On Mon, 2008-12-01 at 17:43 -0500, James Knott wrote:
Most telephone equipment are fed directly from batteries at 48 volts, so they don't need inverters, nor UPS fast takeover and such things. If computers used the same setup, replacing the 120(230) volts power supply with a 12 or 24 volts DC power supply, some things would be easier.
Most of the telecom gear was supplied from the 48V supplies. Some servers, intended for large installations, can run off high voltage
150V DC. The purpose of this is to reduce the losses in power supplies in UPS & computers, as well as resistance losses in the cables.
In fact, I did see a computer power supply with a 12v dc input some years ago. I thought I would see more of them, but that has not been so. I wonder why :-?
From a technical view point, it wouldn't be difficult to modify a computer power supply to operate from DC, at a voltage that's similar to what that supply creates from AC. In computer power supplies, the incoming AC is rectified to some DC voltage. That DC power is then used to run an inverter that converts it down to the voltages required by the computer. If you supply the appropriate high voltage DC, you can bypass the AC input & rectifiers. Such a supply could be easily designed to run off 12V. You might be able to find some with Google.
When ordering servers from HP, you can specify whether you want AC-power adapters (110 - 230Vac) or 48Vdc-apapters. Only catch is that you have to be carefull that in telco-stuff the plus is grounded, while other equipment (like RF-transmission) use negative-grounding. Unless you are fond of sparks and welding, you're in for a nasty surprice.. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org