hi I’m a new member in this forum and I’m building my own power monitoring device using Emonlib.h, 1x Arduino Mega 2560, SCT019, and ZMPT101B with 3 phase electricity star configuration. In the experimental test that I have tried, why the real power value and power factor when I try inductive load (such as 1 phase motor) and resistive load (such as incandescent lamp) it is not accurate. The phase shift must be calibrated repeatedly, with a value where when I set the resistive load at -1.5 and when the inductive load is set at a value around 3.9. Is there an additional program or is my calibration calculation wrong?
Welcome, @Christophorus_Elgi_N, to the OEM forum.
No, you are wrong. The phase shift in emonLib affects the phase angle between the voltage and the current that emonLib reads, and shows it as an error in the power factor. An inductive load affects the phase angle between the voltage and the current, and emonLib sees that and shows it as a power factor but with an error.
OK so far?
The difference is, the power factor from the inductive load is part error, part real and genuine, what you see as the power factor from the resistive load is wrong: by definition, a resistive load has a power factor of exactly 1.0.
So you adjust the phase correction with your resistive load to remove the error and show a power factor of 1.0 (or as close as you can) and then you leave it alone. When you connect the inductive load, what you read really is the power factor of the inductive load. And if it reads about 0.7 or less, this is probably right for a small motor, or maybe 0.3 for the coil of a relay or contactor.
Okay thank you for your advice sir.