Find Corona

If you suspect that corona is an issue in your system, here's one simple way to detect corona. The CoronaFinder, manufactured by Syntronics, is a real-time viewing system that looks for the ultraviolet glow of corona. If you look at their website at http://www.syntronics.net/CoronaFinder.htm, you'll see a couple of dramatic photos. One shows wires using normal light, and the second shows the same view as seen through the CoronaFinder.

Comparison: Ceramic and Film High Voltage Capacitors

Both ceramic and film capacitors are widely used in high voltage applications. Ceramic high voltage capacitors have the following advantages, as compared to film:

• Lower equivalent series inductance (ESL) and equivalent series resistance (ESR)
• Smaller size for the same value (capacitance & voltage)
• Better temperature coefficient available, as well as a choice of temperature coefficient characteristics

Disadvantages of ceramic capacitors include:

• Higher voltage coefficient, resulting in substantially lower capacitance as the applied voltage is increased. (This characteristic is often overlooked, and its effects are often more severe than you would think.)
• Lower maximum available capacitance rating
• Lower maximum available voltage rating
• Susceptibility to piezoelectric effects
• Typically smaller lead-to-lead distance