TMP Diagnosis

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.
Jackson Oswalt
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TMP Diagnosis

Post by Jackson Oswalt » Tue Aug 08, 2017 3:25 am

Hello!

As I've mentioned in some of my previous posts, I am a proud owner of a turbo molecular pump. I got the pump off of eBay for $160 and the drive unit from a YouTube channel called "Gooferking Science" for $100. He had the same model pump as I before he broke it in a freak accident. Thankfully, the drive unit was fine and he sold it to me along with all the cables.
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Turbo Molecular Pump (side)
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Turbo Molecular Pump (top)
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Turbo Molecular Pump Drive Unit (front)
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Turbo Molecular Pump Drive Unit (top without cover)
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Turbo Molecular Pump Drive Unit (side without cover)
Sound like a bargain for a TMP, doesn't it? Well for the most part it is. There are zero noticeable scratches on the actual pump, the blades spin quite well when I push them with my finger, and all the o-ring are in great shape. But how does it run? There's the catch. I've had the pump since February, and I still haven't been able to get it to work. The drive unit powers up, the "ready" light comes on, I flip the switch and the "accelerate" light comes on, but it doesn't go. It just sorta stumbles. It tries to speed up, but then it stops. If I leave it to struggle like this, the fuse will eventually blow. So, in this post I'll say everything I know with the hope that someone has an answer. Something tells me this will be rather long, so bear with me.

The beginning:

The only thing suspicious about the shipment and purchase was the day the pump arrived. It was soaked in oil. I guess the pump had flipped upside down during shipment and all the oil had spilled out. Could it be possible that the spilled oil could have clogged the motor or something? That would explain the symptoms, but that doesn't seem likely. Since then, the pump has been dried off and stocked with new oil. For anyone that might be thinking of getting a TMP, you should know that oil is $50+ for 3oz.

The fuse:

The original problem that I found with the TMP was that it was missing a fuse. "Gooferking Science", the guy who sold it to me, explained that he had taken it out to use on his Variac. No problem, I'll just buy another one and it'll work, right? Nope. After at least $50 had been spent on various fuses, I came up with zero results, other than that it started stumbling as I explained above instead of just not doing anything. I reached out to many people: Gooferking Science, other people on eBay selling the same drive unit, and Rigaku (who has denied making the pump despite the fact it says "Rigaku" in ten places). In the end the only answers I got were "I don't know" or a diagram of some random TMP drive unit. After all this, I started to think maybe the fuse wasn't the problem.
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Fuse Holders
The switch:

Because this technology is from 1995, it's quite difficult to locate all of the pieces. The most important thing I couldn't find was the switch that starts the acceleration. Fortunately, there's a rather simple way to fix this. As I learned from Gooferking, you can stick to leads of a switch into the bottom two holes of the "CN4" ports. You can see it in the picture below. However, despite the crudeness of this switch, I seriously doubt this the failure point. Gooferking used the exact same switch in the exact same way, and it worked perfectly. In fact, he has a video about it here: https://m.youtube.com/watch?v=A0v3tNCLqkA. So, I don't think it's the switch.
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Ports "CN4" and "CN2"
The roughing pump:

As of now, I believe this is the most likely place of failure: the roughing pump. My roughing is a Robinair 15500. It's supposed to get down to 75 microns at most, which isn't very good considering that's it's lowest pressure in a leak tight, outgassing free chamber. Something tells me that the TMP can't start at whatever crappy pressure the pump draws. Another reason why this would make since is because Gooferking had a rather nice pump himself (as you can see in the video linked above).
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Pump Specifics
Now, for the fine details:

TMP Model: rtp300vrc
Year: 1996
Brand: Says "Rigaku". People at Rigaku want me to believe it could be a Varian.
Fuse 1 (for power to the drive unit): 15A. Came with the drive unit.
Fuse 2 (For power to the actual pump): 5A. Didn't come with drive unit.

That's all I got. I'm happy to answer any questions!

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Richard Hull
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Re: TMP Diagnosis

Post by Richard Hull » Tue Aug 08, 2017 5:48 am

Can't offer much assistance beyond asking if you took some of the photos lying down and some standing on your head.

Not a single image is oriented so that a person gravity locked to the earth can get a normalized view of what you have. In future, you might orient the images to appeal to those of us who walk and function upright on this planet. Just sayin'

I dare not suggest you are doing this deliberately, but given the reasonable conclusion that I don't think that given the random sample of images you have here that I would not get at least one single upright image in such a posting. (probability issue)

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.

John Futter
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Re: TMP Diagnosis

Post by John Futter » Tue Aug 08, 2017 7:08 am

Yep
I've sid Tooooooooo many times how to resize/ resample so the pics obey gravity
but the great unwashed who post and do not read,continue to do this much like the idiots who hold their cell phones the wrong way to video
ie
https://youtu.be/Bt9zSfinwFA

Sarvesh Sadana
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Re: TMP Diagnosis

Post by Sarvesh Sadana » Tue Aug 08, 2017 7:18 am

If you click on the pictures they will be oriented the correct way. It appears to be an issue with the forum software itself rather than the pictures (though I have noticed that some picture types work better than others -- PNG tends to work better than JPEG).

Sarvesh

John Futter
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Re: TMP Diagnosis

Post by John Futter » Tue Aug 08, 2017 8:30 am

Sarvesh
No it is not the forum software
The max size a picture can be is 1024 by 768 after that the board software starts doing things all on its own
Remember this site is free and content is paid for by Paul the Perfessor why upload way Too much resolution the end result is Paul pays and his generousity
may start to suffer
Just because you have the latest 12 terabyte camera in the recent hand implant --you do not not have to pollute the the storage with unneccessary gigabytes of wasted unrealizable picture content

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Richard Hull
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Re: TMP Diagnosis

Post by Richard Hull » Tue Aug 08, 2017 8:10 pm

John is right. The photos I put up are all oriented correctly, are JPEG, and rarely exceed 500kb each. They all come out right side up and stay that way when clicked on to enlarge.

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.

David Kunkle
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Re: TMP Diagnosis

Post by David Kunkle » Wed Aug 09, 2017 2:03 am

I see a TC in the first pic, but you make no mention of what pressure the roughing pump achieves? You mention 75 microns like it's the factory rating. A worn pump or a small leak would easily put the pressure outside the range where a turbo can operate.

I'm still trying to fathom how you spent $50 in fuses?
If your experiment needs statistics, you ought to have done a better experiment.

Ernest Rutherford

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Rich Feldman
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Re: TMP Diagnosis

Post by Rich Feldman » Wed Aug 09, 2017 7:33 pm

Just a few words about the photo size and orientation thing. I learned that recent smartphone & digital cam JPEG's generally include EXIF-format metadata. Jackson's fuse panel picture, for example, has lens, aperture, and shutter details. Also the camera model (iphone 7), exact date and time, and precise latitude and longitude of the fuse holders.

EXIF has a place for orientation of the cam when picture was taken, and maybe (independently) the desired orientation of the image for viewing.
There might also be image orientation details in OS-specific file attributes. It used to be that rotating a JPEG by 90 degrees was a lossy operation (as implemented in Windows Explorer, for example, which grayed out the rotate buttons if an image file's read-only bit was set).

Apparently, most of us see some of the "thumbnail" images in OP shown sideways (fuse panel) or upside down (rotary pump).
I find that if I click on one, the linked .php fetches the image and shows it the way Jackson intended.
But if I then save that image to file, or back up a step and "save target as" a file, the resulting jpg is oriented like the thumbnail
(probably fixed WRT the sensor in Jackson's iphone). Delving into the saved files, I found camera and exposure and geographic location, but nothing that looked like an orientation thing.

Right now it looks like this automatic rotation stuff isn't standard enough, or universal enough, to generally work across platforms.

I stand firmly in the camp which feels the burden is on the presenter, not to depend on new features that aren't mature.
Burden is _not_ on the forum software, or the individual reader, to update their software if it's less than (say) 5 years old.

Even when properly oriented, I think 4032 by 3024 pixel images are way too big for general posting, and not just because of the burden on Paul's server. Jackson's images would be no less informative 640 x 480 pixels.
1. Consider the burden on readers/viewers with a less-than-fast Internet connection, perhaps a marginal mobile link at their laboratory in the woods. Many of us have never streamed, or even wanted to download, a TV show or movie.
2. Consider readers/viewers with small screens. Automatic scaling, or easy panning around an image 8 screens wide, is like automatic rotation. Not universal enough to depend on readers having it or getting it.
My trouble-saving remedy of choice, when taking pictures for Internet forums that aren't mainly about photography: set camera to save pictures at much less than maximum resolution. It would be different if I were visiting Timbuktu for the only time in my life.
Mike echo oscar whisky! I repeat! Mike echo oscar whisky, how do you copy? Over.

Jackson Oswalt
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Re: TMP Diagnosis

Post by Jackson Oswalt » Thu Aug 10, 2017 10:41 pm

1. Thermocouple vacuum gauge is having some problems. Still working on it.
2. $5 per pack of fuses. 10 attempts. The 5A rating has proven to possibly incorrect, despite how strange it may be.
3. I apologize for the inconvenience of the upside down photos. The TMP is positioned on the back of my desk, so I had to flip my phone to take the pictures. However, you can simply click on the photos and they will orientate themselves correctly.
4. If it's ok with you, I'd appreciate being let off the hook for this post.mIt doesn't seem like I'm going to get any replies other than that the photos are upside down.

Again, I apologize for the upside down photos. It won't happen again.

David Kunkle
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Re: TMP Diagnosis

Post by David Kunkle » Fri Aug 11, 2017 1:58 am

Never heard of a Rigaku turbo. I looked at their site out of curiosity, and they obviously no longer make or sell turbos except as part of an instrumentation package. Maybe they used to sell turbos with their name on them long ago, but the manufacture was farmed out to Varian?

You said it was "soaked in oil" when it arrived. Did any oil get down into the vacuum inlet or outlet?

I'd get the TC fixed ASAP. Without it, you're working blind and just guessing that your vacuum is good enough to run a turbo and not ruin it.

Certainly appears to need a 5A fuse in the photo. Did it keep blowing fuses, and you just kept upping the amp rating on the next fuse until it stopped blowing?
I wouldn't attempt to run it again until you've pinpointed something. Next time something is liable to blow before the fuse, then you'll have a doorstop. ;)

My best guess is a short somewhere, or possibly oil on the rotors and stators would cause a lot of resistance when it's trying to speed up- assuming your vacuum isn't several hundred or several thousand microns.
If your experiment needs statistics, you ought to have done a better experiment.

Ernest Rutherford

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