Confirming the Delayed Lenz Effect

[gotoluc]

At everyone,

I forgot to mention yesterday that my test using the pure sine wave inverter the Shunt resistor displayed larger peak (larger than grid tests) on the tops of the current peaks. So I reconnected everything to capture the scope shots. Please look them over and post what you think is the cause of this.

I also activated the Math function as user SchubertReijiMaigo had suggested in his post below.

Hello Gotoluc I have DSO 2090, just a tips to measure the power, use the maths function (CannelA*ChannelB) to display power, if you see a curve that have equal pulse above and bottom the zero line you have reactive power, maybe it will be much easier to read.

If this information is correct the math function seem to confirm it is reactive power.

First scope shot is of the current shunt only
Second is with the inverters sine wave input to the circuit
Third is with Math Function added
and Forth is with the probes separated on their own and Math Function

Please let me know what you think

Luc

[wings]

some calculation with mutual inductance effect give less efficiency 444% instead of 489% (please check my calculation)

next
what is the best way to generate variable reactive power from DC reducing energy loss?

[SchubertReijiMaigo]

@ Gotoluc, Thank you for posting that, but can you display MATHVVmean function, because it's hard to see (the curve contain a lot of harmonics (I wonder where it comes ?)

I have noticed if MATHVmean tend to go higher it' mean that the power is active, but if it stay around zero it's reactive (no matter the MATHVrms value)... Sorry for this late information (I'm still in the learning curve in AC oscilloscope measurement), Yesterday just finished to burn up my amplifier with tuned Resonant circuit... 

[protein_man]

Hello Luc, thanks for you're interesting experiments! Any chance you could measure the power feeding the inverter before and after applying the load of the transformer? This will give a good indication of power use after the inverter.

[gyulasun]

...
I forgot to mention yesterday that my test using the pure sine wave inverter the Shunt resistor displayed larger peak (larger than grid tests) on the tops of the current peaks.
....

Hi Luc,

I think the larger peaks on top of the current peaks come from a starting core saturation, either in your test transformer core or the inverter inside output core or just both.  If you wish to test this, you can insert a series resistor higher than the 1 Ohm shunt to decrease the current, even though it is reactive. As Thane calculated it the reactive power in your previous setup from the mains was about 147 VAR (with 1.23A current) and if you allow  only 1A or slightly less current to flow instead, the spikes should get reduced or should disappear from the current peaks.

Something else I noticed is the 24uf Capacitance used to make my Watts meter display Zero when plugged into the Grid would display 3 to 4 Watts when plugged in to the Inverter. By reducing the Capacitance to 15uf it came back to Zero. So maybe the Capacitance is doing some kind of Impedance matching and fools the meter?
   

I think the inverter inside transformer's output coil adds its own inductance to the series LC you terminate it with and this is why you needed to reduce the capacitor to 15uF. The transformer in the inverter simply detuned your original  LC resonance.  This shows nicely that an inverter cannot really substitute the mains very low impedance, unless the inverter is designed for many kW of output power, for this would involve much lower output impedance by default.

Gyula