Our J series are isolated from the chassis unless you bond ground to the positive ground on it. That being said, the fuses are on the - side so you would want to take the main outputs to your own distribution panel or bus with the fuses on the + leg if you were going to run it at +48
On Tue, Nov 27, 2018 at 1:13 AM TJ Trout <[email protected]> wrote: > I get it now, the 48v never changes just the ground reference. > > I'm guessing the reason no one uses negative ground loads on a -48 system > is the chassis ground being bonded to the inputs return. > > Could I therically isolate my eltek -48 from any ground and operate it as > a negative ground system? > > Or if the chassis isn't bonded to either can I just avoid grounding the > supply? > > On Mon, Nov 26, 2018, 10:29 PM TJ Trout <[email protected] wrote: > >> Chuck, >> >> Are you sure the eltek's don't have the chassis ground bonded to the >> positive output ? >> >> So I'm assuming the complication here is that if you reverse the wires, >> when you try to power a +48v device, and it's negative input is bonded to >> chassis ground and you have a ground path between the two (like a metal >> rack) or possibly somehow through the AC ground/neutral you cause a direct >> short circuit? >> >> I see mentions of DC-DC converters, but I don't see the point of using a >> 300w RSD converter with a 2000W rectifier shelf? >> >> >> >> On Mon, Nov 26, 2018 at 2:57 PM <[email protected]> wrote: >> >>> It is 48. Period. You choose the reference if you want one. >>> >>> If you tie the + terminal to chassis ground then the – terminal is the >>> hot –48 VDC terminal. >>> >>> If you tie the – terminal to chassis ground then the + terminal is the >>> hot +48 VDC terminal. >>> >>> If you don’t tie either to chassis ground, then you will have to have a >>> common return bar that is on the opposite rail from your fuses and circuit >>> breakers. >>> >>> *From:* TJ Trout >>> *Sent:* Monday, November 26, 2018 3:40 PM >>> *To:* AnimalFarm Microwave Users Group >>> *Subject:* [AFMUG] Eltek Valere J series -48 or +48 >>> >>> I'm looking at the Valere series and I can't seem determine if it's +48 >>> or -48, seems like it's +48 but I thought all the telecom stuff was >>> positive ground. >>> >>> How do you go about powering negative ground loads from a positive >>> ground power source? >>> >>> I'm assuming you can leave out the neutral and isolate the chassis? >>> >>> >>> >>> ------------------------------ >>> -- >>> AF mailing list >>> [email protected] >>> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >>> -- >>> AF mailing list >>> [email protected] >>> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >>> >> -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > -- Carl Peterson *PORT NETWORKS* 401 E Pratt St, Ste 2553 Baltimore, MD 21202 (410) 637-3707
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