On Sunday, 3 April 2022 07:50:27 EDT Leonardo Marsaglia wrote: > > What are you searching for? You don't really need the optical > > isolator if the VFD and computer grounds are tied together. If you > > do want isolation then almost any optical isolator will work Even > > those "C" shape sensors will do the job, The resistor and the > > capacitor are essential but their values are not critical as long as > > the product of the R and C adds up to about the same. > > I just caught what you were asking lol, I'm a little burned out these > days. I was searching for Andy's suggestion to see if there was > something here but it's complicated. Electronic component distributors > here are not that big like the ones in the US . So they don't have the > variety you have there. Also they are not that well optimized for > online selling like for example Digikey, so searching for a component > is really a pain in the ass sometimes. In fact, many times in the past > when my brother and I were experimenting with induction heaters, it > was a lot easier and practical to purchase everything from Digikey and > ship it here, the shipping usually took 3 or 4 days. The obvious > problem is when you have to purchase 5 USD on an item and the shipping > costs like 80 USD. > > El dom, 3 abr 2022 a las 6:10, gene heskett (<[email protected]>) > > escribió: > > On Saturday, 2 April 2022 23:51:58 EDT Chris Albertson wrote: > > > What are you searching for? You don't really need the optical > > > isolator if the VFD and computer grounds are tied together. If > > > you > > > do want isolation then almost any optical isolator will work Even > > > those "C" shape sensors will do the job,
This is true but there is a caveat: That ground must be tied to the SAME bolt ALL other grounds are tied to, and NOPLACE else. That way if the system suffers a lightning strike, that effectively causes the ground to bounce 150,000 volts for that couple microseconds, it all bounces in unison, without any great parts blowing surges being seen by the circuitry. This room with all its electronics I'll offer as an example, when I made this little middle bedroom into a computer room way back in dialup days, as I was moving into my then new wifes house, I used every outlet the room had. And blew a modem everytime the can across the street got hit. I went on a rampage because this kit house was wired by carpenters 45 years ago without the proper crimping tools, who had the idea that static ground and neutral were interchangeable. So I traced out, verified, fixed any common connections I found and soldered every connection between the old pushmatic service and that one wall plug. Then installed a big surge absorber with accessory sockets for cable and phone lines. Its plugged into that one wall socket, and everything else in the room is plugged into that. I have not lost anything to lightning strikes since, although I did get dinged once while typeing on a wired keyboard, surprising me at the time that the keyboard survived but it did. Sorta like the ding you get from walking across the rug and grabbing a doorknob. Wireless mice and keyboards are the rule now. That rework was done 28 years ago, so I think I must have done something right. > > And quite likely they can also do the voltage boost to a 10 volt > > swing > > needed at the output, and 20x faster than the typical 4 pin opto. I'd > > put them in the dark with a heat shrink sleeve though. Stateing the obvious: Cover both prongs with one BIG hunk of heat shrink though, the optical path between them must be clear. Heat shrink with a glue liner recommended. Pinch the top shut before the glue hardens. The idea is to keep any ambient light out. > > > The resistor and the > > > capacitor are essential but their values are not critical as long > > > as > > > the product of the R and C adds up to about the same. > > > > I'm not convinced the filter would be needed, the vfd will generally > > have its own filter. [...] Cheers, Gene Heskett. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
