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An introduction to Current Transformers

Many of us do not know the purpose of current transformer. A current transformer is kind of electrical instrument that is produced particularly to provide a flow of current in the secondary circuit that is properly perpendicular to the amount of current flowing in its primary circuit. It actually measures alternating current flowing by way of a conductor. As it is used to measure current, a current transformer is normally classified as a kind of instrument transformer. It could also measure the voltage drop across any known resistor. This could be applied for a low current application but is often impractical for high current applications. The resistor consumes more power (decreasing efficiency) unless the resistor is extremely low in value, in such case there might be very little voltage the measure. The resistor can also be very large. The resistor's heat might affect the resistor value, so reducing accuracy of its measurement.

A current transformer could accurately calculate the alternating current and put out a reasonable voltage that is proportional to the current, but it is without as much heat and size that an appropriate resistor may require. The current transformer could perform its function with extremely little insertion loss into the conductor current is been calculated. A current transformer as well offers voltage isolation among the conductor and the measuring circuitry. Proper function of a current transformer wants use of a load resistor. And load resistor is normally referred as to a "burden resistor".

The most excellent core structure for a current transformer in way of electrical performance is a toroidal coil. Many toroidal current transformers normally have only one winding. This winding is generally a "high turns" winding that functions as the secondary winding. In application, the toroidal current transformer is fallen over an end of a high current wire or buss bar that further conducts the primary current.

Split core current transformers are especially planned so that they could be gathered around a buss bar without cutting off the buss bar. "C"- cores and "U" core structures are normally used for split-core current transformers as they are comparatively simple to take apart and put back together across the buss bar. Traditionally, this has not been realistic for toroidal coils, but there are presently some supple toroids that allow the "split-core" feature of installing it around a buss bar. They have restricted application. Some printed circuit board applications would use bobbin wound current transformers with two or more windings.