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Composite Core for DC Immune Current Transformers

Date: Dec 22nd, 2022
DC immune current sense transformers are used for sensing the AC currents where DC offsets also exist. The current sense transformers create a voltage when current flows. They are primarily made for sensing AC currents in a circuit so having a DC bias can distort the AC measurement.

DC immune current transformers (CTs) are used in electrical devices, such as electricity meters to measure the current in the AC circuit where DC offset exists. Each piece of DC immune current transformer consists of the amorphous & nancrystalline dual core manufacured by ourselves. As we used high-grade DC immune CT core inside, the final CT have the ability to handle the DC offsets in the circuit. We make the round winding coil by high-grade enamel wire and turns ratio can range from 1:1000 to 1:25000.

The winding coil of CT should be protected by wrapped insulation tape or plastic case fixed by harden epoxy resin. Plastic case current transformers usually have the advantage of cost, as the coil fix (resin pouring) can be handled by automatic machines. Insulation tape wrapped CT are suitable for flexible demands, as no plastic mold is required, but the price may not so cheap as the insulation tape is wrapped manually.

The most common structure of DC immune CT is toroidal or ring type, and the through-hole is used to assemble busbar or primary wires, maybe together with shunt resistors. But we can also make bus type or busbar built-in current transformers, which can be easily fixed or installed in the meter cases by screwing. In some circumstances, the busbar may be replaced by primary wire manganin shunt.

we can provide customzied DC immune current transformer with a wide-range of dimensions for single phase or three phase watt-hour meters. We can make very small CT, or big ones with max. current as high as 600A for industry meters. Due to our quick prototype technology (3-D printing or resin casting), we can provide samples within a couple of days.

DC Immune Current Transformer Features:

A variety of encapsulations, busbar or through-hole type
Amorphous & nanocrystalline dual core inside
High linearity over the whole primary current range
Accuracy up to 0.05 or 0.1 class, low phase shift & amplitude error
Safe galvanic seperation and high dynamic range
Quick prototype development and sampling
Automatic coil winding for large-scale production
Meet the standard JB/T10665
Customized current transformer available


Energy meters, smart meters
Electromechanical meter
Electrical measuring instruments
Electrical protective devices
Current sensing modules
Adjustable speed drives
Variable-frequency drives
Wind power converter
Power supply