TechTalk: 2019 DistribuTECH
Booth #10342 at DistribuTech (Feb 5-7 in New Orleans). Exciting new Orion and Bitronics products and features!
January 23, 2019
This non-invasive approach provides for quicker installation with no disruption of service. Many split core or clamp-on options though, come with the compromise of reduced accuracy, reliability and overall performance. Bitronics solves these problems with our nickel-core, individually calibrated, Split-Core CTs made in the USA. Each has a 20A (for 50 Series) or 100A (for M871) primary rating, a 1000:1 turns ratio, and is calibrated to each specific meter and phase, and so are not interchangeable. Mounting brackets bolt to any flat surface with two screws.
Split Core CTs are rated for indoor use and intended for lines having 5A nominal full scale, which are energized to no more than 600V (that is, on the low-side of an existing substation CT). It is not intended to be the main CT on an energized load-carrying conductor including LV applications (residential/light-industrial, less than 600V) where load-carrying conductors generally supply significantly more than 5A. Neither is it appropriate for use on substation CTs that have a 1A nominal full scale.
Accuracy
Each Split Core CT is calibrated to linearize the response of the transformer, resulting in 0.2S class accuracy (IEC 62053- 22 & 23). Heat- treated high-permeability (“superm”) nickel core material produces superior low-end response, phase angle response, and repeatability characteristics compared to ferrite core material competitors. In addition, nickel core material is not brittle, whereas the tension exerted on a ferrite core CT by its secondary windings is often sufficient to chip or fracture the core, affecting its magnetic characteristics.
Range
Split Core CTs operate at 5A nominal full scale, but they can operate up to a maximum of 10A (50 Series) or 100A (M871) with rated accuracy.
Durability
The spring-tensioned two bolt gate in the Split Core CT is more durable than the hinge-and-snap type gates used by some competitors, and reduces variation in the magnetic characteristics resulting from repeated opening and closing of the gate. The surfaces where the gate closes the core are lapped for a near-perfect mating surface.
Safety
The CTs use Zener diodes to protect against changes in the magnetic characteristics of the core that could otherwise result from operating with the secondary leads open.
Mounting
Plastic mounting brackets are available for most mounting situations. A twenty-five foot length wire is provided, but by specifying a current-rated output (as opposed to the more common voltage-rated output), the impact of adding a reasonable extension (up to 40 feet total) in the wire length from the split-core CT to the meter is minimal.
