How it is calculated
Hours may be left blank, and then you get power only. Cos φ for a heater is close to 1. For a motor it is often lower.
P = U × I × cos φ
Where the numbers come from
- Voltage — unit in the field: V
- Current — unit in the field: A
- Cos φ
- Hours — unit in the field: h
Example
220 V and 5 A at cos φ = 1 give 1100 W. Over 2 hours that is 2,2 kWh.
Questions
Three phases?
The formula is for a single phase. For three balanced phases, multiply by √3 and use the line values only if U and I were measured that way. Otherwise calculate one phase and multiply by three.
Are the kilowatts already on the label?
Then multiply hours by kilowatts yourself. This screen is the one that turns current into watts.
Do blank hours mean zero?
No, the energy is simply not shown.