Reactive power - Reactive Generator research from GotoLuc - discussion thread

[tim123]

Hi, I've been trying to replicate Luc's setup. I have a question:

As far as I can tell, Luc is taking 2 measurements with his probes:
Probe A: Voltage - measured *before* the 'reactive circuit'
Probe B: Current - measured *after* the RC

He then multiplies these 2 values to get 'power'.

My question is this: Is this valid? Can you measure from 2 different parts of the circuit like that - multiply them - and get a meaningful result?

Regards, Tim

[wings]

perhaps already said:

the measures with alternating current require non-inductive resistor.

http://www.digikey.ch/Web%20Export/Supplier%20Content/Ohmite_273/PDF/Ohmite_Current_Sense.pdf?redirected=1

[poynt99]

Hi, I've been trying to replicate Luc's setup. I have a question:

As far as I can tell, Luc is taking 2 measurements with his probes:
Probe A: Voltage - measured *before* the 'reactive circuit'
Probe B: Current - measured *after* the RC

He then multiplies these 2 values to get 'power'.

My question is this: Is this valid? Can you measure from 2 different parts of the circuit like that - multiply them - and get a meaningful result?

Regards, Tim

Tim,

As best I can tell, if I understand Luc's connections, he is measuring power from/to the grid. CH1 is measuring the voltage across the source, and CH2 is measuring the current through the source.

Because of the probe configurations, a negative net power actually means more power is returning to the source/grid. Normally all sources have a negative power, and elements that dissipate have a positive power polarity.

Two things tell me that Luc has a phase inversion in one of his channels:

a) It is impossible to achieve 90 degrees phase difference (i leading v) between those two measurement points without inverting one channel. At least as I understand the circuit.

b) He has a net negative power, when it should be positive with the probe configuration he is using. One channel being inverted would result in both the wave forms he showed, and the net negative power.

[poynt99]

perhaps already said:

the measures with alternating current require non-inductive resistor.

http://www.digikey.ch/Web%20Export/Supplier%20Content/Ohmite_273/PDF/Ohmite_Current_Sense.pdf?redirected=1

Indeed. Inductance in the CSR results in a larger current being measured. The inductance of Luc's CSR is unknown at this point, but should be measured.

[hartiberlin]

Hi, I've been trying to replicate Luc's setup. I have a question:

As far as I can tell, Luc is taking 2 measurements with his probes:
Probe A: Voltage - measured *before* the 'reactive circuit'
Probe B: Current - measured *after* the RC

He then multiplies these 2 values to get 'power'.

My question is this: Is this valid? Can you measure from 2 different parts of the circuit like that - multiply them - and get a meaningful result?

Regards, Tim

Yes, it is valid, as the current can be measured anywhere in the loop.
You only have to have to have the same ground lines for both scope heads at the same point.

If you do it like I have redrawn here, it is okay:

http://www.overunity.com/14013/reactive-generator-research-for-everyone-to-share/dlattach/attach/130509/

You can also leave the Variac out there out of the circuit if you wish.