LIBERTY, S.C. — Cornell Dubilier Inc. has expanded the capabilities of its PC series of AC harmonic filter capacitors, which now offer 85 Ampere RMS ratings and numerous other enhancements, the company said in a press release.

The series improvements include UL recognized construction and an internal pressure interrupter system that has passed the rigors of UL testing to ensure fail-open performance under high current fault conditions. The higher current ratings are reported to improve the capacitor’s ability to handle the high levels of harmonic content encountered in inverter AC input and output filtering applications.

The series is typically networked with inductors to filter out undesirable harmonics in both single-phase and three-phase AC power systems. As two-terminal capacitor devices, multiple PC series capacitors can be connected in delta or wye configurations to achieve the reactive power and harmonic tuning needed to filter out the unwanted frequencies.

The presence of multiple harmonics puts additional stress on capacitors in the form of self-heating. The PC series is designed with robust terminations and low equivalent series resistance (ESR), to minimize heating. The service life objective of the PC series is 60,000 hours when operated at full rated voltage and a case hot spot of 70° C, according to Cornell Dubilier (

The PC series is offered with capacitance ratings ranging from 20 µF to 125 µF at voltage ratings from 300 Vac to 700 Vac. Case diameters vary from 63.5mm up to 116mm. Custom capacitance and voltage ratings, sizes, and performance characteristics are also available. Specific application conditions, especially harmonic content profiles, are needed to properly size the capacitors for peak performance, the company said.

The PC series enhancements add capabilities to Cornell Dubilier’s broad range of AC harmonic filtering options, which include three-phase cylindrical and welded rectangular cases used in large inverter systems. Cornell Dubilier also offers rack-mount systems, designed and fabricated in-house, to allow for easy integration of capacitor banks into the mechanical design of a filter system.

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