Quickie: New paint for a Karl Klein DNG 6-22,5

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I recently got this Karl Klein DNG 6-22,5 blower (22 m3/min) I want to use for dust extraction. Unfortunately the seller spray painted the whole thing with zinc spray w/o telling or asking me. This is what I got out of the box: It appears that they at least stripped off parts of the old paint (maybe even sand blasted it?) but like I don’t like this look. So I gave it a quick new paint job, first I removed some of the zinc spray where it was not sticking properly.

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Repairing a Siemens Schuckertwerke AC Motor

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Disassembly Te screws of the bearing covers were completely sheared off, probably from vibrational damage. New bearings Replaced the old bearings with new SKF 6200-2RSH ones. Odd screws The screws holding the bearing cover were of an odd dimension, either imperial or something like M3.5. I decided to rethread the inner plate to M4, so I can use standard screws. To do this I used a 3.5mm reamer to clean up the hole and re-threaded it to M4.

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Voltcraft Power Supply Maintenance

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I got a couple older power supplies from the Voltcraft brand, so I decided to clean them up a little bit: 12V 2A - Replacing Selenium Rectifier This unregulated unit had a selenium rectifier that started smelling a bit sweetly, which is the smell of impending failure. I replaced it with a silicon rectifier and also added a short circuit current limiting resistor, as I dunno whether the transformer is short circuit proof.

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±340V, 170V DC Power Supply

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Built this the other day to have a more accessible higher voltage DC. The circuit is straight forward, a voltage multiplier giving ±340V off the 230Vac secondary of the transformer and another a half rectifier from the transformer’s 115Vac secondary to also provide 170V. I also added a small neon indicator to show whether the two main reservoir capacitors of the ±340V are still carrying a charge. The output is limited with power resistors.

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Repairing a SE.306.1-2 Power Supply

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I recently got this old power supply in an untested condition. It has an unregulated -24V DC output, as well as a regulated -14V output, cumulative 500mA max. It is not really suitable as a laboratory power supply, as over current protection is done using a fuse on the secondary transformer side. A pretty neat feature however is the overload indicator, if the unregulated voltage rail drops too much it will light up way before there is a risk of the fuse blowing.

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Gossen T4 80 1 Capacitor Replacement

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I recently got this 80V/1A Gossen (SIEMENS branded) T4-80-1. It was in original condition and some of the capacitors did not look quite so good. Cable grommet The rubber cable grommet started to become oil after all these years, so I cut it out and replaced it with a new one after cleaning the mess up. Inside Look Some picture of the inside, I really like the manually wire wound power resistors.

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