On Tue, 18 Jan 2005, Christopher L. Wade wrote: > Scott Stingel wrote: > > The reason for an asterisk system to be able to work from -48v is really > > only if the end-user customer requires it as part of a spec. - I would > > think only a minority of sites would require this though. These days, > > most equipment rooms I've been in can supply lots of backed-up AC. > > Pardon me, my 'ee' experience was a long time ago, but isn't it "easier" > to provide clean DC than it is to provide clean AC?
Redundancy is another issue - it is easier to provide redundant feeds if there can be no phase misalignment. > Basically, if you run all of your power through AC-DC converters then > through battery banks (basically capacitors) finally going out to your > equipment, any and all problems introduced from your AC source is > effectively filtered out. This is similar to what really expensive UPS > units do, except they also convert back to AC as a final step. They are not that much more expensive anymore. The problem is that with a double conversion ups you have slightly lower efficieny, leading to more power use and more waste heat. They typically run at 90-95% efficiency. Peter _______________________________________________ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
