Michael Gilligan | 24/08/2021 18:04:49 |
![]() 23121 forum posts 1360 photos | Fun isn’t it … the more we think about this, to more obscure its purpose becomes ! MichaelG. |
Jon Lawes | 24/08/2021 22:34:06 |
![]() 1078 forum posts | Just scraping the barrel for clues, Martin says it was in the bottom of a crate of tooling. Where did it come from? Do we have any hints there? |
Martin King 2 | 25/08/2021 05:57:38 |
![]() 1129 forum posts 1 photos | Hi Jon, no help I am afraid, it was discovered under the flap of a cardboard crate about to go in the bin! just a box of mixed tools and stuff. Martin |
SillyOldDuffer | 25/08/2021 09:53:39 |
10668 forum posts 2415 photos | Posted by Graham Meek on 24/08/2021 16:37:16: ... If this tool was for testing spark strength then the "Go" condition would pass a fairly weak spark. Whereas the "Not Go" would be failing one hell of a spark. ...In which case maybe it detects over-voltage? I wonder if it was used on a process that incidently but usefully generated static electricity, such as unrolling paper for a high-speed printer. A mild static charge would be useful for attracting ink, but too much static would collect dirt, consume excessive ink, and blur the image. Might explain why one contact is square. It's rested on an edge while the peephole side is tilted to touch a hot test point. If it sparks the machine is generating too much charge, and a resistor would be adjusted to bleed off electrons. The amount of charge generated by friction depends much on the weather, so the machine might have needed frequent adjustment. Electronics made this easy to automate after about 1975, so the gauge may have had a short working life. Is 'Micrograph' print-trade jargon? Small writing, specks of ink, rather than the 'magnified picture of a small object' definition we're familiar with. Dave
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Graham Meek | 25/08/2021 13:17:58 |
714 forum posts 414 photos | I did think that the test was for a weak spark, rather than a really powerful one. While working at Rank-Xerox, their copiers had a power supply to deal with attracting ink onto the paper. With special electrodes with numerous spikes on to distribute this to the paper. High speed printers which I have also worked on, (made in Germany and used mainly in the car industry, paper speed was around a metre/s, if my memory serves me correct), used a similar set-up and what was called in house a Corotron assembly. Maybe as Dave suggests, this tool pre-dates the Xerox as regards a printing process. On a separate theme, I did wonder if it had anything to with Marconi or Tesla, and the early spark generated communication. Not necessarily for the spark used, but for setting any air based capacitors in the circuit. Regards Gray, |
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