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Electronic Tubes

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BobBB-8

New Member
I have a problem finding information on some tubed I have
I have 6 big National Tubes
NL-6989-NE
The Tubes are new and because of their size I thought I could make some kind of cool display. The tube has a high voltage cap on the top and printed on the base along with the tube numbers is "National Power Tube"
and has 4 "U" shape connectors.
They are 9 inches tall and new.
If anyone has an idea for a cool DIY project, or knows what it was used for please help.
 

zahwi

Member
They are triodes used in industry to generate about 100W radio frequency for plastic welding, induction heating, medical equipment, etc. I used them 20 years ago and they are still in use.
JimB already has given you the best idea what to do with them.
 

gary350

Well-Known Member
I worked in industry for 40 years there is still a lot of old equipment around. Some factories seem to believe it is best to keep the old machine running because it is paid for. Better than buying a new $300,000. machine. The older the equipment gets and the more rare the tubes get and the higher the prices get.

For several years you could buy an SLC150 programmable controller for $25 used they were once $1000 new but now the price is up to $500 used. Pay the ransom or buy a new $300,000. machine.

I once had 100s of old industrial tubes that I tried for 25 years to find projects for. I finally sold them all for a nice ransom on ebay.

The old stuff is big and heavy and the power supply is bigger and heaver. A 100 watt relay is not much, you can probably do that with a mosfet. It would be nice to know what that tube was used for back in the day when it was popular.

I still have several NL-7171 ignitron tubes rated 5000 volts DC 30,000. AMPs. They are capacitor bank discharge tubes sorta work like your relay tubes only much more power. Excellent for building an EMP or magnet coin crusher or multi 50 tip spot welder.
 
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DerStrom8

Super Moderator
Most Helpful Member
I still have several NL-7171 ignitron tubes rated 5000 volts DC 30,000. AMPs. They are capacitor bank discharge tubes sorta work like your relay tubes only much more power. Excellent for building an EMP or magnet coin crusher or multi 50 tip spot welder.
How much $$? :D
 

gary350

Well-Known Member
Not sure yet if I want to sell these. We are going to set up a test for the NL-7171 tubes to see if they are good. I don't know anything about these tubes, some could be used, some might be new, some could be 50% or 95% used. Ignitrons will work good as new right up to the very end. Often the factory log book tells maintenance when to change the tubes before they give out so they don't loose product on the assembly line waiting for maintenance to repair the equipment. Even if a tube is 95% used up that is good as new to me I wont be using it as much like a factory would 40 hours a week for 3 shifts. I am building a rail gun the NL-7171 will be good for this project cap bank full charge is 270,000,000. watts. I don't want to be any closer than 100 feet when I push the button.
 
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