Risks: A damaged casing can expose the internal components of the capacitor to the environment, leading to rapid deterioration and failure. Appearance: Rust or corrosion on the capacitor’s terminals or casing indicates aging or exposure to harsh environmental conditions.
Screw terminal type aluminum electrolytic capacitors are designed for upright mounting with the terminals on top. Reverse mounting with the terminals on the bottom is not possible. This may shorten the life of the capacitor or cause dangerous damage such as liquid leakage or capacitor rupture.
However, excessive electrical, mechanical, or operating environment stresses or design flaws during the manufacture or use of electronic equipment cloud give rise to capacitor failure, smoke, ignition, or other problems. This paper describes failure modes and failure mechanisms with a focus on Al-Ecap, MF-cap, and MLCC used in power electronics.
In the case of film capacitors, when a local short circuit failure occurs, the shorted area may temporarily self-heal. An open mode failure in a capacitor can have undesirable effects on electronic equipment and components on the circuit.
A capacitor can be mechanically destroyed or may malfunction if it is not designed, manufactured, or installed to meet the vibration, shock or acceleration requirement within a particular application. Movement of the capacitor within the case can cause low I.R., shorts or opens.
When current repeatedly flows into a defective part due to overvoltage or dielectric degradation, the capacitor continues to self-heal and loses capacitance. Generally, a capacitor is considered to have failed when its capacitance drops by 3% or more compared to its initial value. The probability that a failure will occur is called 'failure rate'.