Replacing bearings on Rutland 913

[phantomlady]

Hi, has anyone any experience of replacing the bearings on a Rutland 913 wind generator??
It says they are 'sealed for life' but ours are making horrible knocking sounds in light winds.
Do they need replacing? How difficult/easy a job is this?
Any advice would be appreciated......
Thanks

 

[Rivers & creeks]

Yes I have experience - and after those 3 hours I packed the Rutland up and sent it to Marlec who did it for me! Soon people will come along and explain how easy it was to do, I found it a nightmare and the exceedingly helpful chaps at Marlec said that they didn't regard it as a DIY job even though they wil sell you new bearings and instructions. They put new ones in, completely rebuilt and refurbished the machine and charged me £70.

 

[ksutton]

Its not a simple job, there is some degree of difficulty and would say you do need "hands on" mechanical experience, even then the bearings are not very easy to get off the rotor shaft, ideally needing a workshop press.

 

[rhills]

Yes, I've had my Rutland apart several times, the first time to replace the bearings, though it turned out they didn't need it. BTW, you can easily buy the bearings in any bearing shop. I have a PDF from Marlec entitled "Hub Bearing Replacement" that details the process and even spells out the specs of the bearings which makes it easy. IIRC, I paid about AU$ 3 or 4 each (about 2 GBP) for mine.

However, as I mentioned, it wasn't the bearings that were the problem. Wind Generators generate electricity by having a large magnet spin around lots of wiring (called a "winding" or "coil"). In the Rutland, the winding is pressed into a large disc (? ceramic) that the magnets then clamp around (the big disc the blades are attached to is all magnet). When I pulled mine apart, I found melted plastic smeared all over the surfaces of the magnet, causing friction and noise when you turned the blades. I cleaned off the melted plastic and put it back together and it all worked fine.

Where did the melted plastic come from? Cable ties that held the wire windings together - in some spots on the disc, they were sticking out a little proud from the ceramic (or whatever material the disc is made of) and in one of our winter storms (50-60 knots) vibration presumably caused the magnet surface to contact with these at high speed causing them to melt.

I should point out that I was never completely happy with my cleanup job and about a year or so later, the wind generator stopped generating. In response to an email query, Marlec kindly provided me with some simple diagnostic measurements to make (using a multimeter) that confirmed my suspicion that the windings had failed. I bought a replacement winding and installed it quite easily and the unit has worked well ever since.

Now, I always tie it up when I'm not on the boat or if the wind gets over 30Kts.

Cheers,

Rob Hills
Waikiki, Western Australia

 

[phantomlady]

wow! always so impressed by the range of knowledge on these forums and peoples willingness to take time to explain and help.
Thanks guys - we will take it apart and have a look before buying any spares.........

 

[rhills]

If you've ever worked on a car, or changed your diesel fuel pump, you should be quite able to do the bearings on your Rutland. I believe that if you're likely to travel any distance in your boat, it's useful to know how these things work and how to do basic maintenance yourself. The Marlec workshop may not always be nearby. So if you're not pressed for time and are interested to learn, have a go.

BTW, I forgot to mention that you will probably need to buy, beg, borrow or steal a suitably sized bearing puller as the old bearings don't come off easily.

That is of course assuming that it is the bearings that are the problem.

HTH

 

[rhills]

Marlec publish some quite good electronic documents for the Rutland, including a Troubleshooting guide and Instructions for replacing the bearings.

You can either download them from the Marlec website Support page after registering with them, or you can find them elsewhere by doing a Google Search like this one .

 

[rob2]

Just a word of warning. If you tie up the blades, the bearings will wear faster as they vibrate on a single spot. It is better to leave the generator spinning. But if you want to stop it, tie it up and place a bag over the generator so as to stop the blades from trying to rotate.

Rob.

 

[elton]

I cut the old brearings off my 503 with a Dremmel. Replacement bearings were about £5 at a local engineerimg supplier.

 

[Ardenfour]

I replaced mine around 6 months ago and noticed last week it was knocking again. I don't think it's the beartings this time though. There's play in the shaft but it spins smoothly. The bearings' inner race is glued to the shaft and outer glued into a recess in the plastic hub moulding. The adhesive is a Loctite product, Marlec quote a number. It cost a ridiculous £26 for a 5ml tube, ( I paid £3 per bearing) I used a similar adhesive from RS Components for a fiver. I think on mine the bearing/plastic joint has come adrift (false economy on adhesive?) I've not taken mine apart yet to check.
I got the bearings off using a small 3-clawed puller but I had to grind the claw ends thinner as space between bearing and hub is very linited.
You will need an adhesive on reassembly, apart from this it's all pretty straightforward once you start (watch your fingers when the two hub halves come together!)

 

[elton]

I got the bearings off using a small 3-clawed puller but I had to grind the claw ends thinner as space between bearing and hub is very linited.

Yes, you remind me why I ended up cutting the bearings off with a Dremmel - none of my 3-legged pullers would fit, and I couldn't buy one that would.

 

[SimonJ]

Tieing up a Rutland

Just a word of warning. If you tie up the blades, the bearings will wear faster as they vibrate on a single spot. It is better to leave the generator spinning. But if you want to stop it, tie it up and place a bag over the generator so as to stop the blades from trying to rotate.

Rob.

Maybe it is dry in Oz but in the rest of the world you need to let the Rutland spin to expel moisture from the bearings - otherwise you WILL need to replace them ......Brinelling while staionary not a good result either!

 

[rhills]

It's normally very dry here in Perth, relative humidity is usually in the 50s or lower on the coast. I've never had a problem with my bearings despite my Rutland having probably spent 95% of its life (since the rebuild) tied up.

I replaced them the first time I opened it up because I'd foolishly gone out and bought the bearings before checking what the actual problem was.

WRT removing the bearings, I was able to buy a suitable puller from the place I bought the bearings from. It had 3 long, narrow legs with quite short claws on the end. From memory, I had to put something in the middle of the 3 legs once they were in place to stop them falling inwards and slipping off the bearing.

 

[DogWatch]

Maybe it is dry in Oz but in the rest of the world you need to let the Rutland spin to expel moisture from the bearings - otherwise you WILL need to replace them ......Brinelling while staionary not a good result either!

NO!

please for the sake of mutual sanity, please don't start this one off again!

 

[rhills]

Uh, Que??

You may have to provide a little more detail to let whomever has sinned know what they've done wrong... Maybe a link to another thread???

 

[davey]

Rutland 913 Bearing Swap

Been there done that on a machine that looked as if it has been used as an anchor. The problem was that it is an old one that must have had the biodegradeable plastic nacelle. Now I would bet a pound against a Zim dollar that it was left out in the weather without any protection at all and left there even after it seized. It was seized solid, even the azimuth pivot! Inside the bearings were red rusty and totally knackered. To get to the bearings the six screws on the two plastic hubs need to be unscrewed but before you do this remove the fan blades, the rear nacelle and the front trim piece (underneath the trim piece the hub will say "Rutland 910" but this seems to be a hangover from the Rutland 910-3 which is probably electrically the same so don't worry!) You will need to unplug the wires inside the nacelle and loosen the clamp bolt that holds the spindle in the aluminium block. Plus-Gas or WD40 may be needed to ease the spindle out of the block. You now should have a hub with a hollow spindle and wires. Remove the six screws and begin to pry apart the two halves of the hub. This needs levers and wedges if you have any as the magnetic attraction between the two halves is several kilos. Once you have got the stator out (the stator is the central disc) the bearings can be removed. As they are not being used again it does not matter if they are destroyed. A puller can be used on the front bearing if you have one with thin claws but on the rear bearing the spindle and wires rule this out. If you have a good strong engineers vice (not a mini vice) the ball races can be squeezed until the outer races shatter WEAR GOGGLES and cover the race with rags in case of flying pieces. Next the balls and cages can easily be got rid of which just leaves the inner races. If one has an a small angle grinder (a bench grinder or Dremel would also do) grind two flats on the inner race. With any luck it may split of its own accord, (try to avoid grinding the spindle) The inner race can now be turned with Mole Grips or an adjustable spanner. I was lucky enough to have a lathe available so whilst I was at it I drilled and tapped the nose of the spindle 6mm so that next time it can be pulled out of the alloy block with a slide hammer. Stainless steel bearings were fitted this time and they were bought from GAP bearings on eBay. The lathe made pressing them on a doddle although one didn't need any pressing at all! Loctite to the rescue. I also used Loctite on the outers of the races as the more suitable special low strength product couldn't be obtained. Ensure that the new races go right up tight to the shoulders on the spindle as otherwise the hub halves won't go together properly, even with bearings up tight you may need a G clamp on the hub halves - do this before the Loctite sets! (watch out for the hub halves grabbing one another by having spacer wedges that can be eased out gradually) IMHO the reason why these machines must never be tied-off isn't Brinnelling at all. It is because the machine is not hermetically sealed and water (even seawater) can get in when it is stationary (wet can also get in when it "breathes" owing to temperature changes). When it is spinning any dampness is centrifuged out, Voila! Next job is making a new azimuth spindle as the old rusted one is riddled with drill holes from trying to split away the corroded-on adapter boss. Weather had got inside the alloy block and had destroyed the brush gear and the lower bearing. It may be advisable to remake the nacelle from GRP as the OEM version was a failure. Hours of amusement and personally I'd recommend other makes. If the housing nacelle is good and the inside of the machine lanolined-up one should be in business and with the cost of new machines being so high one does need to maintain them properly. Good luck and take it steady as its not a 5 minute job when they get as bad as this.

PS If the machine is in a bad way please check the continuity of the windings before doing all this work as quite often worn bearings can cause an open circuit stator. New stators are no longer available for the Rutland 910 single phase machine.

 

[Mistroma]

Very useful information.

I'd always assumed that the main reason for not tying the generator up for long periods was to prevent water running inside along the shaft. That's probably because I'm based in Scotland and rain is not exactly a rare phenomenon here.

Last winter I decided to fold my 913 pole down across the stern and put a plastic bag over the unit followed by a woven plastic sack. The covers were open at the bottom and the tail was held facing upwards by a line leading to the cockpit cover support.

I figured that a combination of cover, ventilation and downward facing rotor shaft would protect the unit. However, I've just put it back up and when I was leaving the wind piped up. It's making a deep whirring sound audible from at least 40-50 feet.

It was new at start of 2010 so doubt bearing are worn. I'm going to dismantle it next time I'm at the boat. So information here is very useful. Earlier in the thread someone mentioned that he had something inside fouling the rotor. That sounds like a possibility. I can live in hope as it sounds like a much simpler fix than bearing replacement.

Good to know that bearings are readily available and cheap. I suspected as much as I used to buy various bearings from Bearing Services Ltd many years ago and mark up in auto trade was massive for some types.

I also used to get replacement shaft seals from them for my sea loo. Prior to looking up the part no. I had to buy a complete set of bits I didn't want (for £30) to get the seal I needed. Once I had the part number I could but 4-5 seals for around £5-£6.