Low Zero Sequence and Phase Shifting Autotransformers
A 3-phase, low zero sequence impedance autotransformer, which when connected near to and in parallel with the harmonic generating non-linear loads (usually connected at the distribution panel), provides an alternate path for 3rd, 9th, & 15th current harmonics (triplens) which the loads create. Patented Field Adjustable Impedance (FAI) feature allows for adjustment of NCE™ zero sequence impedance to field conditions.
Reduces neutral current and neutral-to-ground voltage as well as both current and voltage triplen harmonic distortion.
A patented phase shifting autotransformer with a low zero sequence impedance at its output. When connected in series on a 3-phase, 4-wire service to non-linear loads, it provides an alternate path for the triplen harmonics. The CNCE™ also phase shifts 5th and 7th current harmonics by 180º so that they cancel with 5th and 7th harmonics from other loads on the distribution system. Optional FAI feature allows for removal of triplens from the CNCE™ input side as well as secondary.
Reduces neutral current, and neutral-to-ground voltage, as well as both current and voltage harmonic distortion at 3rd, 5th, 7th, & 9th harmonics.
3-phase, 3-wire autotransformers with 30°, 15° or 20° phase shift between input and output. They are connected in series with the supply to variable frequency drives, UPS systems, and other 3-phase rectifier loads.
By phase shifting against other similar loads, they reduce 5th and 7th or 11th and 13th harmonic currents at point of common coupling which, in turn, reduces voltage distortion as well.