On 01/10/13 09:37, harryagain wrote:
"The Natural Philosopher" wrote in message
...
On 30/09/13 22:49, Andy Burns wrote:
The Natural Philosopher wrote:

Huge wrote:

Andy Burns wrote:

How much power do you think datacentres gobble up?

Tens of megawatts.

I think that's a little on the high side, megawatts, yes.

3-4MW is about right for each of the datacentres we have servers in,
what fraction of those MW are sipped during the peaks of the sine wave?
How many "big" UK datacentres? 40-50 maybe?


Just about ANY electronics tends to have an SMPS strapped on it. And they
are ALL peak clippers.

It's a huge change from the days when the load on the grid was largely
resistive (lighting) and slightly inductive (electric motors).

Peak currents are much higher than the average..the current waveform is
far from sinusoidal. This leads to far higher losses in the resistive
parts of the grid.


Twaddle.


strap a current probe on the mains and plug the probe into an
oscilloscope and the mains into any item of electronics.

just DO it harry.

Or just THINK for a moment how a sine wave and a rectifier can charge up
a capacitor ins a standard single phase pridge rectifier and capacitor
arrangement, such as every power supply that produces DC off the mains
uses, when for the greater part of the cycle the diodes are reverse
biased and cannot conduct any (significant) current at all.


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.