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Harris turbine bearing replacement

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Buzzsaw:
Greetings, all. I have a 48V Harris pelton PM turbine that's been running pretty much non-stop for about ten years. A couple of weeks ago, it suddenly started to make a low frequency, grinding sound. It still is generating power, maybe at about 90%. Hard to tell because I'm starting to move towards a low water time of year.

I suspect that a bearing or bearings are going, but there's precious little information on what replacement bearings are used and what the preventative maintenance cycle is.

Any information on the specific bearings needed or any other thoughts on the symptoms would be greatly appreciated. I see mention of a 6203 bearing from a post in 2010, but there are so many sub-space to the 6203, I'd just be guessing without taking the turbine offline and disassembling (it's up in the Cascade Mountain Range). Thanks!

 - Marc

thirteen:
Possible calling the manufacture and ask. Being 10 years old things have probably changed. Unless you have an old book on them, tearing it down would be the last resort to get the numbers. Because it would shut you down  for at least 2 days, unless you have a backup you could use for a couple of days. I don't know the distance for parts. Me I'm 45 miles from the nearest parts place so a 90 miles round trip. If they would have them.
To maybe get you by as an idea if you can see the seals on the bearings use a small syringe with a small needle and inject into the bearings some grease. I assume these are greaseless bearings. This works but it will not be good for long duration. It will get you through. Bad bearings going out will as you know cause windings to get trashed.
I think stream engine turbines say to replace the bearings every 2 years. Two of my neighbors have that style of turbine. 13   

SparWeb:
The 6203 is a very common ball-bearing design making it easy to find in a wide variety.  It's likely that ANY 6203 will fit and run - but will it last as long?  I bet this bearing isn't working too hard if it has lasted so long.  Sometimes you can figure out in advance if the bearing is heavily loaded or not, to determine what quality you require.  If you got 10 years out of these bearings under the combination of speed, load, and torque between your Pelton and the genny, then it's a safe bet that an equivalent bearing will last as long.    Can you stop the turbine temporarily and read the part numbers on the side?  Bearings are often hard to access so there's only a small chance you can do this.  Getting a look at the kind of grease shields in it would also help.  I would be surprised if it wasn't sealed.

Given the life you expect, and spreading the cost of a high-quality bearing over 10 years...  just pay for a SKF or a FAG bearing and don't worry!

thirteen:
Side note. If by chance you find out that you have an odd set of bearings and seals and they are hard to get. You might want to get spares and put them on the shelf. 10 years from now they maybe harder to acquire. Be sure and date the spares if you decide to get them. Plus any problems you had replacing them. 13

skid:
Take it apart before it self destructs. There should be one bearing on either side of the pelton wheel on the shaft. The bearings will have a number stamped on them. One bearing is likely a deep groove ball bearing designed for both axial and radial loads, the other end is probably a standard groove ball bearing designed for radial loads only.

Buy new bearings and re-install them. Should only cost you $50 or so. You'll likely need a bearing puller to get them off the shaft. To get them back on the shaft easily, put your oven on approx. 150F and heat the bearings a little so they grow a few thousands of an inch. They will slide easily onto the shaft.

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