DC Immune CT Core
DC Immune CT Core

DC immune current transformers are important components for energy meters and other electrical instruments. Based on the technology of high permeability and high saturation induction soft magnetic material, we can provide DC immune current transformer cores of good linearity. The CT core usually consists of a nanocrystalline ring and an amorphous ring. Thus, the dual core has the advantage of high permeability and high saturation induction.

Each piece of Xianyu toroidal DC immune CT core an iron-based nanocrystalline and amorphous dual core, protected by high-grade plastic case. The proportion of each part is carefully calculated according to experiments and treated by seperated annealing process with or without magnetic field. So, we can take the advantage of each material and make the final dual cores with excellent linearity.

For our nanocrystalline and amorphous core, the curie temperature (Tc) is 570 °C and 400 °C, both are much higher than that of ferrite core. So, our DC immune composite cores have good thermal stability.

We can make customized cores for a variety of DC immune current transformers. The most popular composite cores are used for miniature current transformers with max. current range from 10A to 200A. But we can also provide high current type DC immune CT core for applications under current up to 600A for different kinds of residential meters or energy meters.

Toroidal core, or round core, is the most popular type of soft magnetic cores, as it has the advantage of nearly no leakage magnetic flux. We make the ring core by ultra thin ribbon with high stacking factor, which allow us to provide mini composite core of very compact size.

Our automatic ribbon winding machines make the competitive price possible in large-scale production. For requirements of customized DC immune cores, we can provide samples based on quick prototype technology within a couple of days.

DC Immune Current Transformer Core


  • Toroidal amorphous & nanocrystalline core inside
  • Good linearity over the whole primary current range
  • Max current range from 10A to 600A
  • Direct coil winding available
  • High initial permeability and low losses
  • High saturated induction
  • Stable temperature character, very low temperature drift
  • AL value specified by customers
  • Quick prototype development for customized cores
  • DC immune according to IEC 62053, EN 50470-3
  • Suitable for residential meters of different accuracy class


  • Current transformers
  • Electricity meters
  • Current sensing
  • Circuit protection

Basic Parameters

Structure Toroidal Inner & Outer Dual Core
Usage Current Sensing
Description DC Immune Current Transformer Core
Material A Iron-based Nanocrystalline 1k107
Material B Iron-based Amorphous 1K101
Finish Type Plastic Box / Epoxy Resin Coating
Color White / Black
Weight Approx. 5~200 g
AL Value Specified by Customers
Application 10~600A DC Immune CT
Accept Customized Yes

Magnetic Properties


Saturation induction (Bs)1.2 THardness (Hv)880
Curie temperature (Tc)570 °CResistance ratio (δ)130 µΩ·cm
Crystalline temperature (Tx)500 °CThickness18~28 µm
Initial permeability(µ0)>12×104Density (ρ)7.2 g/cm3
Saturation magnetostriction (λs)2.0×10-6Stacking factor≥0.8


Saturation induction (Bs)1.56 THardness (Hv)960
Curie temperature (Tc)400 °CResistance ratio (δ)130 µΩ·cm
Crystalline temperature (Tx)515 °CCoercivity (Hc)<4 A/m
Saturation magnetostriction (λs)27×10-6Density (ρ)7.18 g/cm3


Dimensions of DC Immune Amorphous & Nanocrystalline Core
dimensions specified by customers
Model ID (mm) OD (mm) HT (mm) Iron cross
section (cm2)
Mean path
length (cm)
Weight (g)
CP14-19-8B 14 19 8 0.15 5.2 10.5
CP14-20-10A 14 20 10 0.23 5.3 11.5
CP16-21-10B 16 21 10 0.19 5.8 13.8
CP16-25-10A 16 25 10 0.34 6.4 21.5
CP17-22-10A 17 22 10 0.19 6.1 12.7
CP17-24-8A 17 24 8 0.21 6.4 12.7
CP19-27-8A 19 27 8 0.24 7.2 15.2
CP19-27-8B 19 27 8 0.24 7.2 16.5
CP19-28-10A 19 28 10 0.34 7.4 21.7
CP20-30-6.5A 20 30 6.5 0.24 7.9 17.9
CP20-30-8A 20 30 8 0.3 7.9 20
CP40-50-20A 40 50 20 0.75 14.1 95
CP47-64-16A 47 64 16 1.02 17.4 140
CP48-60-15A 48 60 15 0.68 17 86
CP50-60-10A 50 60 10 0.38 17.3 69
CP50-60-12A 50 60 12 0.45 17.3 79

The above data are selected from some popular models we produce. Please contact us for detail datasheet. We can also design some special DC immune amorphous & nanocrystalline cores to meet customers’ requirements.

DC Immune CT Core
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