A miniature current transformer which consists of a busbar and a coil is easy to assemble in an electricity meter or other devices. We can make such kind of component by integrated the ring-type current transformer with a U shape metal rod or plate. Here we introduce each part of a typical current transformer with a busbar.

Structure of Current Transformer with Busbar

1. metal shield or metal case
2. busbar
3. plastic casing for primary
4. plastic casing male for core
5. plastic casing female for core

The picture shows the main parts of a current transformer before filling the epoxy resin. The coil, consists of a soft magnetic core and a few hundred or thousand turns of enamel wires, is not shown in the picture, as they are protected by the plastic casing male & female. The busbar serves as primary winding which is one turn. Sometimes, we put a heat-shrink sleeve or silicon tube on the busbar which is made of copper or brass. As this is the metal shield type current transformer, plastic casing for isolating the primary busbar is required. We can make sure the withstanding voltage between the primary and secondary winding more than 3000V. For the plastic case current transformer, the structure is simpler, as no metal case is required.

Then, how to put all these separated parts together and make a component as a whole? Please refer to the article below, which introduced the whole process of our current transformer.

Mini Current Transformer: Production Process