Is like high-pressure sodium lamp, light bulb is marked 400W, but the actual use of current is greater than the current formula according to U.I=W, that is to say, high pressure sodium lamp power factor is relatively low, seems to be about 0.5! I don't know. It's been a long time since I graduated. How do I calculate the power and current with the power factor?! Which master can provide the formula and the specific algorithm, as well as the lamp is 400W high-pressure sodium lamp, the actual input power is large, how much current? Thank you！
When the number of electric voltage less than 220 V or 380V you'd better use a multimeter to measure the actual voltage in different time after a mean value of this error will be smaller error but also the error is inevitable
Power factor I do not remember, the current is 1.8A, which is in the case of voltage 220V current, 380V current is 1.05263, specifically according to your location in different time periods of different voltage to calculate the actual working current I=W/U
Rated current I=P/U=400/220=1.82A. The actual current is I=P/ (U * cos phi) =0.4/ (0.22*0.5) =3.64A. P is rated power, unit: kw. U rated voltage 0.22kv. Cos phi is power factor. The actual input power is P=U * I=220 * 3.64=800w.
