bearings: different grades & qualities

Give Mercury Bearings a ring

Small business who know where they're at

the generator is a wind turbine. The bearings are to a small degree exposed to the elements, or at least the moisture and constantly varying temperatures of the outdoors. The turbine is high up and getting access to it means erecting a scaffold tower. All of this is a lot of work simply to replace bearings, thus I want a grade that is going to last. I expect that 'any brand name' might not serve the purpose, the cheap type might start rumbling or squealing after a couple a months, thus I want to get it right when I have to re-install the turbine high in the sky. It's no joke assembling a scaffolding tower and then building up the turbine at the top of it. Ideally I'd like to service the turbine only once a year, or maybe even once every 18 months if possible, and fitting top knotch bearings might get me that.

In message , Clive George writes

This is where you need the experience of a good distributor who knows their stuff

Manufacturers are not the best people to ask as they will always promote their product.

I think 6203-2RSH bearings are sealed on both sides

you could get 6203 Z or ZZ for (single or double) shielded ones

Yes most bearings come in shielded or sealed versions

In message , Tim Lamb writes

... ...

I think you must be a bit rusty

most mid range bearings are Japanese nowadays (but made in Malaysia, Indonesia, Korea etc)

In message , Sylvain VAN DER WALDE writes

Use the old bearing ...

the elements, or at least the moisture and

getting access to it means erecting a scaffold tower.

that is going to last. I expect that 'any brand name'

after a couple a months, thus I want to get it right

a scaffolding tower and then building up the turbine

maybe even once every 18 months if possible, and

Rather than worry about "top knotch" bearings, (any good brand will do) I suggest you concentrate on improving the environment in which the generator will exist. Namely full enclosure. Presumably this an automotive based generator, consider the underhood environment of a car in the Midwest, hot, cold, freezing, dry and wet. Yet the generator bearings survive... From a maintenance point of view, you could look outside the square and design your tower so that the generator assembly could be lowered to the ground for servicing without actually have to erect scaffolding. Such designs are commonplace down here. Simple cable operated latches lock the generators in place atop the tower.

Tom

Tom

I've never tried that, so can't comment.

Sylvain.

Very interesting and useful.

Sylvain.

As stated above "at short notice". It's definitely not an "Urban Myth". It's true, and I'd wager on it.

I don't think that regulations that are mandatory to civilians apply to the Armed Services.

Sylvain.

In message , raden writes

Yes. I was actually on the electrical side so I refuse to be embarrassed:-)

SKF took a big hit from the Japanese in the late 70's. My *hearsay* understanding was that by relaxing the groove tolerances much quieter bearings could be marketed for use in *quiet environment* electric motors. In factory scuttlebutt at the time was that this would lead to shorter life and reduced functional performance.

I have direct personal experience of a particular range from Asahi (deep groove, self aligning) and believe they are not as good as other manufacturers equivalents.

regards

You should. You'ld be amazed at what a bright girl can pick up at an engineering company..apart from a 'dose' of course..

the elements, or at least the moisture and

getting access to it means erecting a scaffold tower.

that is going to last. I expect that 'any brand name'

after a couple a months, thus I want to get it right

a scaffolding tower and then building up the turbine

maybe even once every 18 months if possible, and

Go for stainless steel, oil lubed and fully shielded.

If corrosion/dirt rather than actual wear is the problem.

There are various grades of steel used as well.

Not sure where you got that info. DuPont did a study on bearing quality and Toyo (Koyo?)) wasn't even considered. NTN had the highest quality rating and as a result, DuPont corporate policy is to use NTN only.

common size - 6302-2RSH. What I want to know is, do

want to replace these bearings with the best I can get.

Bearings do come in different grades and qualities but most generators use bearings made to ABEC-1 standards as high precision is not needed. All that means is that the ID, OD and width fall within certain tolerances but has nothing to do with surface finish, concentricity etc. I would definitely stay away from Chinese - some are reasonably good, some are real trash and you don't know which you may be getting and the same holds true for India. Any bearing from a major manufacturer (NTN, NSK, SKF, FAG, Fafnir etc) will suffice however, NTN has been considered to be a top brand for electric motors for years. In a DuPont comparison, NTN ranked highest in the world in quality and adherence to tolerance but the differences are negligible for all practical purposes. Sealing is another issue - most electric motor (and generator) bearings are shielded. Cheapest and fairly good at blocking dirt but doesn't do anything for water. Sealed is best but a full contact seal creates friction and increases start up torque. Your best bet for this application would be a non-contact seal such as the LLB suffix on NTN. A sealed or shielded bearing is also "lubed for life" so you really don't need to grease it - just run it until it begins to fail. Most bearing failures are caused by over lubrication. Also, most manufactures have gone to an "EM" designation for electric motor bearings which means they have certain qualities preferred for electric motor applications. This automatically includes C3 internal clearance for a press fit on the shaft. If the bearing doesn't say EM then you need to make sure it does say C3. Good luck with your selection.

the elements, or at least the moisture and

getting access to it means erecting a scaffold tower.

that is going to last. I expect that 'any brand name'

after a couple a months, thus I want to get it right

a scaffolding tower and then building up the turbine

maybe even once every 18 months if possible, and

Hi,

Try alt.energy.homepower and maybe alt.energy.renewable, and trawl the archives of them. There's likely to be good info on maintaining wind gens at least, and maybe something on the best bearings for them too.

cheers, Pete.

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember tomcarlson(REMOVE)@sbcglobal.net (Tom) saying something like:

If that works for them, fine. Toyo are outstanding, imo and experience.

Looking NTN up, as I hadn't come across them, it seems that Toyo and NTN are very closely tied up anyway.

With the exception of stainless, ceramic, or even Delrin.

How about "Most ball bearings...."?

Kevin Gallimore

If your bearings are starting to go out after only 2 months, that is only 1500 hours. And if I assume that many of those hours are not high load (or no load), I'd say you have a design problem that won't be solved with a better bearing. Moisture, dirt, axial loads, overloads, bad mounting surface all come to mind.

I'd certa>

the elements, or at least the moisture and

getting access to it means erecting a scaffold tower.

that is going to last. I expect that 'any brand name'

after a couple a months, thus I want to get it right

a scaffolding tower and then building up the turbine

maybe even once every 18 months if possible, and