On Tuesday 15 December 2015 13:20:52 Jerry Scharf wrote: > Gene, > > I don't think these optos have anything to do with SSRs. These are not > designed to pass power, just an open collector output logic circuit. > The AC voltage is the rating of the breakdown voltage. > > jerry > I may not have made myself clear, I was refering to the isolation voltage, not the SSR's withstand. Looking it the very limited specs on MPJ's web page, the SSR's 480 was specified, but there was another 480 which I took to be the isolation voltage.
Heck I get a fair amount of my exercise these days jumping to conclusions. ;-) I may have to take a good flashlight up on the old hill & see what I can find for a bleeder in the old transmitter spares, best I can find in my scrap pile is a pair of 6k, 10 watters. They'll work, and if left live in-circuit, will only do a bit less than 4 watts each powered up in parallel. But I'd much druther have something that will heat itself at least 100 watts for a few seconds as a bleeder. Something that will render it tool safe in the time it takes me to pull the cover screws and the cover. 3 minutes maybe. Today, I gave up pulling that lid panel flat, so I changed how my clamps are pulling on it, then poured about a 3rd of a 16oz bottle of Dasani water on it & wiped it wet all over with a paper towel, then pulled it about 2x as hard. If that doesn't flatten it out, $50 worth of mahogany will go in the burn pile. Although I haven't taken a steam iron to it yet. . . Maybe thats next, tomorrow. But I'll use it dry and iron a wet, white bath towel dry on it. Fewer water stains I think. I am never buying even a toothpick from the wood peddler again. > On Tue, Dec 15, 2015 at 10:09 AM, Gene Heskett <ghesk...@wdtv.com> wrote: > > On Tuesday 15 December 2015 10:33:55 John Kasunich wrote: > > > On Mon, Dec 14, 2015, at 10:51 PM, Gene Heskett wrote: > > > > On Monday 14 December 2015 19:11:49 Jerry Scharf wrote: > > > > > Hi, > > > > > > > > > > Just did a super quick google search and came up with a > > > > > fairchild optocoupler hcpl2530 that will do 1Mbps. ~1.80 USD > > > > > quantity 1. Isolation to 480v and good common mode rejection. > > > > > There are a number of devices in similar and better speeds. > > > > > > > > I was wondering if faster stuff was filtering down into the > > > > afordable category in the last decade, But only 480 volt > > > > isolation? that would have to be mesa isolated on the same > > > > substrate, edge emitting diodes facing edge sensitive > > > > transistors. I think it depends on the environment if thats > > > > enough isolation. With noise from higher speed/volatge stepper > > > > drivers nearby, I'd be a tad nervous. > > > > > > "Only" 480V? > > > > > > Jerry wasn't saying "these devices fail at 481V". They are UL > > > approved for use as isolation between 480V power systems and > > > low-voltage control. The actual isolation rating is far higher > > > than that. The hipot test spec is 3750V RMS for 1 minute. > > > > Thats much closer to what I was hopeing for John, thanks. Most it > > seems are rate in the 4 to 5 thousand range. So I do not expect any > > surprises. > > > > > Optos are getting pretty good these days. At work I use the > > > Renesas PS9924, an extra-wide body one that can meet safety regs > > > at 690V AC, even at high altitudes where thinner air requires > > > larger clearances. Hipot rating is 7500V RMS! Sub-100nS prop > > > delays, easily handle 5MHz data. Cost is still under $10 each, $5 > > > in quantity (a bargain if you need such performance). Datasheet: > > > http://documentation.renesas.com/doc/YOUSYS/document/r08ds0059ej01 > > >00_p s_family.pdf > > > > These things are, I assume, SSR's at heart, meaning they are > > intended for AC service only if ever expected to be turned off? > > > > The ones I have coming are probably older stuff and the SSR portion > > would be slower too. But that, in this circuit, shouldn't be a > > concern. They'll be a few days arriving, so I'll have plenty of time > > to conjure up a safety bleeder. And figure out how to interlock it > > so it cannot be re-enabled until the bleeder has done its thing and > > self disconnected. I have some 3pdt ice cubes and one of those, self > > latching until the cap is down, is likely to find a new home. > > > > > > 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) > > Some mill pix are at: > > Genes Web page <http://geneslinuxbox.net:6309/gene/GO704-pix> > > > > > > -------------------------------------------------------------------- > >---------- _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users 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) Some mill pix are at: Genes Web page <http://geneslinuxbox.net:6309/gene/GO704-pix> ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
