A major problem in high-voltage designs, particularly of the automotive variety at 500V and higher, is surface arcing or arc-over discharge across multi-layer ceramic capacitor (MLCC) terminals. In addition to the expensive physical damage that results from an arc over, there is the matter of users’ safety, i.e., it’s usually not desirable, except for the occasionally obnoxious in-law or two, to arc-weld passengers to one’s vehicle. Addressing this phenomena, capacitor specialist, guru, and manufacturer KEMET unveiled its ArcShield Technology for high-voltage commercial and automotive applications this week.
According to KEMET’s Senior Vice President, Chief Technology Officer and Chief Scientist Dr. Phil Lessner, "ArcShield devices inhibit surface arc-over discharge, thereby preventing damage to the capacitor and surrounding components on a printed circuit board." Notably, Bill Sloka, KEMET’s Specialty Product Manager, further enlightens by saying the technology features a unique, robust internal shield electrode system that suppresses arcover while increasing available capacitance.
Conquering the arcover situation, the components were initially developed to solve flex crack issues, the primary plague of MLCCs. KEMET’s Flexible Termination technology allegedly thwarts board stress to the body of the MLCC, impeding flex cracks that invite short and open circuits.
Essentially high-voltage components ArcShield MLCCs are available in a number of variations including high-voltage automotive grade. As per the company, the components target mission and safety-critical applications including power supplies, LCD fluorescent backlight ballasts, HID lighting, telecom equipment, industrial and medical equipment/control, LAN/WAN interfaces, analog and digital modems, and, of course, automotive.
On the personal side, I’m having a unique arcing problem in the front end of a monaural, 50W audio tube amp running in Class A mode. Maybe KEMET has a cap for me. For your own edification, more info on ArcShield Technology components can be found at http://www.kemet.com/highvoltage.