Defination of Split-Core CT Current Transformers

Just like the typical current transformer, the split-core current transformer measures alternating current flowing through a conductor.
The distinguishing feature of the split core current transformers is that their design permits them to be assembled around a buss barwithout disconnecting the buss bar. The typical current transformer is usually a toroidal coil, which is slipped over the end of a buss bar, hence requires disconnecting the buss bar.

"C" - cores and "U" core structures are commonly used for split-core current transformers because they are relatively easy to take apart and put back together around the buss bar. Some sort of bracketry or band clamps and holds the assembled pieces of the split-core current transformer together. Historically, this has not been as practical ( but is possible ) for toroidal coils. The bracketry is more complicated. Typically, the coil(s) must be sector wound on the toroid before cutting the core in half, whereas the “U?and “C?core structure of the typical split-core current transformer permit use of bobbin wound coils which can be wound independently of the core. There are now some flexible toroids, which permit the “split-core?feature of installing it around a buss bar.

Split-core current transformers for lower frequency applications ( power frequencies ) typically use grain oriented silicon steel or nickel alloys for the core material. There are some more exotic materials available. The material is cut into strips and then wound on an arbor ( mandrel ) to form a core. The core is then cut in half. These are known as “tape-wound?cores because their construction resembles a roll of tape.