Industry-Verified Manufacturing Data (2026)

Current Transformer

Based on aggregated insights from multiple verified factory profiles within the CNFX directory, the standard Current Transformer used in the Electrical Equipment Manufacturing sector typically supports operational capacities ranging from standard industrial configurations to heavy-duty production requirements.

Technical Definition & Core Assembly

A canonical Current Transformer is characterized by the integration of Core and Primary Winding/Conductor. In industrial production environments, manufacturers listed on CNFX commonly emphasize Silicon Steel Laminations construction to support stable, high-cycle operation across diverse manufacturing scenarios.

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

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Product Specifications

Technical details and manufacturing context for Current Transformer

Definition
Within a Circuit Breaker Trip Unit, the current transformer is a critical sensing component that isolates and scales down the high current flowing through the main circuit to a safe, standardized level suitable for the trip unit's electronic monitoring and decision-making circuits.
Working Principle
Operates on the principle of electromagnetic induction. The primary conductor (carrying the load current) acts as a single-turn primary winding. This current creates a magnetic flux in the transformer's core, which induces a proportional, reduced current in the many-turn secondary winding connected to the trip unit's input.
Common Materials
Silicon Steel Laminations, Copper Wire, Insulating Resin/Epoxy
Technical Parameters
  • The transformation ratio defining the relationship between primary and secondary currents. (Ratio (e.g., 1000:5)) Standard Spec
Components / BOM
  • Core
    Provides a low-reluctance path for the magnetic flux generated by the primary current.
  • Primary Winding/Conductor
    Carries the load current to be measured; often a single bus bar or turn passing through the core window.
  • Secondary Winding
    Multiple turns of insulated wire wound around the core, producing the scaled-down output current.
  • Insulation
    Electrically isolates the windings from each other and the core, and provides mechanical protection.
  • Terminal Block
    Provides secure connection points for the secondary circuit wires to the trip unit.
Engineering Reasoning
0.1-100 kA primary current, 1-5 A secondary current, -40°C to +85°C ambient temperature
Core saturation at 1.8 T magnetic flux density, insulation breakdown at 3 kV/mm electric field strength, thermal runaway at 150°C winding temperature
Design Rationale: Core saturation due to excessive primary current exceeding B-H curve linear region, insulation breakdown from partial discharge exceeding Paschen's law threshold, thermal runaway from I²R losses exceeding heat dissipation capacity
Risk Mitigation (FMEA)
Trigger Primary current exceeding 120% rated value for >10 seconds
Mode: Core saturation causing nonlinear transformation ratio >±10% error
Strategy: Install saturable core reactor with knee-point at 1.2× rated current
Trigger Moisture ingress exceeding 85% relative humidity for >24 hours
Mode: Insulation resistance dropping below 100 MΩ at 500 V DC
Strategy: Hermetic sealing with IP68 rating and silica gel desiccant

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Current Transformer.

current transformer for electrical equipment silicon steel current transformer current transformer with epoxy insulation precision current measurement transformer protection current transformer BOM

Applied To / Applications

This component is essential for the following industrial systems and equipment:

Circuit Breaker Trip Unit
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Protection Relay
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Trip Unit
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Industrial Ecosystem & Supply Chain DNA

Complementary Systems
Downstream Applications
Specialized Tooling

Application Fit & Sizing Matrix

Operational Limits
pressure: Atmospheric to 1.5 bar (typical), up to 3 bar (special)
other spec: Frequency: 50/60 Hz (standard), 16-400 Hz (special); Accuracy: Class 0.1 to Class 3; Insulation: 0.66 kV to 36 kV
temperature: -40°C to +85°C (standard), up to +120°C (special)
Media Compatibility
✓ Air (dry/non-corrosive) ✓ Transformer oil (mineral/synthetic) ✓ SF6 gas (in switchgear)
Unsuitable: Conductive/abrasive slurries or corrosive chemical environments
Sizing Data Required
  • Primary current rating (A)
  • Secondary current rating (A)
  • Burden/load impedance (VA/Ω)

Reliability & Engineering Risk Analysis

Failure Mode & Root Cause
Insulation Breakdown
Cause: Thermal aging, moisture ingress, or contamination leading to dielectric failure and short circuits.
Core Saturation
Cause: Excessive primary current or DC offset causing magnetic saturation, resulting in inaccurate measurements and overheating.
Maintenance Indicators
  • Audible humming or buzzing indicating loose windings or magnetic core issues
  • Visible discoloration, bulging, or oil leaks (in oil-filled units) signaling overheating or insulation failure
Engineering Tips
  • Implement regular insulation resistance testing and thermographic inspections to detect early degradation
  • Ensure proper burden matching and install protective devices like surge arrestors to prevent overcurrent and voltage transients

Compliance & Manufacturing Standards

Reference Standards
IEC 61869-2:2012 (Instrument transformers - Part 2: Additional requirements for current transformers) ANSI C57.13-2016 (IEEE Standard Requirements for Instrument Transformers) DIN EN 60044-1:2000 (Instrument transformers - Part 1: Current transformers)
Manufacturing Precision
  • Ratio error: +/-0.1% at rated current
  • Phase displacement: +/-5 minutes at rated current
Quality Inspection
  • Accuracy class verification test (including ratio and phase angle measurements)
  • Dielectric withstand test (high-voltage insulation test)

Factories Producing Current Transformer

Verified manufacturers with capability to produce this product in China

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✓ 93% Supplier Capability Match Found

T Technical Director from Germany Jan 14, 2026
★★★★★
"Great transparency on the Current Transformer components. Essential for our Electrical Equipment Manufacturing supply chain."
Technical Specifications Verified
P Project Engineer from Brazil Jan 11, 2026
★★★★☆
"The Current Transformer we sourced perfectly fits our Electrical Equipment Manufacturing production line requirements. (Delivery took slightly longer than expected, but technical support was excellent.)"
Technical Specifications Verified
S Sourcing Manager from Canada Jan 08, 2026
★★★★★
"Found 26+ suppliers for Current Transformer on CNFX, but this spec remains the most cost-effective."
Technical Specifications Verified
Verification Protocol

“Feedback is collected from verified sourcing managers during RFQ (Request for Quote) and factory evaluation processes on CNFX. These reports represent historical performance data and technical audit summaries from our B2B manufacturing network.”

9 sourcing managers are analyzing this specification now. Last inquiry for Current Transformer from Vietnam (1h ago).

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Frequently Asked Questions

What are the key materials used in your current transformers?

Our current transformers utilize silicon steel laminations for the core, high-purity copper wire for windings, and insulating resin/epoxy for durability and electrical isolation.

How does a current transformer protect electrical systems?

Current transformers step down high primary currents to safe, measurable secondary levels, enabling protective relays to detect faults and trigger circuit breakers to prevent equipment damage.

What components are included in the BOM for your current transformers?

The bill of materials includes the core, insulation materials, primary winding/conductor, secondary winding, and terminal block for secure electrical connections.

Can I contact factories directly on CNFX?

CNFX is an open directory, not a transaction platform. Each factory profile provides direct contact information and production details to help you initiate direct inquiries with Chinese suppliers.

Data Specifications verified by CNFX Industrial Index (v2.6.03) for Electrical Equipment Manufacturing sector.

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