Was Thomas Edison Right about DC Power?

Declan McCullagh writes "Everyone knows the alternating vs. direct current wars ended with Thomas Edison and Nikola Tesla. But now DC power is being seriously considered for data centers. DC advocates say that plugging servers into AC power is inefficient, and switching to DC cuts down on waste heat and component failure. The University of Florida has even bought 200 DC servers."

Comments

They were both right...and wrong...

[davmoo]

Tesla and Edison were both right...and wrong. Like many Slashdotters do when debating which operating system is best for any given job, Tesla and Edison wanted to apply one power system to every job. Its like having a toolbox with only a screwdriver in it. Ever try to drive a nail with a screwdriver?

For moving power over long distances, AC is king. But for short distances with most modern electronics, DC would win. The first thing a desktop system or server does with AC is converts it to DC. So if you have a number of machines all in the same room, why not do the conversion in one spot, and eliminate the redundancy in every machine.

Would it benefit the average user with one or two machines? Not at all. But for a major center with many machines in the same room, I can see quite a bit of benefit with going with DC.

Re:Sensationalist, but effectively correct

[Cobralisk]

DC power is easier to deal with for backup redundant systems than AC. Simply put a battery (or 100 - as many as you like) in parallel and you're done. This is how telephony has always worked. Ampacity is your main concern. There are no frequency/phase angle/power factor related issues. DC is simpler than AC. The -48v in common use(actually closer to 52v, but who's counting) is safe to touch with your bare hands (although you can arc weld a screwdriver with it - melted metal==ouch). The major inconvenience is you just can't send it through a transformer. The added bonus is the internal capacitance of the batteries in parallel makes for a very stable power supply with a nice buffer for spikes/brownouts. The market for this equipment is pretty large and mature, since the entire PSTN(including all dsl service) runs on it already, and the big cable companies are migrating this way as well.

Re:Sensationalist, but effectively correct

[Doc Ruby]

Edison wanted to pump DC across longdistance lines, which would have consumed much more than the 10-20% losses in Tesla's AC. A hundred years ago, electronics complexity was so low that a single electric motor's mechanical power was often distributed around an entire factory by pulleys, rather than use multiple motors. Now we've got more complexity on a single square CPU inch than existed in the entire world when Tesla and Edison battled.

I'd love to see how Tesla would have applied his high frequency/voltage engineering to photonics.