Secondary Winding (for transformer): Inductance 1 μH to 100 mH

Component Specifications

Definition

The secondary winding is a crucial component in transformers and isolation devices, consisting of insulated copper or aluminum wire wound around a magnetic core. It functions as the output circuit where electrical energy is transferred from the primary winding via electromagnetic induction, typically stepping voltage up or down according to the turns ratio. In isolation components like optocouplers with transformer isolation, it provides galvanic separation between input and output circuits while maintaining signal integrity.

Working Principle

Operates on Faraday's law of electromagnetic induction. When alternating current flows through the primary winding, it creates a changing magnetic field in the core. This changing field induces a voltage in the secondary winding proportional to the turns ratio (N_secondary/N_primary). The winding design, insulation, and core coupling efficiency determine voltage transformation, power transfer capability, and isolation performance.

Materials

Copper (Cu-ETP) or aluminum (EC grade) conductor with polyurethane, polyester, or polyimide insulation (Class A to H, 105°C to 220°C). Core interface materials include insulating paper, epoxy coating, or varnish for moisture and thermal protection. Terminal connections use tin-plated copper or brass.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Inductance	1 μH to 100 mH
Wire Gauge	AWG 18 to 40
DC Resistance	0.1 Ω to 100 Ω
Dielectric Strength	1500-4000 VAC RMS
Turns Ratio Accuracy	±1% to ±5%
Insulation Resistance	>100 MΩ at 500V DC
Operating Temperature	-40°C to +155°C

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 61558, DIN EN 61558, UL 1446

Parent Products

This component is used in the following industrial products

Isolation Component (Optocoupler/Transformer)

Electrical isolation component that prevents high-voltage transients from damaging low-voltage control circuits in gate driver applications.

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Engineering Analysis

Risks & Mitigation

Insulation breakdown due to overheating
Inter-winding short circuits
Core saturation leading to distorted output
Moisture absorption reducing dielectric strength
Mechanical damage from vibration

FMEA Triads

Trigger: Overcurrent or thermal overload
Failure: Insulation degradation and winding short circuit
Mitigation: Implement thermal protection, use higher temperature insulation materials, and design with adequate current margins

Trigger: Poor winding technique or material defects
Failure: Open circuit or intermittent connections
Mitigation: Quality control during manufacturing, automated winding machines, and 100% electrical testing

Trigger: Environmental contamination
Failure: Reduced insulation resistance and corona discharge
Mitigation: Encapsulation with epoxy or varnish, conformal coating, and controlled manufacturing environment

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Turns ratio tolerance ±1% to ±5%, inductance tolerance ±10% to ±20%, resistance tolerance ±5%

Test Method

Hi-pot testing (dielectric strength), insulation resistance measurement, turns ratio verification using bridge methods, thermal cycling per IEC 60068-2-14

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

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Manufacturers of Secondary Winding (for transformer)

Manufacturer profiles associated with Secondary Winding (for transformer).

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Frequently Asked Questions

What determines the output voltage of a secondary winding?

The output voltage is determined by the turns ratio between secondary and primary windings (V_out = V_in × N_secondary/N_primary) and the core's magnetic coupling efficiency.

How does winding insulation affect transformer performance?

Proper insulation prevents short circuits, maintains dielectric strength, and ensures thermal stability. Higher insulation classes allow operation at elevated temperatures without degradation.

Can secondary windings be used in DC applications?

Secondary windings only work with changing currents (AC or pulsed DC). For DC isolation, additional circuitry like switching converters is required to create alternating magnetic fields.

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.

Secondary Winding (for transformer)