"Perfect" OU tests?

[Enigma516]

very interesting video thank you for sharing. Now for someone like me I am not sure how best to test the Joules conversion power output in a controlled repeatable measurable way. Do you have any suggestions?

[TinselKoala]

very interesting video thank you for sharing. Now for someone like me I am not sure how best to test the Joules conversion power output in a controlled repeatable measurable way. Do you have any suggestions?

Not specifically, without knowing the details of the device under test.

In general, using properly filtered input measurements, multiplied and integrated over time, will give correct energy input data. Output data in general can also be measured this way. But since I have no idea what test kit you have or the specifics of the DUT, I can't be more specific about testing, either.

Integrating an instantaneous power waveform is the mathematical equivalent of determining the area enclosed by the waveform (since the total waveform is a geometric representation of power x time) and will result in an answer in Joules passing your measurement point during the time interval. Back before DSOs with math, people even did things like tracing the waveform off the scope onto tracing paper, then cutting it out and weighing the paper on an analytical balance -- the weight of the paper is proportional to the area of the waveform cutout.

[Madebymonkeys]

I beg to disagree with Enigma's early posts above, a little bit, because what is important is not power in/out..... but rather _energy_ in and out.

I an electrical system, power out / power in would be considered a good measure of efficiency.
Power = Joules per second
Energy = Joules

You could argue that power is the correct measurement.

http://en.wikipedia.org/wiki/Power_(physics)

It's easy to fool oneself by looking only at power measurements, and there are many examples of this happening right now.

I disagree - power is a very reasonable thing to measure, always has been.d

I have SSTCs that have inputs of less than a kW and produce "outputs" of many kW if measured naively. My "tinselkoil 2.0" delivers 7-10 amps at 30 kV or higher, yet is powered by ordinary American mains power, 120V at 7 amps. How can this be? It is because peak power is not the same thing as average power, reactive power is not the same as real power, and proper measurement -- integration of the instantaneous output power over a suitable time period, to yield energy flow data -- is elusive and apparently misunderstood by many experimenters.

I do agree, it's not an easy thing to measure at all.
If the system isn't chaotic then there will be some repetition in the input and output waveforms - sampling voltage vs current in the time domain over a long period (and at high bandwidth), and using the point data and math to calculate the power, could be a way forward with standard oscilloscope HW and a spreadsheet?

If power is the only measurement available, be sure to measure real power by using it in Joule heating measurements, like JLN's coffeepot tests of the induction hob "ou" claims. This kind of measurement, properly done, is a rough quick and dirty physical integration which does eventually yield energy flow data.

As an idea, the heating could be performed with something like a power resistor, say a bifilar wire wound type. This would be as near as damnit purely resistive and could have its terminations easily made watertight. This could then be used as the heating element for the tests you describe above by immersing it in a flask of water.

That said, power quality measurements are still important especially if you are to hook the system up to the grid.

[dtard]

And what is grid. Grid and O.U and really I don't want to have to mess with battery's. Think i'm gona have to figure this out on my own

[Madebymonkeys]

And what is grid. Grid and O.U and really I don't want to have to mess with battery's. Think i'm gona have to figure this out on my own

Huh?