Saturday, February 14, 2009

It's why the lights flicker

One of the features of the software that came with my new UPS* is the ability to produce graphs of the input voltage. As you can see the voltage does vary quite a bit; not enough for the UPS to transfer the computer onto battery backup but certainly enough to flicker the lights.


*Uninterruptible Power Supply - basically a battery backup to keep my computer going during our frequent power cuts.

1 comment:

Pete said...

That's a fairly sizeable variation there Keith! I think we're used to something a little more stable than that. That said, your supply would be perfectly legal in the UK.

You may well be aware of an absolute masterstroke of bureaucracy in the catchily titled "Electricity Supply (Amendment) (No. 2) Regulations 1994" statutory instrument. This was a new regulation to harmonise the UK power supply of 240V with the Continental Europe standard of 220V. The result was to split the difference and regulate the new power at 230V. The masterstroke was allowing the voltage variance to be a whopping ten percent above or six percent below.

The result of course was that nobody changed a damn thing, and the UK stayed on 240V and Europe on 220V and both were compliant with the harmonisation directive.

Sir Humphrey would be proud.