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Domanda n.1 (ask on 20/11/2015) : How should I interpret the Vunb parameter present with the Fresnel diagram on my Qualistar+?
data risposta 20/11/2015 :
The Vunb parameter can be used to qualify the level of unbalance on a three-phase network.
To calculate the unbalance Vunb, the instrument takes into account:
- The unbalance due to the values of the three phases
- The pahse shift between the three phases
- Correct connection of the three phases
- Formula:
Where Vunb is the unblance, Vi is the negative phase sequence and Vd is the positive phase sequence of the three-phase network.
If Vunb = 100%, it means that:
- One phase is disconnected
- Two or more phases are inverted
- Several of the Qualistar+ voltage inputs are on the same phase
