ABB A43 User Manual page 85

Measurement Methods
The following illustration shows a vector diagram for resistive, inductive and ca-
Illustration
pacitive loads:
A load that consumes both reactive and active energy can be divided into active
Phase
and reactive components. The angle between the apparent power (U*I) vector and
displacement
the active power component is described as phase displacement angle or power
factor angle.
The following illustration shows a vector diagram for a load with an active and a
Illustration
reactive component:
The type of load can be represented geometrically by for quadrants. In the first
The 4 power
quadrant the load is inductive and active and energy is imported (energy is deliv-
quadrants
ered from the utility to the customer). In the second quadrant the load is capacitive
and active energy is exported and reactive energy is imported. In the third quad-
rant the load is inductive and active and reactive energy is exported. In the last
quadrant the load is capacitive and active energy is imported and reactive
energy exported.
2CMC48001M0201
Revision: C
U
I
Resistive load
Active power = P = U x I x cos  (unit W)
Reactive power = Q = U x I x sin  (unit var)
Apparent power = S = U x I (unit VA)
Reactive power
U
Clockwise rotation
I
Inductive load

85
U
Clockwise rotation
I
Capacitive load
Apparent
power
Active
power
A43/A44
User Manual