Experimental Study of HBC Fuses with Aluminum Fuse Element at Minimum Rated Breaking Current, Maximum Rated Breaking Current and Transfer Current of Fuse-Switch Combination

The article presents an experimental study of high breaking capacity fuses with aluminum fusible element with and without a eutectic point, at minimum rated breaking current, preceded by experiments at maximum rated breaking current. The paper shows that in the construction with aluminum fusible element, the fuse has no problem breaking the maximum rated breaking current, but real difficulties appears when it comes to the minimum rated breaking current. The experiments were made on a homogeneous series 6-20 A, with a focus on the 36 kV, 25 kA, 16 A fuse. The fuses suffered multiple construction changes and tests with and without a eutectic point. After several tests was found an acceptable constructive solution was, but the obtained value for the minimum rated breaking current is not a commercially attractive value. It was also tested the capacity of the fuse to transfer the breaking duty to a load break switch.