Plug-in transformers for the measurement of high-voltage electrical currents.
Plug-in transformers are used for measuring electricity. However, if mains voltage is distributed at high levels, this must be done safely. Instrument transformers remove the dangers in the measurement of high-voltage electrical currents by generating proportionally reduced electricity, for example, for energy meters: They scale high-level electrical currents to small, standardised values, which are then made accessible to digital and intelligent measuring devices. Thus, the transformers make it possible to record even very high electrical currents.
Plug-in transformers are some of the most common and affordable types of instrument transformers and are overwhelmingly used in the installation of rails or cables. For this purpose, the corresponding conductors are fed through the opening in the middle. The prerequisite for installation is the interruption of the primary line. For this reason, the plug-in transformers are the preferred type for installation in newly developed systems.
Since the use of instrument transformers involves high voltages, they should be exclusively installed by electricians.
The primary and secondary rated current indicates the current value for which a transformer is suited. The two values of the rated current are usually proportional to each other and are indicated as an unabridged break on the rating plate. 5A (Ampere) is the value of the rated current for which the transformer is rated. Standardised secondary currents are 1A and, preferably, 5A.
5A transformers are the most common, because most of these measuring devices are of a higher accuracy class. On the other hand, 1A transformers are often used for long measuring cables. The deciding factors here are technical and economic in nature.
Do 1A transformers fit better into your measuring system? Our online store also offers high-quality, reliable 1A plug-in transformers.
Due to the various influences on a measuring device, one hundred percent measurement accuracy is unrealistic. For this reason, instrument transformers are categorised into corresponding classes. DIN EN 61869-2 defines the accuracy classes 5; 3; 1; 0.5; 0.5S; 0.2; 0.2S and 0.1 for instrument transformers. The class number indicates how high the percentage difference may be between the measured value and the actual value.
Thus, the following applies: The higher the accuracy class, the higher the fault tolerance of the measured value to the actual value of the measured current.
