Leybold turbovac 150CSV bearing problem

Every fusor and fusion system seems to need a vacuum. This area is for detailed discussion of vacuum systems, materials, gauging, etc. related to fusor or fusion research.
Johan Reinink
Posts: 14
Joined: Thu Nov 17, 2016 12:43 pm
Real name: Johan Reinink
Location: Enschede, The Netherlands

Leybold turbovac 150CSV bearing problem

Post by Johan Reinink » Thu Nov 24, 2016 4:09 pm

All of the turbo's I got have bearing problems. I'm starting with the smallest, a Leybold 150CSV. Starting it up (borrowing the controller from the university, I'll have to build my own) revealed it doesn't run smoothly:
https://youtu.be/a9WT8MuMGpw
My guess is that the bearings have worn out. Note that this pump have been out of use for at least a few years, but I don't think that a lack of lubrication would cause these sounds. During transport I also lost most of the oil (whoops) so I'll have to source some new.

It is a very similar pump to this one:
https://youtu.be/jL0fXUZ4wFQ
I already ordered some quality ceramic skateboard bearings so that I can hopefully do the repair in one go and not have a dissasembled turbo waiting for parts. I'll attempt the same repair as in the video but it would be nice if someone can confirm it's probably the bearings that are broken, not just unlubricated. Other tips an comments are definitely welcome as well. And if someone has turbopump oil I'm interested.

Jerry Biehler
Posts: 727
Joined: Tue Nov 24, 2009 8:08 am
Real name:
Location: Beaverton, OR

Re: Leybold turbovac 150CSV bearing problem

Post by Jerry Biehler » Sat Nov 26, 2016 2:40 am

Skateboard bearings? Nope, nope, nope, nope. Bearings are not all the same. And just because they say ABEC 7 on the package, they are probably not. Dont listen to that guy in the video, he is full of crap.

And yes, your bearings are shot. Dont bother adding new oil, it wont make a difference.

Talk to Alpine bearing about replacements: http://alpinebearing.com/bearing-categories/ball-2/
They make the bearings sold in third party rebuild kits.

John Futter
Posts: 1214
Joined: Thu Apr 22, 2004 2:29 am
Real name:
Contact:

Re: Leybold turbovac 150CSV bearing problem

Post by John Futter » Sat Nov 26, 2016 10:29 pm

original bearings for these are Barden brand
http://www.bardenbearings.com/content.b ... /index.jsp
and these bearings are run at maximum speed or slightly above their maximum

Johan Reinink
Posts: 14
Joined: Thu Nov 17, 2016 12:43 pm
Real name: Johan Reinink
Location: Enschede, The Netherlands

Re: Leybold turbovac 150CSV bearing problem

Post by Johan Reinink » Sun Nov 27, 2016 7:51 pm

How much do the Barden or Alpine bearings cost? Turbo's in unknown condition go for sub 100 euro, if a bearing costs more than that I might as well wait for a second turbo to show up on ebay and harvest a good bearing if only one seized and then have spare parts as well. If I want to buy a new bearing I'll do it for my Pfeiffer TMU-521, that's a pump worth rescuing I think.

I'm perfectly willing to risk turning the pump into aluminum soup. The guy in the video may be full of crap but he did get his turbo up to full speed with a skateboard bearing, so unless he's flatout lying I don't see a problem. I'm simply taking the chance that the original bearings were overdimensioned and that I can do with less, and that high quality skateboard bearings are overdimensioned and that I can get away with a good one. Even if it eats a bearing per month of running time it's fine, I won't be running it that often or long anyway.

According to here:
https://www.pfeiffer-vacuum.com/en/know ... principle/
The pumping speed scales linear with rotation frequency and the compression ratio exponentially (approximately). So if at 60k rpm I get 150 l/s at a compression ratio of 10^9 (for N2) then running the turbo at 40k rpm would give 100 l/s at a compression ratio of 10^6. Still plenty of pumping speed and I plan to use a double stage rotary vane vacuum pump, that should create a low foreline pressure and allow a lower compression ratio. I think that would be enough for a small o-ring sealed system to reach somewhere between 10^-4 and 10^-5 and it would reduce the stress on the bearings.
Last edited by Johan Reinink on Sun Nov 27, 2016 10:10 pm, edited 1 time in total.

Jerry Biehler
Posts: 727
Joined: Tue Nov 24, 2009 8:08 am
Real name:
Location: Beaverton, OR

Re: Leybold turbovac 150CSV bearing problem

Post by Jerry Biehler » Sun Nov 27, 2016 10:06 pm

Never swap bearings, it is not worth it. Bearings are often damaged just removing them and you have no idea of the condition they are in. Bearing work of this kind really needs to be done in a very clean environment, ideally a laminar flow hood or a clean room. Worst case a room with a HEPA air filter. All it takes is a spec of something to kill a bearing.

Why risk turning a pump into scrap for cheap bearings? That makes no sense, do it right, once. If you are not willing to do it right maybe you should just get a diffusion pump.

Overdimensioned? You mean over speced? No, engineers know exactly what they need to use for the application.

Just use the right bearings. Contact the company and see what they cost.

Johan Reinink
Posts: 14
Joined: Thu Nov 17, 2016 12:43 pm
Real name: Johan Reinink
Location: Enschede, The Netherlands

Re: Leybold turbovac 150CSV bearing problem

Post by Johan Reinink » Sun Nov 27, 2016 10:50 pm

It makes perfect sense. I can swap the bearings in a clean environment, no problem. Diffusion pumps are practically unavailable second hand, their oil is expensive to get, probably could buy me a correct bearing or two. Not a cheap option even if available. Turbo's in a condition like mine are cheaper than a replacement bearing. It has been demonstrated it can work, so even if it isn't a guarantee I'll take my chances.

I'll see if I can get a quote from Alpine but shipping + tax alone would probably make it an expensive option compared to just getting another turbo in questionable bearing condition. Yes I mean overspec'ed, but if turbo's survive high gas loads and even atmospheric inrush I say I may get away with a lesser quality bearing if I don't let that happen.

Sure this isn't the "right" way to do it, but I'll direct good efforts to a pump worth the effort, not this old one. The "right" way would be to scrap the pump, which is how I got it in the first place. It would be economically stupid to get an expensive bearing for a turbo like this, it would be better to cut the turbo in 2 and make a display pieces out of it and buy a new one.

Jerry Biehler
Posts: 727
Joined: Tue Nov 24, 2009 8:08 am
Real name:
Location: Beaverton, OR

Re: Leybold turbovac 150CSV bearing problem

Post by Jerry Biehler » Mon Nov 28, 2016 5:25 am

Bearings are often damaged when you remove them and they tend to take a set when they are installed. Plus you have no idea what the history of the bearing is, it may be junk before you even tear it apart.

Diff pumps are easy to get, there are usually a bunch on ebay. There are a lot of fluids available for them, you can even use mechanical pump oil as the working fluid.

Companies rebuild and sell used turbos all the time, there are many vendors. If you have a machine that has one in it and it grenades you are going to need the same model because you are not going to want to change out the drive as well since they are often tied into the system. Youre looking at about $1700 for a rebuilt unit of the same model as yours.

Johan Reinink
Posts: 14
Joined: Thu Nov 17, 2016 12:43 pm
Real name: Johan Reinink
Location: Enschede, The Netherlands

Re: Leybold turbovac 150CSV bearing problem

Post by Johan Reinink » Tue Dec 06, 2016 6:22 pm

I appreciate your feedback Jerry but you're not really reading what I'm posting here. If you had read the thread you'd know this turbo it not from some machine, I don't even have my own controller, I borrowed it. This turbo is expendable. $1700 is beyond my budget and certainly not logical to spend on such an old turbo if there's choice. I contacted Alpine bearings for a possible replacement bearing for my Pfeiffer TMU-521, it was $175, which after shipping & taxes can easily be 250 euro. That TMU may be worth it, not this old 150CSV, of which I estimate the value around 50~70 euro, so a skateboard bearing is economically fitting. I'd appreciate it if you'd understand this and be a little more supportive.

Even a 2~3 euro 608 size SKF bearing has a limiting speed of 48k rpm, close to the 50k rpm of this turbo (not 60k as I previously thought). I still plan to go for lower, something like 30k rpm if there's no resonance there.
There's the guy using skateboard bearings succesfully and here on the forum I can remember reading about someone blowing up $250 in quality bearings. There are simply not that many examples that demonstrate how picky turbo's are when it comes to bearings (something I don't want to risk for this old turbo). My repair will add one, it'll be a learning experience, either to confirm that the skateboard bearing guy is "full of crap" or to confirm it works, we should be happy obtaining either result. I'll get a proper turbo or a diff pump when I actually need a vacuum without messing around.

Jerry Biehler
Posts: 727
Joined: Tue Nov 24, 2009 8:08 am
Real name:
Location: Beaverton, OR

Re: Leybold turbovac 150CSV bearing problem

Post by Jerry Biehler » Wed Dec 07, 2016 2:26 am

Im not saying spending $1700 to buy a pump, I am saying spend the money to repair it correctly and then you will end up with a pump that is worth considerably more than what it is now.

Rex Allers
Posts: 178
Joined: Sun Dec 30, 2012 8:39 am
Real name:
Location: San Jose CA

Re: Leybold turbovac 150CSV bearing problem

Post by Rex Allers » Mon Sep 18, 2017 8:07 am

I just got one of these Leybold Turbovac 150CSV too.

I'm wondering if Johan ever tried to rebuild his. Sounded like he was going to try to replace bearings, possibly with cheap ones. I'd be interesting to hear good or bad results if he did try to rebuild.

So, on mine. I want to test it but can't yet because the oil cup that feeds the bearings is empty. I have the old driver box to feed it but can't see trying to spin it up, even part way until I have oil in it.

Here's a little bit about these old turbos. Maybe it will be useful for others. These seem to be about 30 yrs. old. I get that from date codes on parts in the drive box which look to be 86 or 87. Yikes! That seems to be quite old for a high-rpm spinning device to still be alive. But won't know until I try.

The docs I have been able to find on the web are for the 151 version. That one seems to be newer and has greased bearings where the 150 uses oil lubrication. The 150 I have clearly has a plastic cup on the bottom to hold oil for the bearings, but it is empty. With no proper documentation I don't know what oil might work. Anyone have docs for these old Leybold 150/360 pumps?

The second link to youtube in the first post of this thread describes rebuilding a similar pump. Much of that video is considered blasphemy by some commenters here. FWIW he used a hydrocarbon (not silicone) based diff oil as his cost-effective lube for the bearings.

I did look for hydrocarbon diff pump oil at the vacuum vendors I know of and didn't see any. Seems all offerings were the newer silicone stuff. I also searched for Turbo bearing oil. Didn't find much. Seems most turbos have gone away from oil lubed bearings. Grease or magnetic seem to be current designs. But, the one exception was that I did find Turbo Pump Oil at Duniway. Here's the link
https://www.duniway.com/catalog/supplies/turbo-pump-oil

I guess I'll probably try that. I got the MSDS for that Duniway oil and it says this:
Description: Full synthetic lubricant on ester basis
Components: 90-95% neopolyolester, 5-10% additives

Density @ 20C = 0.947 kg/l
Viscosity: kinematic @ 40C = 10.5 mm^2/s
( 1 cSt = 1 mm2·s-1 )

There's a Wiki page for Polyolester oil (POE oil). Seems it is big for refrigerant pumps. One characteristic mentioned there is that they are hygroscopic in nature. That doesn't seem great for a vacuum pump but I don't really know. I also don't know if the neo- in the MSDS changes anything. Some other links seemed to imply another application for these kinds of oils was turbines, like jet engines. Maybe that would be another source for an oil that might work, but I didn't find any that looked worth trying.

Anyone have any other input about oil to put in this thing? From the size of the cup and guesstimate subtracting for the metal in the middle, I think I need around 30 cc of oil to fill it.

For reference, here are two pictures of the old pump I have.
Turbovac 150CSV.jpg
Turbovac 150CSV
Turbovac oil cup.jpg
Turbovac oil cup
Here are a few notes from looking at the pump.
- The Backing pump connection is KF-25
- The electrical drive connection is octal pins, like the base of an old vacuum tube but recessed in a metal cylinder.
- The vent connection is KF-16 diameter but the center recess is too small to take a standard KF-16 centering ring. (Arrgh! Why?)

Any comments on these old Turbos or the oil I need are welcomed. I'd especially like to hear from Johan about if he tried to rebuild his pump with bad bearings.
Rex Allers

Post Reply