Energy storage cap welding

What is capacitor discharge welding?

Capacitive discharge welding, particularly for large-scale systems, is typically done using film-type capacitors. These capacitors store energy along alternating plates separated by a dielectric film. Charge is stored statically along the lengths of the plates. The basic configuration of the film capacitor is provided in Figure 1.

Can e-caps be used for CD welding?

Use of E-caps for CD welding applications does have some challenges. Most notably, E-caps have limits to usable voltages before electrolyte break-down. Current maximum voltages for large capacity E-caps is on the order of 800 V. In addition, E-caps are relatively intolerant to voltage reversals.

What is capacitive discharge or CD welding?

Capacitive discharge or CD welding is a variant of resistance welding(1,2). The process differs from the conventional variants largely in the type of power supply used. Conventional systems provide some variant of alternating current to a transformer arrangement.

Can electrolytic capacitors be used in large-scale CD welding applications?

In this study, the suitability of electrolytic capacitor arrangements for use in large-scale CD welding applications was investigated. Baseline for the study was a set-up using a 1280-μF main capacitor. The application was a mild steel weld nut with three projections attached to a similar material substrate.

How does CD welding work?

With CD welding, the main energy is stored in a capacitor arrangement. In application, that energy is discharged through a transformer creating again low voltage – high current power for welding. CD welding does differ from conventional resistance welding in a number of ways(1).

Do electrolytic capacitors yield identical weld performance results?

The results presented here indicate that electrolytic capacitors, configured to provide similar charge voltage and energy storage, can yield identical weld performance results. Process, mechanical strength, and metallographic results are all identical for the two capacitor arrangements.