That's entirely possible as well, but I figured the injector would have shut down fast enough to prevent that as well. On Apr 24, 2015 1:41 PM, "Ken Hohhof" <af...@kwisp.com> wrote:
> Is it possible he has some surge protectors in the path and those are > what got blown, not the radios? > > *From:* Forrest Christian (List Account) <li...@packetflux.com> > *Sent:* Friday, April 24, 2015 2:36 PM > *To:* af <af@afmug.com> > *Subject:* Re: [AFMUG] Packet flux question > > > I actually do a very fast, software defined, overcurrent shutdown in the > product of interest here. It's been a while since I worked on that code > but it will shut down a short circuit in a few ms or so. > > The software defined part allows some flexibility in the shutdown which is > important in that I also have to not shut down for inrush currents. The > algorithm is such that if the overcurrent is small it shuts it down slower > than a, large one. Roughly, it trips once a certain amount of excessive > energy is seen. I'm guessing in this case the amount of energy we let > through is more than the windings on the magnetics can handle. If I have > time I'll grab a set of magnetics and see if I can characterize this. > > I'm also surprised that the 100 series radios died as well as they should > appear as a dead short to the injector and have no magnetics on those pins > to blow up. > On Apr 24, 2015 8:58 AM, "Chuck McCown" <ch...@wbmfg.com> wrote: > >> Forrest, please forgive me for even thinking this thought... but I >> wonder how much current it takes to blow a phy transformer and how hard it >> would be to have an over current shutdown. I have done over current >> shutdowns before and have used those over current passive devices that self >> heal. Polyfuse I think is the name.... >> >> Like you need more ideas... >> >> *From:* Craig House <cr...@totalhighspeed.net> >> *Sent:* Friday, April 24, 2015 5:26 AM >> *To:* af@afmug.com >> *Subject:* Re: [AFMUG] Packet flux question >> >> Thanks Forrest. It was a mix of 450 and 100 series. They all appear to >> have been damaged. The only thing I get an Ethernet link light on is a >> bh50 radio >> >> Sent from my iPhone >> >> On Apr 24, 2015, at 05:06, Forrest Christian (List Account) < >> li...@packetflux.com> wrote: >> >> Hmm.. I love (not) autocorrect on android... port, not portal... But >> now I'm on a real computer and have a chance to re-read the original >> message, and think a bit... I think I need to change my final answer. >> >> If these were 100 series radios I'd say "that seems rather odd that this >> would cause a failure". BUT... I'm assuming these are 450 radios. >> >> With the 450, there's a ethernet transformer on each pair. To DC, this >> is effectively a short. Or since these are made with very thin wire you >> could probably more accurately call it a 'fuse'. So if you take a pair >> and put say the + lead of a 24V power source on one wire in the pair, and >> the return (-) on the other pair, you'd find that the wire in the >> transformer would melt, and would probably do so very quickly. This is >> *exactly* the wiring that the 320/430 radios used. In addition, there is >> every possibility that the current being drawn before melting is smaller >> than the amount of current needed by a real 320 or 430 radio on power on. >> So, when this got plugged in, there's a good chance that you melted the >> ethernet transformers. >> >> The good news is if this is what has happened, it should be a fairly easy >> fix by almost any electronic repair shop which knows how to rework surface >> mount boards - just remove the magnetics and replace them. >> >> Unless of course there was another cause. >> >> -forrest >> >> >> On Thu, Apr 23, 2015 at 9:58 PM, Forrest Christian (List Account) < >> li...@packetflux.com> wrote: >> >>> Due to the odd wiring the radios probably shorted out the overcurrent >>> protection in the injectors, turning off the portal and I'd not be >>> surprised if the radios are just fine. Especially if they were never >>> plugged into an already on injector. >>> So we accidentally put sync injectors on to a din rail today that were >>> for the 320/430 radios. Oops >>> >>> Both of the injectors were powered by a 24 V 10 amp power supply >>> All of the radios that were plugged into those injectors no longer >>> appear to boot up which wouldn't surprise me if there had been a 56 V power >>> supply or 48 V power supply powering them. However since they were powered >>> by a 24 V power supply how could that have damaged the radios? >>> >>> Sent from my iPhone >>> >> >> >> >> -- >> *Forrest Christian* *CEO**, PacketFlux Technologies, Inc.* >> Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602 >> forre...@imach.com | http://www.packetflux.com >> <http://www.linkedin.com/in/fwchristian> >> <http://facebook.com/packetflux> <http://twitter.com/@packetflux> >> >>
