High current AC harmonic filter capacitors expands capabilities

Cornell Dubilier now offers 85A RMS ratings and many other improvements to its PC series of AC harmonic filter capacitors. The series improvements incorporate UL recognised construction and an internal pressure interrupter system that has passed strict UL testing to guarantee fail-open performance under high current fault conditions. The higher current ratings increase the capacitor’s capability to handle the high levels of harmonic content found in inverter AC input and output filtering applications.

The series is networked with inductors to filter out unwanted harmonics in both single-phase and three-phase AC power systems. As a two-terminal capacitor device, multiple PC series capacitors may be attached in delta or wye configurations to deliver the reactive power and harmonic tuning required to filter out the unwanted frequencies. The presence of many harmonics puts further stress on capacitors in the form of self-heating. The series is created with robust terminations and low ESR, to reduce heating. The service life objective of the series is 60,000 hours when run at full rated voltage and a case hot spot of 70C.

The series is provided with capacitance ratings ranging from 20µF to 125µF at voltage ratings from 300VAC to 700VAC. Case diameters vary from 63.5mm to up to 116mm. Custom capacitance and voltage ratings, sizes and performance characteristics are also offered. Specific application conditions, particularly harmonic content profiles, are required to correctly size the capacitors for peak performance.