Fuse

The fuse with a length of approx. 25 mm, with nickel-plated caps, glass tube and with a fuse wire attached with soft solder on the inside, should be bonded to connecting wires on both sides. These tinned connecting wires with a diameter of 0.5 mm require a lot of welding energy.

Both connections must be welded on with a cycle time of about 0.7 seconds after assembly.

If the fuse should be heated up beyond 300°C during the welding process, the soft solder fixing the fuse wire on the inside of the cap will melt. A temperature of about 1'500°C is necessary, however, in order to melt on the nickel layer.

These requirement may be met only with very fast welding cycles. Our tests have shown that a welding time of 0.4 milliseconds ensurs that the solder on the inside will remain intact and will at the same time be sufficient in order to melt on the nickel layer. This short welding time requires an extremely steep current rise and is practically only feasible with capacitor discharge technology.