Re: [OT] Electricity Bill

["Qriz B" <QrizB@xxxxxxx>]

--- In ukha_d@xxxxxxx, "Marcus Warrington" <marcusw@m...>
wrote:
> On the subject of electricity usage I did a quick test the other
> night. I checked the meter reading and I left my main PC
> (Athlon1.4 + 7000rpm fan, 2 IDE 7200rpm discs, 19" Belinea
Monitor)
> on all night, then checked the meter, then left the PC off all
> night and rechecked. Figures were 11.5 units used when PC was on
> (10:30pm - 10am) compared to only 5 units used with PC off
> (10:30pm - 8:30am).

I hope I'm not teaching you to suck eggs here, but you can check
consumption a lot faster than that if your electricity meter has one
of those spinning discs in it.

The discs rotate at a speed related to your rate of electricity
consumption. Somewhere on the meter display will be marked how many
revolutions per kilowatt-hour - I've seen meters with 400 revs per
kWh and 266 revs per kWh, but there are probably others.

Turn on the piece of kit you want to measure, then use a stopwatch to
time how long each revolution of the disc takes. Then turn off the
piece of kit, and repeat the measurement.

You can then convert these measurements into rates of power
consumption with some simple maths.

For example:
With your Mk III SuperDoobrey turned on each revolution of the disc
takes twelve seconds. With it turned off, each revolution takes
eighteen seconds. Your meter says 400 revs per kWh.

There are 3600 seconds in an hour. With the Mk III SuperDoobrey on,
twelve seconds per revolution is (3600/12=) 300 revolutions per hour.
With 400 revs per kWh, your power consumption is (200/400=) 0.75
kWh / h (ie 0.75 kW, or 750 watts).


With the Mk III SuperDoobrey off, eighteen seconds per revolution is
(3600/18=) 200 revolutions per hour. With 400 revs per kWh, your
power consumption is (200/400=) 0.5 kWh / h (ie 0.5 kW, or 500 watts).

The MkIII SuperDoobrey is therefore consuming 250 watts.


HTH.



QrizB.