First ever Turbo experience

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.
Peter Schmelcher
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Re: First ever Turbo experience

Post by Peter Schmelcher » Sun Apr 12, 2020 1:57 am

The little turbo pumps can be cycled fast back and forth to atmosphere quickly and you can even get them with aerodynamic breaking vents. When these are used in a production setting that ends up as a lot of mechanical PV compression energy and things get hot, so they fan or water cool them.

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Richard Hull
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Re: First ever Turbo experience

Post by Richard Hull » Sun Apr 12, 2020 5:12 am

Fortunately, at shutdown of a fusor, there is no time critical period for stopping a spinning turbo at 90k rpm. It is a walk away and "pop the tab on a cool one" time. Of course, I could run the fan for grins and googlers.... It don't cost much in 'tricity.

Thanks for the added info on the fan usage in up-down rapid operations where they are used in time critical operations.

Richard Hull
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Jerry Biehler
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Re: First ever Turbo experience

Post by Jerry Biehler » Mon Apr 13, 2020 4:31 am

Even on stuff where you just leave it on you want a fan.

Dan Knapp
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Re: First ever Turbo experience

Post by Dan Knapp » Mon Apr 13, 2020 3:44 pm

I run a Varian TV-301 (300 l/s) turbo full time without a fan. I regularly monitor its temperature with an infrared thermometer, and it usually runs 52 degrees C. They offer an optional fan for this pump "for heavy duty use" whatever that means. My guess is that I would get longer bearing life running at a lower temperature, but the pump has well over six years running time on it and only sings a little.

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Dennis P Brown
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Re: First ever Turbo experience

Post by Dennis P Brown » Mon Apr 13, 2020 7:33 pm

Fans do help extent bearing life on turbos; considering how expensive most turbo's are, a rather good idea to add a fan.

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Richard Hull
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Re: First ever Turbo experience

Post by Richard Hull » Mon Apr 13, 2020 7:49 pm

As mine spins up I have to wear hearing protection (very annoying), but once at speed it's Ok. Spin down is equally annoying. Pumps fabulously though.
About 15 seconds into spin-up it passes through some resonant point that sounds nasty and vibratory for about 2-3 seconds and then mellows right out for the rest of the 60-80 second high pitched spin-up.
At no time do I hear contact scrapes or bearing noise. That resonant point sounds wicked, though. Of course it is mounted and bolted directly to a wood table. (sounding board)

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

Jerry Biehler
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Re: First ever Turbo experience

Post by Jerry Biehler » Wed Apr 15, 2020 12:05 am

I fried the bearings on my TV-301 on my SEM by running it without the fan, wont make that mistake again.

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Re: First ever Turbo experience

Post by Dan Knapp » Wed Apr 15, 2020 11:11 am

I suspect that the SEM application would be considered “heavy use” with frequent cycling. I have run these turbos on mass spectrometers under constant vacuum for years before bearing changes were needed. Fusor use might be considered “medium” or “heavy” depending upon how much cycling of pressure one does. A fan is easy enough to install to play it safe. Some older turbos I have used had water cooling, which is more of a pain.

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Richard Hull
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Re: First ever Turbo experience

Post by Richard Hull » Wed Apr 15, 2020 2:44 pm

Mine has both water and fan capability, (seen in photos first page) neither of which I will use. I have run the Turbo for three hours straight and the motor bearing base is ambient. That is a very long run. I would call a fusor near a zero use device from my stand point as I tend to run a working fusor like fusor IV about 6-10 times per year with no more than 5 hours run time per operation. For the average turbo in a vacuum system, I would think that is near zero run time.

This is why I used a diff pump since 2004. I just could not justify the cost of a Turbo for such intermittent use.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

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