TurboVac 50 troubleshooting

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NicholasNiski
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TurboVac 50 troubleshooting

Post by NicholasNiski » Sat Sep 21, 2019 4:32 pm

Hello, my name is Nicholas and I am an aspiring fusioneer. I’m still working on the vacuum phase of my fusor but I ran into an issue. My foreline pump can get to give-or-take below 50 microns in around 4-5 minutes.

My issue is that when I turn on my turbopump, a turbovac 50 with a turbotronik nt-50 controller, it spins for approximately 2 minutes and then the controller displays fail and turns the pump off. The pump does spin up, and there is a pressure increase in the foreline, so it does do *something*.

I have tried isolating the pump by putting my viewport on it, I have also switched around the wires from the controller to the pump(it didn’t come with any) but it still doesn’t spin up all the way

When the pump spins up, it doesn’t rattle or make lots of noise, just a few occasional chirps in addition to the buzzing of the motor when it accelerates.

In the manual it said that the fault light is turned on by a temperature sensor in the pump, but i can’t check that without disassembly.

Is this ultimately caused by shot bearings, or could something else make it turn off?

Victor Gonzalez
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Re: TurboVac 50 troubleshooting

Post by Victor Gonzalez » Sat Sep 21, 2019 7:27 pm

Turbo temp.png
turbo temp2.png

ChrisNiski
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Re: TurboVac 50 troubleshooting

Post by ChrisNiski » Sat Sep 21, 2019 8:49 pm

Thanks, we saw those.
I don't think it's overheating since the blower is running and it only runs for ~2 minutes at a time. It doesn't feel hot to the touch either. According to the forevacuum gauge the pressure is well within spec as well.

We were just curious if anyone had experience with this pump and if some other fault could be causing this, like some oil contamination from the previous owners.

Rex Allers
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Re: TurboVac 50 troubleshooting

Post by Rex Allers » Sun Sep 22, 2019 10:14 am

Seems there are two of you Niskis.
Please read the rules you agreed to here...
viewtopic.php?f=47&t=10508#p69690

There was sort of an introduction, but in the wrong place. Please do your introduction posts where they belong.
Rex Allers

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Dennis P Brown
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Re: TurboVac 50 troubleshooting

Post by Dennis P Brown » Mon Sep 23, 2019 9:03 am

When you say you switched around controller wires - what!? Turbo's require very specific connections and one can't switch any wires around and get any results. Random acts like that can really damage a turbo/controller! Get the proper wiring or don't do that!

Some turbo's monitor current load. If the bearings are no good, then the current draw on the turbo is seen as too high and the unit shuts down - never overheats. Measure the current draw by the unit and compare to its known value (found in documentation.)

ChrisNiski
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Re: TurboVac 50 troubleshooting

Post by ChrisNiski » Mon Sep 23, 2019 1:42 pm

Based on the schematics from here: https://hackaday.io/project/156682-open ... controller
the controller uses a simple 4-channel cable, with 3 phases and a ground for the motor.
Rotating the phase pins was done in case the motor tried to communicate with the controller on a dedicated pin, and they weren't in the correct order.
We'll take a look at the current drawn, that sounds like a good idea.

John Futter
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Re: TurboVac 50 troubleshooting

Post by John Futter » Mon Sep 23, 2019 7:51 pm

OK so its a Leybold pump
there are at least two differing makers with turbovac 50's
there is no temp sensor in the leybold
Is the pump turning the correct way
this can be done with the pump at atmosphere and disconnected from the system observe turning direction looking down into the top of pump
if turning the wrong way exchange any two phase wires to correct
controllers moniitor winding current and terminate runup if too much this is caused by buggered bearings
home made controllers like the one I posted a few years ago can be adjusted to allow more current during spin up
typical power required is around 10 -15 watts at full speed at 10-6 millibar vacuum
power during run up can be up to 100 watts
I used transformer tap switching in my design to limit power at low speeds with the tap change at 500Hz during run up

edit
my turbo controller here
http://www.coultersmithing.com/forums/v ... ?f=12&t=83

ChrisNiski
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Re: TurboVac 50 troubleshooting

Post by ChrisNiski » Mon Sep 23, 2019 8:55 pm

We stuck the viewport on top of the pump, it looks like it's spinning the right way round (clockwise). The pressure at the foreline does jump up as well, which should mean that it's trying to move air out of the pump inlet.

Jerry Biehler
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Re: TurboVac 50 troubleshooting

Post by Jerry Biehler » Wed Sep 25, 2019 12:11 am

Im betting you dont have as low foreline pressure as you thing you do. The nt-50 will light fail if the drive does not see fast enough acceleration and that is usually from too high of pressure.

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