On 11/25/2014 11:20 AM, John Andersen wrote:
A lot of telecom and industrial network equipment runs on -48V DC,
provided by batteries. Also, many server sites run the computers on high voltage DC, to eliminate the AC-DC and DC-AC conversions. You could probably modify a typical computer power supply for that, but you'd need a string of about a dozen 12V batteries to run it. Computer switching power supplies rectify the incoming AC and use the DC to run a power oscillator at a high frequency that's then passed through a transformer to be rectified and regulated at the desired voltage. In North America, that DC would be in the vicinity of 150V. That's the most tortured description of a power supply I've ever heard.
Transformers do not rectify nor are they used with DC.
I guess I was too brief with a brief description. I was just trying to point out the stages the power passes through. AC in > rectify > power oscillator > transformer > rectify and regulate
DC output.
With high voltage DC, the first rectify can be omitted and, if UPS is used, the DC > AC conversion, in the UPS, is also eliminated. Eliminating those two stages improves the overall efficiency, which is a major consideration in a large server site. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org