Fluke 434 - Manual (Page 58)

Fluke 433/434
Users Manual
13-4
unbalance should not exceed 10 %. In case of too high unbalance, use other measuring
modes to further analyze the power system.
Each phase voltage or current can be split-up into three components: positive sequence,
negative sequence, and zero sequence.
The positive sequence component is the normal component such as present in balanced 3-
phase systems. The negative sequence component results from unbalanced phase-to-
phase currents and voltages. This component for instance causes a ‘braking’ effect in 3-
phase motors: this will result in overheating and life reduction.
Zero sequence components may appear in an unbalanced load in 4 wire power systems
and represent the current in the N (Neutral) wire. Unbalance exceeding 2 % is considered
as too high.