Precise and price-convenient measuring of AC current

General purpose AC current measurment, overload and shortcut protection, load drop or shutdown detection and similar application require simple and reliable solution. Current transformers meet all these requirements and they add further bonuses like galvanic isolation, no intervention to a measured circuit and a convenient price.

As we know, one of AC current measurement methods is based on the usage of a current transformer. Alternating magnetic field around a wire lead, which in a continual proportion to a current flowing through a wire, will induce an AC voltage in a measurement transformer. At a suitable construction and a right transformer loading, is the output voltage in a continual proportion to a current in a measured lead. Perhaps the biggest advantage of this method is the fact, that a measuring circuit is galvanically isolated from a measured lead and at the same time, the transformer doesn´t indtroduce any added load neither any influence. If we´d like to go to a detail, the transformer consumes a negligible amount of energy of few tens of mW/10A from a measured lead, which is being lost in the winding and a load of the transformer.

Every current transformer is designed for a certain load, i.e. at a certain load it provides most accurate results. For example for the type AC-1050 it is 100 Ohms. In such a case is valid a transfer ration 1000:1, i.e. to the load flows a 10 mA current at a 10A current in a measured lead. It means, that on a 100 Ohm we will measure a voltage with a value of 1V. Output of a current transformer can be connected to a panel meter, digital voltmeter, oscilloscope or an AD converter input. By using an AD converter, it is also possible to monitor a course of a current and to discover various nonlinearities in a power consumption.