INDUSTRY COMPONENT

Core

Current transformer core is the magnetic component that enables accurate current measurement through electromagnetic induction in electrical systems.

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Component Specifications

Definition
The current transformer core is a specialized magnetic component typically constructed from laminated silicon steel or other high-permeability materials. It serves as the central element in current transformers, providing a closed magnetic path that concentrates the magnetic flux generated by the primary current. This component enables the transformation of high primary currents to proportionally lower, measurable secondary currents while maintaining electrical isolation between circuits. The core's design directly impacts measurement accuracy, linearity, and performance across various load conditions.
Working Principle
The core operates on the principle of electromagnetic induction. When alternating current flows through the primary conductor, it generates a magnetic field that is concentrated and guided by the core material. This magnetic flux induces a proportional voltage in the secondary winding wound around the core, allowing for accurate current measurement while maintaining galvanic isolation between primary and secondary circuits. The core's magnetic properties determine the transformer's accuracy class, saturation characteristics, and frequency response.
Materials
High-permeability silicon steel (typically 0.23-0.35mm laminations), nickel-iron alloys (for high-precision applications), amorphous metals (for high-frequency applications), or nanocrystalline materials. Materials are selected based on required permeability, saturation flux density, core losses, and operating frequency range.
Technical Parameters
ParameterTypical rangeNotes & selection driver
Burden2.5-30 VA
Core Loss<1.5 W/kg at 1.7T, 50Hz
Accuracy Class0.1, 0.2, 0.5, 1.0, 3.0
Frequency Range50-400 Hz
Insulation ClassClass A to Class H (105°C to 180°C)
Secondary Current1A or 5A standard
Primary Current Range5A-5000A

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards
IEC 61869-2, IEEE C57.13, GB/T 20840.2, ANSI C57.13

Parent Products

This component is used in the following industrial products

Current Transformer

A device that transforms high primary current into a lower, proportional secondary current for measurement and protection purposes.

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Trip Solenoid

Electromagnetic actuator that triggers circuit breaker disconnection when abnormal conditions are detected.

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High Voltage Transformer

Electrical component that steps up input voltage to high voltage levels required for dielectric strength testing

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Engineering Analysis

Risks & Mitigation
  • Core saturation leading to measurement errors
  • Thermal runaway from excessive core losses
  • Mechanical damage to laminations
  • Insulation breakdown between laminations
  • Magnetic aging reducing performance over time
FMEA Triads
Trigger: Excessive primary current exceeding design limits
Failure: Core saturation causing nonlinear output and measurement inaccuracy
Mitigation: Implement overcurrent protection, select core material with higher saturation flux density, and provide adequate derating margins
Trigger: Poor lamination insulation or manufacturing defects
Failure: Increased eddy current losses leading to overheating and reduced efficiency
Mitigation: Implement quality control for lamination insulation, use high-quality insulating coatings, and conduct thermal testing
Trigger: Mechanical stress during installation or operation
Failure: Core deformation altering magnetic properties and causing measurement drift
Mitigation: Design robust mechanical protection, use stress-relieved materials, and implement proper handling procedures

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance
±0.1% to ±3.0% depending on accuracy class, with phase angle error < 10 minutes for precision applications
Test Method
Ratio error testing using precision current sources, phase angle measurement, burden testing, dielectric strength testing (2kV-6kV), and temperature rise testing per IEC 61869-2

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation
Request current drawings, revision history, and a signed specification sheet.
Manufacturing capability
Verify equipment lists, process limits, capacity, and representative production evidence.
Inspection readiness
Confirm test methods, calibrated equipment, sampling plans, and traceable reports.
Supplier transparency
Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Core

Manufacturer profiles associated with Core.

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Frequently Asked Questions

What is the purpose of laminating the core material?

Lamination reduces eddy current losses by creating electrical insulation between thin layers of magnetic material, improving efficiency and reducing heating during operation.

How does core saturation affect current transformer performance?

Core saturation occurs when magnetic flux exceeds the material's capacity, causing nonlinear response and measurement errors. Proper core sizing and material selection prevent saturation under maximum current conditions.

What materials are used for high-frequency current transformer cores?

Amorphous metals and nanocrystalline materials are preferred for high-frequency applications due to their low core losses and excellent high-frequency magnetic properties.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification
This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

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