- OT: mechanical spindle+wire/cord properties - 5 Updates
- I'll never use an oscilloscope again - 3 Updates
- digelec 824 manual? - 1 Update
| N_Cook <diverse@tcp.co.uk>: Aug 07 09:32PM +0100 Firstly what is it called , friction drive of a few turns around a spindle and kept under tension? the traditional radio tuner frequency change mechanism, linking dial and pointer to a spindle. Then how to evaluate slip/not-slip for various drum surfaces,diameters, wire/cord types and tension |
| Mike Coon <gravity@mjcoon.plus.com>: Aug 07 11:07PM +0100 In article <omaihl$753$1@dont-email.me>, diverse@tcp.co.uk says... > change mechanism, linking dial and pointer to a spindle. > Then how to evaluate slip/not-slip for various drum surfaces,diameters, > wire/cord types and tension Well, it's the principle of a yacht winch. We put up to four turns of the jib sheet round the winch to get a really good pull, though with modern "self-tailing" winches we aren't so aware of the tailing tension. The texture of the barrel surface is another factor; different manufacturers use different patterns but I don't know if they are patented. When I built my own valve oscilloscope decades ago I used a similar mechanism to move a flexible scale past a small aperture in the front panel, but I don't remember how I designed that aspect! Mike. |
| Clifford Heath <no.spam@please.net>: Aug 08 11:20AM +1000 On 08/08/17 06:32, N_Cook wrote: > change mechanism, linking dial and pointer to a spindle. > Then how to evaluate slip/not-slip for various drum surfaces,diameters, > wire/cord types and tension Capstan. The hold force is an exponential function of the total angle wound around the capstan, so if it slips, add another turn. <https://en.wikipedia.org/wiki/Capstan_equation> |
| N_Cook <diverse@tcp.co.uk>: Aug 08 08:01AM +0100 On 08/08/2017 02:20, Clifford Heath wrote: > Capstan. The hold force is an exponential function of the total > angle wound around the capstan, so if it slips, add another turn. > <https://en.wikipedia.org/wiki/Capstan_equation> Google was getting me nowhere near Eytelwein's formula or even mention of capstan, thanks. A historical investigation into how an extreme tide height got erroneously into the records via a type of tide gauge made by Cary Porter 100 years ago. Looks like a design flaw relating to this effect. http://eprints.nottingham.ac.uk/33859/1/resubmitted_pdf%20%28Green%20Version%29.pdf shows one of those recorders. It looks as though the wire to the pen carrier traverse goes around a 1.5 inch drum, behind the brass flange , on same axis as the 120 tooth cog. The 2 weight carriers ,under the table, providing the friction . Rather than the wire fixed to the drum, relying on this capstan friction. So in an extreme tide, one of the endstops, on the wire at the top, jams against the small end pulley, friction on the 1.5 inch capstan is loovercome and the wire slips on the drum and bang goes the calibration. A permanent offset until recalibrated |
| Phil Allison <pallison49@gmail.com>: Aug 08 01:30AM -0700 Nutcase_Kook wrote: ----------------------- > Firstly what is it called, friction drive ...... ** This device, once common in radio tuners is a friction drive. https://upload.wikimedia.org/wikipedia/commons/a/af/Planetary_reduction_drive.JPG I have one in my bench audio oscillator driving a large, dual gang WW pot. .... Phil |
| makolber@yahoo.com: Aug 07 01:37PM -0700 It does sometimes happen that you can see the video picture on an oscope waveform. It can happen with a simple picture like the station call letters when the scene lighting is such that the left of the picture is brighter then the right , and you have the scope set to the V rate. or something like that, it is eerie. mark |
| bruce2bowser@gmail.com: Aug 07 09:07PM -0700 On May 6, 2017 at 1:23 PM, Trevor Wilson wrote in sci.electronics.repair: > **Mmmm. Diana Rigg. The subject of more than one schoolboy dream. Then > there was that beautiful Lotus Elan. Mmmm. > Still, a young Joanne Lumley was delectable in The New Avengers... When was that movie at the box office? |
| John Robertson <spam@flippers.com>: Aug 07 10:59PM -0700 > too? > Nah, I think I'll just take the scope to the garage and shut off all the > breakers in the garage..... There was a short story that took care of the problem of machines not being connected to power - they simply started up themselves. I recall driverless buses crushing pedestrians and tanks, etc running around killing everyone they could. What was the name of the story! 1950s I'm pretty sure... John |
| heymattay@gmail.com: Aug 07 03:07PM -0700 Hey. Did you happen to find the Digelec 828 manual? |
| You received this digest because you're subscribed to updates for this group. You can change your settings on the group membership page. To unsubscribe from this group and stop receiving emails from it send an email to sci.electronics.repair+unsubscribe@googlegroups.com. |
No Response to "Digest for sci.electronics.repair@googlegroups.com - 9 updates in 3 topics"
Post a Comment