INDUSTRY COMPONENT

Secondary Winding

Secondary winding is the output coil in a current transformer that produces a reduced current proportional to the primary current for measurement and protection.

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Component Specifications

Definition
The secondary winding in a current transformer is a precisely wound coil of insulated copper wire that forms the output circuit. It is designed to produce a standardized secondary current (typically 1A or 5A) that is directly proportional to the primary current flowing through the transformer's core. This component enables safe measurement, monitoring, and protection of high-current systems by isolating measurement circuits from high-voltage primary circuits.
Working Principle
Operates on electromagnetic induction principle where alternating current in the primary winding creates a varying magnetic flux in the core, which induces a proportional current in the secondary winding according to the transformer's turns ratio (Np:Ns).
Materials
High-purity electrolytic copper wire (99.9% Cu) with Class F (155°C) or higher thermal class insulation, typically polyimide or polyester film insulation. Core material is usually grain-oriented silicon steel or nanocrystalline alloy.
Technical Parameters
  • Burden 2.5-30 VA
  • Frequency 50/60 Hz
  • Turns Ratio Typically 100:1 to 5000:1
  • Accuracy Class 0.2, 0.5, 1, 3, 5
  • Thermal Rating 1.2 x rated current continuous
  • Insulation Class Class F (155°C) minimum
  • Rated Secondary Current 1A or 5A
Standards
IEC 61869-2, IEEE C57.13, ANSI C57.13, GB/T 20840.2

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Secondary Winding.

current transformer secondary winding CT secondary coil instrument transformer winding measurement winding protection winding electrical isolation coil Secondary Winding Secondary Winding in Electrical Equipment Manufacturing

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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High Voltage Transformer

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

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Transformer

An electromagnetic device that transfers electrical energy between circuits through electromagnetic induction, typically used to change voltage levels.

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Engineering Analysis

Risks & Mitigation
  • Open-circuit voltage hazards
  • Insulation breakdown
  • Saturation at high currents
  • Thermal overload
  • Incorrect polarity connection
FMEA Triads
Trigger: Open secondary circuit during operation
Failure: Dangerously high induced voltage, insulation breakdown, arcing
Mitigation: Always short-circuit secondary terminals before disconnecting, use shorting switches, implement protective circuits
Trigger: Excessive primary current beyond rating
Failure: Core saturation, waveform distortion, measurement inaccuracy
Mitigation: Select proper accuracy limit factor (ALF), use saturation-resistant core materials, implement overcurrent protection
Trigger: Poor insulation quality or contamination
Failure: Insulation breakdown, short circuits, equipment damage
Mitigation: Use high-temperature insulation materials, implement regular insulation resistance testing, maintain clean environment

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
±0.2% to ±5% depending on accuracy class at rated current and burden
Test Method
Ratio error test, phase displacement test, insulation resistance test, dielectric strength test, burden verification test

Buyer Feedback

★★★★☆ 4.8 / 5.0 (9 reviews)

"Reliable performance in harsh Electrical Equipment Manufacturing environments. No issues with the Secondary Winding so far."

"Testing the Secondary Winding now; the technical reliability results are within 1% of the laboratory datasheet."

"Impressive build quality. Especially the technical reliability is very stable during long-term operation."

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Frequently Asked Questions

What happens if the secondary winding of a current transformer is open-circuited?

Open-circuiting the secondary winding creates dangerously high voltages that can damage insulation, cause arcing, and pose serious safety hazards. Current transformers must never operate with an open secondary circuit.

What is the difference between 1A and 5A secondary windings?

1A secondary windings have more turns and are used for long-distance transmission with lower power loss, while 5A secondary windings have fewer turns and are common for local measurement with standard instruments.

How is secondary winding accuracy class determined?

Accuracy class (0.2, 0.5, 1, etc.) indicates the maximum percentage error at rated current. Class 0.2 has ±0.2% error for metering, while Class 5 has ±5% error for protection applications.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

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