Spot welding is an important manufacturing technique for our manganin shunt resistors. We use the manganin 6J13 or 6J12 as the calibration material, because of its low temperature coefficient and good thermal stability. However, the price is expensive, we rarely made the shunts entirely by manganin plate. With the help of spot welding machine, we can joint the manganin with copper lugs, brass terminal blocks, multi strand wires and make complicated shunt resistors, like primary wire manganin shunts, and so on.
Sometimes, we add some filler metal between the two metals being joined and apply them to spot welding and we call the process brazing. A properly made brazed joint (like a welded joint) may be stronger than the copper or manganin plate being joined. Most of our C shape shunts are made by brazing manganin plate with copper lugs or brass blocks, which can be integrated with our current transformers or latching relays.
Of course, we can also joint the sampling wires to the shunts by spot welding, while the tranditional method is soldering which has bad effect to the environment. In the process, in order to fix the wires firmly, the metal clamps may be required.
Beside spot welding, electron beam welding (EBW) is also widely used in our plant, which is introduced as the post below.