Reactive power - Reactive Generator research from GotoLuc - discussion thread

[hartiberlin]

"Multiply the current by 10 as CSR is 0.1 Ohm." - gotoluc
We should then have 3.2A.

Can you again confirm this Luc ?

I thought your scope had already calculated the 10 times factor in via your scope settings ??


Well, if it is really 3.2 Amps then this means also
as then you are shuttling also back and forth about 800 Watts from and to the Grid !
No wonder the transfomer gets so hot then via its losses !

Then these 20 Watts of Real active output power are only a small fraction of the big
240 Volts x 3.2 amps =768 VA (Watts) of
apparent power being drawn.

So this is only a 2.6 % ratio . Could this still be then some kind of measurement error ?

[poynt99]

poynt99,
The current sensing resistor is using ohm's law and an oscilloscope to detect the voltage drop.  This method is probably the most accurate method possible.  Luc's data is indeed valid.

"Multiply the current by 10 as CSR is 0.1 Ohm." - gotoluc
We should then have 3.2A.

Cheers,
matt

There are some problems:

1) Luc is using a voltage probe. The scope was set to scale according to a current probe (what scaling did he use?). Even if the scaling was set to 100mV/A, is this valid? Would you bet your house that it is? Does the fact that the probe is maybe a x10 probe throw the amplitude out by a magnitude?

2) The resistor being used to measure current, is it non-inductive wound?

3) In a series RLC circuit, does the current lag the voltage, or vice versa? Or is it either? What determines this?

4) How is it that the screen amplitudes of both traces ended up the same? Coincidence?

[hartiberlin]

There are at least two problems:

1) Luc is using a voltage probe. The scope was set to scale according to a current probe (what scaling did he use?). Even if the scaling was set to 100mV/A, is this valid? Would you bet your house that it is? Does the fact that the probe is maybe a x10 probe throw the amplitude out by a magnitude?

2) The resistor being used to measure current, is it non-inductive wound?

3) In a series RLC circuit, does the current lag the voltage, or vice versa? Or is it either? What determines this?

No, this should not matter,
only if the shunt is a bit inductive, but then it shifts just the phase a bit more or less,
so we could still have some more Real Active power than the scope shows...

Luc just confirmed that it is really 3.2 Amps:

"Hi Stefan,

the current is 320ma x 10 so 3.2 Amps is running through the circuit."


Okay, but as the shunt is only 0.1 Ohms, its inductance impedance is
probably too low to have an effect on the phase shifting in this setup.
But maybe the scope head capacity calibration was not done ?
Would this be a problem in this case ??

[codeboundfuture]

1) Luc is using a voltage probe. The scope was set to scale according to a current probe (what scaling did he use?). Even if the scaling was set to 100mV/A, is this valid? Would you bet your house that it is? Does the fact that the probe is maybe a x10 probe throw the amplitude out by a magnitude?

Tektronix manual -
"Current probes provide a voltage signal proportional to the current. You need to
set the oscilloscope to match the scale of your current probe. The default scale is
10 A/V."
The voltage probe is detecting the voltage drop induced by the current through the resistor and giving a proportional voltage signal to the oscilloscope.  I'm sure you still want a confirmation from Luc about his settings but he has already stated that it's 10x what is displayed.

2) The resistor being used to measure current, is it non-inductive wound?

You would be hard pressed to get a phase shift from a .1 ohm resistor at 60hz, the inductance necessary would require a much larger resistor.

3) In a series RLC circuit, does the current lag the voltage, or vice versa? Or is it either? What determines this?

http://www.electronics-tutorials.ws/accircuits/series-resonance.html  The section "Phase Angle of a Series Resonant Circuit"

4) How is it that the screen amplitudes of both traces ended up the same? Coincidence?

It's a setting on the scope to change it to an arbitrary value, it was made to match on purpose, probably for simplification of viewing.  You can see the setting at the bottom left of the scope screen.

[minnie]

Hi
   this thing seems to be doing what is claimed. Could anyone please tell me how it could
be used in a practical way?
                           John