Electricity Meter flashing light

A kw hr is a unit of energy and has no actual time dependent part.

It the number of joules used by a 1kw load in an hour, or a 2kw load in

You will get 1000 flashes for each kw hr of energy used whatever time it takes.

You can determine the actual watts by timing the flashes if you want or count them to see how much energy you have used.

If it's not time dependent then why is there the hr mark in there?

If it flashes and nobody is there to see it, has it really flashed at all? Brian

It is an amount of energy. It doesn't matter whether you use 0.5kW for 2 hours or 2kW for 0.5 hours, it is equivalent to taking 1kW for 1 hour. Yes time is used in the calculation, but the final result is not time dependent , it is simply an amount, which could be spread over any length of time. To see this, simply convert kWh into Joules ... again a simple amount of energy, but no mention of time.

SteveW

to get rid of any time dependency.

To confuse people?

Because there is already time built into the watt and the two cancel out

It does a good job of it.

A kW/hr is a unit of volume.

What time is it?

Is it?

I would say it was M . L^2 . T^-4 ?

Otherwise your post went over my head!

Its 3,600,000 joules of energy.

The poster said kW/hr which is a rate of change of power. However, I doubt that is what he meant.

That depends on whether energy itself has a time dependent part.

My own feeling is that it does, as indeed this article and other articles would have us believe:

kw are a measure of power, and hours a measure of time, so you have in effect power multiplied by time.

Power is the rate of flow of energy - i.e. energy divided by time, so with kw h you are getting:

energy

------ x time time

Two times cancel out, and leave you a measure of energy with no rate of use component.

It does not matter

dimensionally watts= energy/time

again dimensionally, watt.hrs = (energy/time).time = energy

You say 1000 flashes in an hour = 1 kilowatt flowing every hour. 1000 flashes actually means 1000 watt-hours have been consumed. If it takes 2 hours or 30 minutes or any other period for 1000 flashes, 1000 watt-hours have still been consumed, but not at the same wattage.

The unit is watt-hours, not watts per hour which doesn't make sense.

It does. Its the ramp rate of a power source or sink.

I.e. in the UK when the sun rises on a sunny summers day the power output of all thjose solar panels rises at a peak of about 3GW per hour..