# Calculate phase shift from desired power factor

I'm learning how to calibrate energy measurement device, and acting upon colleagues instructions I'm getting worse results in each iteration. I'd like to check with someone here if instructions are correct.

Calibration requires to set such load to have power factor 0.5. According to instruction, I need voltage at 240 angle and current set at 300 angle. However, this results in worse result. Setting 240 angle of voltage and 180 angle of current provides expected results. Which phase shift between voltage and current here is correct?

I'm aware my question is probably faulty in many ways, however this is best way I'm able to express with my current knowledge.

## 1 Answer

If the voltage has a phase angle of 240º and the current is either leading or lagging by 60º (300º or 180º absolute) then the power factor will be 0.5 on both occasions.

PF = cosine of angle between voltage and current.

It's a little worrying that you are not seeing the same power factor at 300º and 180º