[Explanation of the cause of capacitor failure] The pressure valve does not operate, and steam is ejected from the grounding surface.

Review the requirements for the pressure valve to operate and the regulations for ensuring safety, and secure the necessary space!

In this case, snap-in aluminum electrolytic capacitors were used in the power supply equipment, and to make the equipment thinner, the heat sink was closely positioned against the top of the capacitor. During a test for abnormal conditions in the equipment, an intentional overvoltage was applied to the capacitor, which caused the pressure valve located on the top of the capacitor to fail to operate and resulted in overheating. Subsequently, vapor from the electrolyte burst out from the grounding surface of the capacitor. The cause was that the capacitor shorted due to the overvoltage, leading to current flow and overheating. The heat vaporized the electrolyte, causing pressure inside the capacitor to rise, and since the pressure valve did not operate, gas from the electrolyte burst out from the sealing part of the capacitor on the grounding surface, shorting the wiring pattern on the substrate and causing a spark that resulted in smoke. [Countermeasures] - Review the requirements for the pressure valve to operate and the regulations for ensuring safety, and secure the necessary space. - If sufficient space cannot be secured, a type with a pressure valve on the side of the capacitor is recommended. *For more details, please refer to the PDF document or feel free to contact us.

Capacitor