LEM introduces high-performance split-core current transformers for energy-efficiency and active power monitoring

The new transformers feature an absolute accuracy better than 1 percent at the nominal current and even better for lower primary currents. The ferrite material provides an excellent linearity of better than 0.1 percent even at very low levels, and the transformers have a particularly low phase shift between measured voltage and current of 1.5˚ ±1˚. The hard and dense core allows very small air gaps to be achieved and is virtually insensitive to ageing and temperature changes, in contrast to laminated FeSi or FeNi materials.

Two ranges of primary current measurement are available: 50A and 100A. The dimensions of the TT 50-SD are only 36.5 x 43 x 31.5 mm with an 8 mm diameter sensing aperture for non-contact measurement. The TT 100-SD measures 44.5 x 51 x 36.5 mm with a 16 mm diameter sensing aperture.

With a 3000:1 ratio, the TT 50-SD and TT 100-SD have low output currents (respectively below 16.66 mA or 33.33 mA). This, together with the internal output-protection circuit, guarantees safe and easy installation without the need to shut down operation since there is no risk of producing a high voltage surge when the transformers are opened, unlike 1A or 5A output products.

Being small, safe, self-powered and split-core, the TT current transformers are very easy to install and put into operation. They are ideal for distributed measurement systems and can be retro-fitted into existing installations and non-interruptible equipment. Principal applications will be in the field of energy sub-metering and cost allocation, dynamic consumption and peak analysis, energy waste or defective equipment detection and power quality control.

As with all other LEM industrial products, the TT transformers benefit from high-quality standards and are backed by a five-year warranty.