Diagram: Measurement of active and apparent power (wattmeter, ammeter and voltmeter)
The wattmeter displays milli-Watt: so here 1880 mW
The red ammeter (230 mA) in series, the yellow voltmeter in parallel on the coil
The product U * I = 20 * 0.23 A = 4.6 "Watt", for only 1.9 Watt displayed!
The product voltage * intensity is the apparent power supplied by the generator in VA!
The Wattmeter displays the power actually converted (here mechanical to paste relay)
The contact requires 1.9 W to stick but the coil absorbs 4.6 VA!
The 'sources': inverters, transformers ... Indicates power in VA Volt * Ampere
A 2 VA transformer would be insufficient! At least 4.6 VA to provide 2 W!
1.9 / 4.6 (P in W / S in VA) = Cosine phi: cos phi = about 0.3 to 0.4 here
EN green my capacitance which displays 33 μF for capacitors in blue disks.
We will connect the 33 μF in parallel on the coil (at the level of the voltmeter) and observe I
Apparent power bore its name badly: the generator supplies it, the wires transport it
I carry out the paralleling in the level of the voltmeter, more practical and identical
The intensity I is divided by 3! 76 mA against 230! S = 0.076 * 20.5 V = 1.5 VA approximately
Now, with inaccuracies, P in Watt = S in VA! The decrease of P is an imprecision
Here P drop, a little before in fact
S in VA = P in Watt! So the cosine, cos phi = 1!
It is now provided that the actually converted hence the name "power factor"
For the cos phi, review video (same editing) with the oscilloscope as needed
The electric efficiency is close to 1 when cos phi = 1 (remains the losses iron, Joule ...)
Now you do not need to oversize the generator, cables and protections by a factor of 3!
S is supplied by the generator, carried by the cables and absorbed by the receiver
With S it produces Q its reagent: magnetic field that can be compensated
It is indispensable, it can not be suppressed: it is compensated. It is he who produces the force
The capacitors will produce the reagent useful to the coil for its magnetic field
Spend everything in kW, Imagine: between a transformer 2 kVA (cos phi 1) and one of 5 kVA ...
The difference in price, mass, space ...
With Pythagoras one can easily find reactive power