Old Turbotorr Pump Servicing

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.
Post Reply
Jeremy Adams
Posts: 26
Joined: Mon Aug 18, 2014 9:08 pm
Real name: Jeremy Adams
Location: Chicago Ill

Old Turbotorr Pump Servicing

Post by Jeremy Adams »

Hi everyone,
I have an old turbotorr sargent welch 3131 sitting in my garage. The pump does 600L/sec and makes an ultimate vacuum of 5*10^-8 torr which is fairly strong. It's an old model and hard to come across. I was trying to take it apart to make sure the bearings are good and clean it out. However it's really hard to take apart! The nut on the top of the pump has an arrow indicating off. I took off the bottom of the pump to grip the other end of the rotor so I could use two wrenches to hold in place and twist off the top nut. This didn't work because it was on super tight. Any ideas?

I also need to get a power supply for it which is an entirely different challenge I'll post more about soon. Basically I can't find the 3131 PS for my pump being sold at all. So I might have to get a different power supply for a similar model of the same brand like a 3133 PS and attenuate the high frequencies using a passive low pass filter to make it suitable for my pump.

-Jeremy
Attachments
Sargent welch 3131
Sargent welch 3131
Bottom of the vacuum / Tail of the rotor axis
Bottom of the vacuum / Tail of the rotor axis
Top of the Vacuum (see middle nut with "off" arrow)
Top of the Vacuum (see middle nut with "off" arrow)
Doug Browning
Posts: 156
Joined: Sat Mar 10, 2012 9:19 pm
Real name: Doug Browning

Re: Old Turbotorr Pump Servicing

Post by Doug Browning »

From what I can just make out of the top shaft thread in the picture, looks like the "off" arrow is pointing the wrong way. Check the thread carefully to see which way actually gets the nut off.
Jerry Biehler
Posts: 975
Joined: Tue Nov 24, 2009 3:08 am
Real name:
Location: Beaverton, OR

Re: Old Turbotorr Pump Servicing

Post by Jerry Biehler »

STOP! Don't take it apart unless you have to. Many of these old pumps required fixtures to work on. If it spins freely now dont mess with it, there is nothing visual that will tell you the ultimate life or condition of the bearings otherwise and there is a better chance of ruining them if they are good.

That being said, I would not invest much into an old pump like this.
User avatar
Dennis P Brown
Posts: 3160
Joined: Sun May 20, 2012 10:46 am
Real name: Dennis Brown

Re: Old Turbotorr Pump Servicing

Post by Dennis P Brown »

Agree 110% with Mr. Biehler; also, those bolts with the apparent access "holes" around them indicate, at least to me, that a special tool is needed to "break free" those nuts. Again, a complex job or so it appears to me. I just feel this isn't a job to do unless the bearings have failed anyway. Besides, even if you succeed, many turbos have a special order for the drive rotor blades and if they are assembled wrong, it will not work. Since the device still works extremely well, leave it alone. Some turbo's (like my little cheap one) DO allow you to inject bearing oil into the unit via an outside vacuum tight access port (the oil for turbo bearings is very special so without that oil, exactly what do you achieve if you do access the bearings?) So check on line for a manual for details; there was one available for mine despite my unit being very old and a tiny. Search extensively and I would suggest that you not service the until at least you have instructions on how "to do the job correctly". Otherwise, you will end up with a pile of junk ... .
Andrew Seltzman
Posts: 815
Joined: Sun Feb 01, 2004 8:02 pm
Real name: Andrew Seltzman
Contact:

Re: Old Turbotorr Pump Servicing

Post by Andrew Seltzman »

Almost all of the sargent welch pumps run 3 phase AC at 1500Hz
Andrew Seltzman
www.rtftechnologies.org
Doug Browning
Posts: 156
Joined: Sat Mar 10, 2012 9:19 pm
Real name: Doug Browning

Re: Old Turbotorr Pump Servicing

Post by Doug Browning »

The ring of threaded holes around the top shaft is (I suspect) for balancing the rotor (aka: tire weights). Notice the insert in one of the holes. If it is disassembled, you not only have to get the order of the parts correct on re-assembly, but the rotational phase of each disk. Probably best left alone unless something has definitely failed.
Jeremy Adams
Posts: 26
Joined: Mon Aug 18, 2014 9:08 pm
Real name: Jeremy Adams
Location: Chicago Ill

Re: Old Turbotorr Pump Servicing

Post by Jeremy Adams »

Thanks for the advice! Sounds like I'll just leave it alone for now and let it be. Should work fine since it spins well. Also the pump takes 420Hz, 25v, and 12A for its power supply
Jerry Biehler
Posts: 975
Joined: Tue Nov 24, 2009 3:08 am
Real name:
Location: Beaverton, OR

Re: Old Turbotorr Pump Servicing

Post by Jerry Biehler »

Jeremy Adams wrote:Thanks for the advice! Sounds like I'll just leave it alone for now and let it be. Should work fine since it spins well. Also the pump takes 420Hz, 25v, and 12A for its power supply
At that voltage you might be able to use a brushless motor driver for RC helis/airplanes.
Andrew Seltzman
Posts: 815
Joined: Sun Feb 01, 2004 8:02 pm
Real name: Andrew Seltzman
Contact:

Re: Old Turbotorr Pump Servicing

Post by Andrew Seltzman »

You are correct, the operating specs are 420Hz, 25v, and 12A for its power supply.
http://www.rtftechnologies.org/Design/A ... -specs.PDF

An RC brushless controller won't work, since they are designed for permanent magnet brushless motors (so it can use back EMS sensing for sensor-less operation), and this is an induction motor. A variable frequency drive (VFD) should work well though.
Andrew Seltzman
www.rtftechnologies.org
Post Reply

Return to “Vacuum Technology (& FAQs)”