LOOKING FOR CERAMIC BEARINGS OR A 16MM SHAFT

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STEVE K
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LOOKING FOR CERAMIC BEARINGS OR A 16MM SHAFT

Post by STEVE K » Sat Nov 07, 2009 9:32 pm

I WAS LOOKING FOR INFORMATION ON FINDING A CERAMIC BEARING FOR A 14 TO 16 MM SHAFT THAT CAN SPIN UP TO 75,000 RPMS? IS THERE SUCH A BEARING. WAS PLANNING ON INSTALLING BEARINGS ON A CUSTOM BUILT TURBO CHARGER WITH A 140MM INDUCER AND 184MM EXDUCER ON THE COMPRESSOR. IT HAS A 162MM INDUCER ON THE EXHAUST WHEEL AND 150MM EXDUCER. WAS LOOKING TO MAKE IT INTO A BALL BEARING TURBO FOR DURABILITY REASONS. THANKS FOR ANY INFO. WAS WONDERING IF ANYBODY HAS ANY EXPERIENCES WITH CONVERTING A TURBO TO BALL BEARING AND TROUBLES THEY HAVE ENCOUTERED.

metiz
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Re: LOOKING FOR CERAMIC BEARINGS OR A 16MM SHAFT

Post by metiz » Sat Nov 07, 2009 11:11 pm

Don't know anything about those ball bearings but I do know where the capslock button is: On the left. It has "Caps lock" written on it.

Oh look, there it is!
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ace_fedde
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Re: LOOKING FOR CERAMIC BEARINGS OR A 16MM SHAFT

Post by ace_fedde » Sun Nov 08, 2009 1:16 am

I also don't know much about those ball bearings but I do know it might be better to try to find info in the Gas Turbine forum. I even think the info you want is already there.
Fedde
Your scepticism is fuel for my brain.

racketmotorman
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Re: LOOKING FOR CERAMIC BEARINGS OR A 16MM SHAFT

Post by racketmotorman » Thu Nov 12, 2009 12:16 am

Hi Steve

First off , where are you located ??

Secondly , what sort of rotating assembly are you using ??

Is it an ABB turbo rotor?? .............if so , is it a high temp turbine or a low temp diesel one ??

Thirdly , with an 188mm comp exducer , you'll only be spinning her ~48,000 rpm max before you start to overspeed her , 48K will produce a tip speed of ~1500 ft/sec and ~40psi of compressor discharge pressure , at 75,000 rpm you'd be theoretically running a comp tip speed of ~2370 ft/sec , you'd never get to that rpm , the compressor wheel would have split in two and probably gone thru the housing by 60,000 rpm .

Now comes the difficult part :-((................a turb rotor thats designed for "brass bushes" with their inherent damping qualities doesn't always work well with ball bearings , having spent a few years destroying bits and pieces doing what you intend doing, http://www.racketmotorman.turbinebuilder.com/ ..........I'm heading back to brass bushes and standard rotor bits .

There is also heat transfer problems( soakback) between the turb and ball bearings without the large lube flow that the brass bushes normally have.

Also there can be thrust bearing problems without high strength (M50) steel raceways due to the air pressure loadings on the rear wall of the compressor wheel when there isn't a compensatory pressure force on an axial turbine wheel , a radial inflow turbine wheel doesn't do much balancing of pressure loading .

If you want durability , stick with the brass bushes , ball bearings help with initial spoolup times , but once past 30% rpm the differance between balls and brass is irrelevant .

The large turbochargers on marine diesel engines as well as railroad engines use brass bushes , the ABB marine turbos are expected to produce >30,000 hours of work between overhauls .

Cheers
John

ace_fedde
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Re: LOOKING FOR CERAMIC BEARINGS OR A 16MM SHAFT

Post by ace_fedde » Thu Nov 12, 2009 11:10 am

ace_fedde wrote:I also don't know much about those ball bearings but I do know it might be better to try to find info in the Gas Turbine forum. I even think the info you want is already there.
Fedde
O.k. for people who don't understand my remark above, this thread was in the "Want to join?" forum and is now moved to here.

As you see, now that it is in the right forum, you get right answers from people who know (unlike me :wink: )

Fedde
Your scepticism is fuel for my brain.

andy88
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Re: LOOKING FOR CERAMIC BEARINGS OR A 16MM SHAFT

Post by andy88 » Wed Jun 16, 2010 4:03 am

hahahah

thanks caps lock pic was great :D
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ball bearings is in my body>>> :arrow:

falcon_jet
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Re: LOOKING FOR CERAMIC BEARINGS OR A 16MM SHAFT

Post by falcon_jet » Thu Sep 23, 2010 3:35 pm

Hello there, we have hi speed ceramic bearings here for 1/2" shafts. These can be spun up to 100k.Please let me know if you need further info.

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