Carlos E. R. wrote:
RFI can be blocked with chokes. Some (many?) DC-DC converters have in fact an AC stage, with a transformer, so there is galvanic isolation. Lightning... ufff!. Dunno. Best thing is a good l. rod.
They all have an an AC stage. It's the only way you can use a transformer to efficiently change voltage. However, they tend to operate at several KHz and not power line frequencies.
You know that bad lighning protection is worse that no protection? It atracts rays, which then find no easy route to earth, and use the house and equipment instead. Fire and disasters.
I remember seeing some years ago a PC power supply that replaced the standard PSU, and had internal batteries, working as an UPS when the AC failed. Ie, it was a PSU/UPS unit in one, with one converter stage less, more efficient, which is something to consider when you are not on mains.
There may exist commercial 12DC PSUs for computers, but probably the inverter road is more known/cheaper.
There is a range of -48 V converters used in telephone exchange. They should be very expensive. And it is -48 because earth is the + line (dunno why, historical reasons, I suppose). All equipment designed for telephone exchange must use -48, but sometimes they are forced to use standard AC mains equipment with inverters. I have seen, for instance, Cisco routers fed from -48 directly.
A lot of telecom gear can be used with either + or - grounded or both sides floating. I could be wrong, but I seem to recall positive ground was used to reduce corrosion of the wires. -- Use OpenOffice.org http://www.openoffice.org -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org