1 réponse
Attention !!
Watt (hence kW as well) is the unit of active power (i.e., consumed by resistances or converted into mechanical power)
It is the power properly speaking in the physical sense
P = UIcos(phi)
VA (hence kVA as well) is the unit of apparent power
S = UI
There is also reactive power (consumed by inductors and capacitors) whose unit is VAR
(volt-amp reactive)
denoted Q
Q = UI sin(phi)
The relationship between the 3 powers
S² = P² + Q²
In the special case where there are no inductors and capacitors Q = 0
therefore S = P (equality in value)
Note: in direct current there is only active power which is simply called power.
Watt (hence kW as well) is the unit of active power (i.e., consumed by resistances or converted into mechanical power)
It is the power properly speaking in the physical sense
P = UIcos(phi)
VA (hence kVA as well) is the unit of apparent power
S = UI
There is also reactive power (consumed by inductors and capacitors) whose unit is VAR
(volt-amp reactive)
denoted Q
Q = UI sin(phi)
The relationship between the 3 powers
S² = P² + Q²
In the special case where there are no inductors and capacitors Q = 0
therefore S = P (equality in value)
Note: in direct current there is only active power which is simply called power.