The Protective Link

The protective link is a device recently developed for internal mounting in transformer of a wide variety of types and ratings. Its most common application, however, is in distribution transformers where it serves to disconnect the transformer in case of internal fault. Its action in arc extinction depends on a number of factors including a novel arrangement of the lower terminal which allows it to be expelled from the link when heavy currents are interrupted. Although simple and compact, the link is a very efficient arc-quenching device, and has a remarkably high-circuit interrupting capacity combined with high speed of operation. Power arcs of more than 250,000-kva single phase have been interrupted in one-half cycle.