Testing Seiko Seiki 300 turbo pump

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Chuck Sherwood
Posts: 36
Joined: Sat Jun 05, 2021 3:57 pm
Real name: Chuck Sherwood
Location: Naperville, IL

Testing Seiko Seiki 300 turbo pump

Post by Chuck Sherwood »

I recently acquired a Seiko Seiko 300 series turbo pump and controller. It is a full magnetic levitation bearing pump and therefore requires two 12 volt batteries for backup power. It is also rated for 100 VAC, so I tested with a variac. Last date on the battery tray was 1990 and I knew the previous owner so I am pretty sure it has been setting on the shelf for 30 years. Here are some pictures of what it looks like as received.
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I opened it to see if there are any internal ways to change the power voltage. Nothing obvious and quite an OMG moment. You can see the empty battery tray. I installed two 12V 7AH batteries.
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The connecting cable is quite populated. I was told that all three components, controller, pump and cable are tuned and matched at the factory and the serial numbers need to match. Yes they do. If they do not, there is a field tuning procedure.
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I ordered a ISO100 to KF50 adapter for some testing. Here is a simple setup on the bench for a test run. I have been told that needs to be securely mounted for a bump while running will kill it.

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First run was stressful. It worked ok for a while but started making bong noises. Apparently this is the sound of the magnetic levitation system releasing and letting the rotor contact the mechanical "touchdown" bearing. I increased the input voltage from 100 to 108. AKA 90% of line voltage on the variac.

It has made a half dozen test runs. The rotor takes 9 minutes to reach full speed. After a number of pump downs, it will get into the mid "6s" a couple minutes after reaching full speed. It has to coast down and the manual recommends a vent to 5 torr to slow it down. Therefore another slow vent valve is required; yet another project to make.

It works well, pumps well, but I'm still scared to use it much. One false move, like an air breach and it toast. I will probably use the Pfeiffer for a while before setting this one up.

I hope you enjoy to tour.
chuck
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Richard Hull
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Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: Testing Seiko Seiki 300 turbo pump

Post by Richard Hull »

I, like you, would be afraid to run this thing in real life. In its first life, (when new at $10,000 plus), it must have been mounted in a steel frame set in concrete. Thanks for the tour.

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Jerry Biehler
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Joined: Tue Nov 24, 2009 3:08 am
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Location: Beaverton, OR

Re: Testing Seiko Seiki 300 turbo pump

Post by Jerry Biehler »

Nice pump, a lot of these seikos were used on SEMs and FIB because of the maglev. You can run them off 120v no problem. The battery is there to keep the rotor levitated in the case of a power loss. The touchdown beating is only rated to take a couple high speed landings, I think 5.

They are interesting beasts. That first time you hear the rotor drop is quite a surprise. Otherwise you can treat them like any other turbo, you dont need to slow them down, you can just let them spin down naturally, they do have an internal dynamic braking system. Without it they take about 8 hours to stop at high vacuum.

I have an Osaka maglev pump on my big chamber. Its a 2000l/s one with a 200mm ISO flange.
Jerry Biehler
Posts: 975
Joined: Tue Nov 24, 2009 3:08 am
Real name:
Location: Beaverton, OR

Re: Testing Seiko Seiki 300 turbo pump

Post by Jerry Biehler »

Oh, and when they are on SEMs they just hang from a ISO-100 flex connection with rubber vibration isolators. There is not a whole lot to worry about on a pump this size. The BIG ones you need to worry about. They will rip the bolts right out of the conflat or ISO flange.
Chuck Sherwood
Posts: 36
Joined: Sat Jun 05, 2021 3:57 pm
Real name: Chuck Sherwood
Location: Naperville, IL

Re: Testing Seiko Seiki 300 turbo pump

Post by Chuck Sherwood »

This pump has provided me membership in elusive "Club 7". After running for several hours today using this setup. I achieved pressure of 8E-7 Torr. I've been playing with diffusion pumps for years and could never get below about 3E-6
cs
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