Today in this post we’ll look inside of old Vettiner 1000pF capacitance standard artifact. It is rated to 0.1% nominal tolerance and rated for working voltages up to 500 V. Standard is built in hermetic sealed aluminum canister with BNC 2TP configuration. Port between electrical ports is a valve for inner volume evacuation/gas fill.

Vettiner is a french high voltage equipment manufacturer, mostly focused on high power high voltage instrumentation. The manufacture capacitors with voltage rating up to 1.2 Megavolts. But today we’ll look at baby 500V model with nominal capacitance 1000 pF.

Exterior of CA 0.5-1000

High potential terminal has plastic mount to the body to reinforce voltage isolation.

Anodized body is very sturdy and industrial looking :) Unusual looking appendix between electrical ports is gas seal valve used to vacuum inner volume or to pressurize it with inert gas for better stability.

Sadly this capacitor developed a fault which resulted it’s delivery to our hands for a little teardown :)

Internal design and build

Top lid is mounted with hex bolts around the edge.

Seal was removed with faint hissing of air intake to inner volume.

However trying to gently pry the lids did not help and nothing moved. Much more force was applied to break the silicone seals and release the bottom plate.

After applying heat with turbopropane torch top lid was also removed, revealing additional o-ring seal.

Connections at the BNC pins are potted with epoxy for additional mechanical and electrical reinforcements.

Thick support plate electrically insulated with polycarbonate or acrylic washers. Capacitance plates are electrically interleaved to form plates with stable geometry.

There are 24 plates in main stack and one additional plate at the very bottom at increased separation space, perhaps used to fine-tune capacitance value?

Projects like this are born from passion and a desire to share how things work. Education is the foundation of a healthy society - especially important in today's volatile world. xDevs began as a personal project notepad in Kherson, Ukraine back in 2008 and has grown with support of passionate readers just like you. There are no (and never will be) any ads, sponsors or shareholders behind xDevs.com, just a commitment to inspire and help learning. If you are in a position to help others like us, please consider supporting xDevs.com’s home-country Ukraine in its defense of freedom to speak, freedom to live in peace and freedom to choose their way. You can use official site to support Ukraine – United24 or Help99. Every cent counts.