Nominal talk battery is -48 VDC. Ringing voltage is something like 85 to 100 VAC 20 Hz superimposed on the -48 VDC, so that would be unpleasant.
I think Chuck is saying he can’t feel 48 volts on his fingers, you certainly would feel it on your tongue, heck people can feel 9 volts on their tongue. Some applications like T1 line repeaters and payphones used 130 VDC, in fact T1 repeaters would use +/- 130 VDC for a differential of 260 VDC and that can kill you like if you are standing in a puddle working on the line. From: AF <[email protected]> On Behalf Of Adam Moffett Sent: Friday, November 23, 2018 11:19 PM To: [email protected] Subject: Re: [AFMUG] 48v Power Supply Switches I stripped a phone line with my teeth once. Felt something sharp and tingling. What voltage was that? On 11/23/2018 10:40 PM, Chuck McCown wrote: I can’t feel 48vdc Sent from my iPhone On Nov 23, 2018, at 6:40 PM, Adam Moffett <[email protected] <mailto:[email protected]> > wrote: We have a ton of those we can sell you at a healthy discount. We have more than we'll ever use. Hit me off list if you want some. One thing to watch out for on that one is that the + and - terminals are prongs sticking out the back of the unit. This is a bit of a departure from norms. Normally a device supplying power has a socket, and a device accepting power has the prongs which go into the socket. It's unusual to have energized metal sticking out the back. Make sure you're using it appropriately and that it's not (for example) screwed to the back of an electronics enclosure where a technician is going to stick their hand in and get bitten by 48v at 20amp. You might notice on other power supplies the wires connect to a terminal that is recessed in plastic or has a plastic snap cover. Oh also, the jumper to select 240v or 120v was set to 240 by default on all of ours. Just something to make sure the installer is aware of. -Adam On 11/23/2018 10:11 AM, Alex Davidson wrote: Hey guys, we are stepping up to some 48v equipment on a tower and in looking into power supply switches. This seemed to be something that would work for us (Mean Well SE-1000-48). Any thoughts or pros and cons that yall have found with this unit. Any units of similarity that might work well in place of this one. Thanks -- AF mailing list [email protected] <mailto:[email protected]> http://af.afmug.com/mailman/listinfo/af_af.afmug.com
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