Electrolytic Capacitor 1

Gideon Analytical Laboratories received three electrolytic capacitors that were failing in the field. A capacitor stores electrical energy. They have two terminals separated by some type of insulating material, known as a dielectric. Usually, these dialectics are metal plates and the dielectric is made of materials like ceramics, mylar, or glass. Electrolytic capacitors are a type of capacitor that uses an electrolyte as one of its plates to achieve a larger capacitance per unit volume. The storage potential of a capacitor is known as capacitance and is measured in farads, and since most capacitors are generally small, micro farads are the most often used measurement of capacitance. All of these capacitors measured a short across the respective terminals. The goal was to determine the cause of failure.

Failure analysis was conducted. To begin with, a possible knurling problem that might produce burrs when the IIR was inserted and aluminum compressed was investigate. No aluminum from the can was pressed into the leads nor was any contamination or metal objects discovered in the IIR. The Kraft paper was inspected and electrically tested. Kraft paper is paper or paperboard (cardboard) produced from chemical pulp produced in the Kraft process. It is paper with high elasticity and high tear resistance that serves as a dialectic. Upon inspection, aluminum bits were found embedded in the Kraft paper. But this was not the major problem.

It was apparent that the stitching had worked its way through the Kraft paper and was causing a short on the adjacent plate. Copper deposits were also noticed near the lead perimeter. The foil was severely scored, but the anode foil was worse than the cathode foil. In summary, one of two things caused this failure: aluminum contamination or insufficient insulation between the plates. In any case, copper is a contaminate in this arena. This is a manufacturing issue.

At Gideon Analytical Laboratories, we strive to help companies in the electronic field diagnose the causes of their failures. We have the expertise, the experience, and the equipment to get the job done right and in a timely manner. Have your problems solved by the problem solvers of the electronics industry. Call Gideon Analytical Laboratories today.

Kraft paper unrolled, contents revealed

Kraft paper unrolled, contents revealed

Pitted Anode foil

Pitted Anode foil

Pitted foil of the Capacitor

Pitted foil of the Capacitor

Lead arcing

Lead arcing

Kraft paper wound

Kraft paper wound

Kraft paper inspection

Kraft paper inspection

Evidence of the lead arcing

Evidence of the lead arcing