insulation - no joy.

3. Got a couple of shaft anodes, painted them white and managed to find a couple of spots on the pole where they seemed to damp out SOME of the noise. Dependant on the pole you have will change the best position. Ie, if the pole is open at the lower end, then as a rough guide, divide the length by 5 and the nodes of max vibration should be 1/5 and 3/5 from the top (closed) end. This is to reduce the audible resonsance.

If you proceed to the next step, the pole becomes effectively 'closed' and I then found it was very hit and miss with carefully moving one anode only to see where max effect was gained, then attaching the second anode for a secondary point to dampen.

4. I inserted a small plastic conduit in the main pole and then at 18" intervals injected the main pole with builders foam. This has had the most positive effect so far.

When you also have stays attached, the mechanics can become very complicated in determining the frequency. I did take a short look at recording the sound and analysing the frequency and then seeing if the 'line dampers' (TMD or Tuned Mass Damper) you see onm overhead cables might be effective - those are the ones with a couple of weights on spring arms that can be adjusted a small amount to get to specific frequencies.

I am in no way an expert and last year hoped someone might pop up in this forum to provide an opinion based on science!

The Rutland does generate some vibration when it hits the charge point of rotation as the magnets pass the coils - this is an inescapable fact. I made the decision on the Rutland as it does seem the quietest 'above decks' and I also had a go at Yachting Monthly several times over their tests which totally failed to mount the generators on a 'soundbox' to try and measure transmitted vibration - all to no effect.

FullCircle on these forums also had a similar issue and I believe he had the luxury of possible access to a vibration test rig as used in the motor trade but I am not sure if that ever happened.

Hope the above is of some help!

 

[wizard]

I bought some rubber exhaust supports from Halfords. The rubber is about 10-12mm thick and about 160 mm long. I bought two and cut them to fit under the two main pole supports (4 bolts) and the two support poles (2 bolts each) I made to support the main pole. It was quite easy to drill through the rubber for the bolt holes. They only cost about a £1 each if I remember 3 years ago.

The difference in noise levels where we sleep in the aft cabin was just amazing- even the wife stopped complaining!!

However if the wind force goes above F7/8 then as the others say use your HrDX or HRDi to shut it down.