Causes of dc energy storage capacitor failure

What can cause a capacitor to fail prematurely?

Repeated applications of high voltage transients may cause a premature failure. Dielectric breakdown may occur as a result of misapplication or high voltage transients (surges). The capacitor may survive many repeated applications of high voltage transients; however, this may cause a premature failure.

What causes compromised connections in capacitors?

High ESR, low or no capacitance typically result from compromised connections, the cause of which varies depending on the capacitor type. Mechanical damage, harsher environment along with some production defects are the dominant factors for Inductors failures. Masashi Ikeda, Sr. Technical Manager, Material R&D

What type of capacitor is most likely to fail?

Mica and tantalum capacitors are more likely to fail in the early period of use (early failure), while aluminum electrolytic capacitors are more likely to experience wear-out failure due to aging use. In the case of film capacitors, when a local short circuit failure occurs, the shorted area may temporarily self-heal.

What happens if a capacitor fails?

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'.

What causes a hermetically sealed capacitor to fail?

Several factors can lead to the failure of a hermetically sealed capacitor. Movement within the case can cause shorts or opens, and fatigue in the leads or mounting brackets can also result in catastrophic failure. The operating altitude also plays a role in determining the capacitor's voltage rating.

What happens if a film capacitor fails?

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.