On Wednesday 28 December 2016 23:49:00 Danny Miller wrote: > I can tell you this with confidence- the reliable, quality brand is > "Meanwell". > > They all look pretty much the same, they're not. > > http://www.ebay.com/itm/Mean-Well-MW-5V-3A-15W-AC-DC-Switching-Power-S >upply-NES-15-5-/351760561983?hash=item51e690373f:g:NbMAAOSwepJXYhR4 > > http://www.ebay.com/itm/GENUINE-MEAN-WELL-POWER-SUPPLY-ADAPTER-ES18A05 >-050-5V-3A-15W-max-100240v-/112229820233?hash=item1a216b2749:g:nssAAOSw >A3dYGUnC > > Meanwell isn't even notably more expensive. > > Danny > > On 12/28/2016 4:42 PM, John Thornton wrote: > > Hi Gene, > > > > Want to test one of my 5v 3a regulated power supplies? > > > > JT > > > > On 12/28/2016 4:33 PM, Gene Heskett wrote: > >> Greetings everybody; > >> > >> Now I am asking a question that I should know the answer to. > >> > >> It looks like, from the evidence so far, that this 5v 4a little > >> switchmode psu should be sent to the fcc and let them ban it from > >> ever coming off the boat or airplane on US soil. > >> > >> Its "static" ground terminal is common to the case, and I have now > >> grounded it by way of a couple flat braided ground straps about > >> 5/16" inch wide, back to the ground bolt in the bottom of the box. > >> Ditto the static ground on the z motors 60 volt psu. House static > >> coming in is now also bolted at that stud. The scope probes ground > >> lead is on that stud, the clipon probe is clipped to one of the > >> ioconnectors ground pins. > >> > >> That point is bouncing around 2.5v p-p with the switching activity > >> in that psu. That bolt s/b common to the lathes bed casting thru > >> the bolts that mount it on a post bolted to the chip pan, which is > >> braced by an angle iron bolted to this post, with the end of the > >> angle, about 8" away, bolted solidly to the bed casting at the > >> other end. > >> > >> I purposely did not connect anything in the at667 encoder wireup, > >> to the frame anyplace. If I could find a good, real dirt ground > >> for the scope probe, I take bets that the whole latch is bouncing > >> at least 25 volts p-p to that real ground. > >> > >> The only way I can see ATM, is to install some "longitudinal" > >> filters, therefore chokeing that noise back into the psu instead of > >> giving it something to work against in the form of a solid > >> connection to the powerline. I can source such a filter from Dave > >> at the tv station as I know he has a pile of failed monitor pcb's, > >> all of which will have good filters we can excavate. > >> > >> Or should I take the chance that the next one I buy on fleabay, > >> would be quiet? Your call. > >> > >> > >> Cheers, Gene Heskett > > This noise maker is in fact a Meanwell I bought from MPJA. But if I still had a good am radio, I could set up a df loop, I'd bet I could find it every 17 kilohertz to at least 75 megahertz! This has ringing components that exceed the vertical bandwidth of my Hitachi V-1065, rated at 100 mhz, but I have actually used it to look at the driver stage output of a 50 kw tv transmitter on channel 8, which is nominally 180 megahertz.
Scrounging around in my junk box, I found a computer psu that I had "borrowed" a power hexfet out of several years ago, and its line input filter was actually on a separate PCB, so it was quite easily clipped out of the circuit. Looks like a 5 pole push pull Chebychev design. I'd have to make a box for it if I use it, but I can put it in circuit for S&G's in about 15 minutes tomorrow as a test. Noise coming back in on the supposedly grounded and shielded cable to the encoder in the lathe, about 8 feed of cable, is 1.95 v p-p on the 7i90 input connectors ground pin. With all that running on 5.09 volts, and feeding a 3.3v circuit on the pi, there simply is no way in hell thats not going to putz with the data integrity. And its doing a great job of that. So we'll see what this filter does to it tomorrow. In the meantime, I'll have JT send me one of his for "testing". USPS can probably have it in my mailbox by Monday from his place. > > -------------------------------------------------------------------- > >---------- Check out the vibrant tech community on one of the world's > > most engaging tech sites, SlashDot.org! http://sdm.link/slashdot > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > ---------------------------------------------------------------------- >-------- Check out the vibrant tech community on one of the world's > most engaging tech sites, SlashDot.org! http://sdm.link/slashdot > _______________________________________________ > 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) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
