Beckhoff KL3403 Series Documentation page 17

In this context, further parameters of the mains system and its consumers are significant:
• apparent power S
• reactive power Q
• power factor cos φ
The KL3403 determines the following values:
• active power P
• effective voltage U
• effective current I
From these values, the required parameters can be calculated:
• apparent power:
• reactive power:
• Power factor:
Sign for power measurement
The sign of the active power P and of the power factor cos φ provide about information the direction of the
energy flow. A positive sign indicates the motor mode, a negative sign indicates generator mode.
In addition, the sign of the reactive power Q indicates the direction of the phase shift between current and
voltage. The diagram Four-quadrant representation of active/reactive power in motor and generator mode
illustrates this. In motor mode (quadrant I & IV) a positive reactive power indicates an inductive load, a
negative reactive power indicates a capacitive load. In generator mode (quadrant II & III), an inductive acting
generator is indicated by a positive reactive power, a capacitive acting generator by a negative reactive
power.
KL3403 Version: 3.1.0
Product overview
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