Magnetic Wire
Product Classification & Technical Specifications
Enameled Wire
Product Description:
Manufactured using high-purity oxygen-free copper rod or electrical aluminum rod through continuous drawing, vacuum annealing, and multi-layer precision coating and baking processes. The enamel film is uniform, continuous, and firmly adhered to the conductor, offering excellent electrical insulation and mechanical winding properties, suitable for high-speed automated winding equipment.
Technical Parameters:
|
Parameter |
Standard Parameters |
Custom Options |
|
Conductor Material |
Oxygen-Free Copper (Purity ≥99.95%), Electrical Aluminum |
Alloy Copper, Tin-Plated Copper |
|
Conductor Specifications |
Round Wire Φ0.10-5.00mm; Rectangular Wire: a-side 0.8-5.6mm, b-side 2.0-16mm |
Customized per drawing |
|
Insulation Type |
Polyester, Polyurethane, Polyesterimide, Polyimide |
Composite Coating, Self-Bonding Layer |
|
Insulation Thickness |
Grade 1, 2, 3 (IEC 60317) |
Special thickness custom |
|
Thermal Class |
155°C (F), 180°C (H), 200°C (C), 220°C (C+) |
Selection based on operating conditions |
|
Applicable Standards |
IEC 60317-0-1, GB/T 6109, NEMA MW 1000 |
Custom standards available |
Features & Advantages:
● High Thermal Shock Resistance: Enamel film remains soft and non-adhesive after transformer vacuum drying process (140°C/48h).
● Excellent Adhesion: Enamel film does not crack after high-speed winding, suitable for automated production.
● Dielectric Strength: Breakdown voltage ≥1.2 times the IEC standard requirement.
● Surface Quality: Precisely controlled roundness for round wires and R-angle for rectangular wires, reducing winding stress.
Paper-Insulated Winding Wire
Product Description:
Copper or aluminum conductors tightly wrapped with multiple layers of high-voltage cable paper to form an oil-paper composite insulation structure. The insulating paper is vacuum-dried and has excellent compatibility with transformer oil, suitable for oil-immersed power transformers and reactors.
Technical Parameters:
|
Parameter |
Standard Parameters |
Custom Options |
|
Conductor Material |
Oxygen-Free Copper, Electrical Aluminum |
Half-Hard Copper, Aluminum Alloy |
|
Conductor Specifications |
Round Wire Φ1.0-5.0mm; Rectangular Wire: a-side 1.0-5.6mm, b-side 3.0-16mm |
Non-standard sizes custom |
|
Insulation Material |
High-Voltage Cable Paper, Telephone Paper |
Imported Dennison Paper, Crepe Paper |
|
Insulation Thickness |
0.3mm - 3.0mm (based on voltage level) |
Multi-layer composite structure |
|
Wrapping Method |
Overlap Winding, Gap Winding |
Adjustable overlap ratio |
|
Applicable Standards |
IEC 60317-27, GB/T 7673 |
— |
Features & Advantages:
● Excellent Oil Permeability: Formed oil passages between insulation paper layers for effective heat dissipation.
● Low Dielectric Loss: tanδ ≤ 0.002 (in oil at 100°C).
● Partial Discharge Control: Optimized wrapping tightness meets transformer PD requirements.
● Oil Resistance: Insulation paper compatibility with transformer oil verified by type tests.
Glass Fiber Wrapped Wire
Product Description:
Multi-layer wrapping of E-glass fibers around the conductor, followed by impregnation with high-temperature insulating varnish to form a compact, void-free composite insulation layer. Suitable for dry-type transformers, traction motors, and mining motors.
Technical Parameters:
|
Parameter |
Standard Parameters |
Custom Options |
|
Conductor Material |
Oxygen-Free Copper, Electrical Aluminum |
Aluminum Alloy |
|
Conductor Specifications |
Round Wire Φ1.0-5.0mm; Rectangular Wire: a-side 1.0-5.6mm, b-side 3.0-16mm |
Non-standard custom |
|
Insulation Material |
ECR E-Glass Fiber |
High-Silica Glass Fiber |
|
Impregnating Varnish |
Class H (180°C), Class C (220°C) Silicone Varnish |
Eco-friendly impregnating varnish |
|
Insulation Structure |
Single Glass Wrap, Double Glass Wrap |
Enameled + Glass Wrap Composite |
|
Applicable Standards |
IEC 60317-31, GB/T 7672 |
— |
Features & Advantages:
● Void-Free Insulation: Impregnating varnish fully fills fiber gaps, offering excellent corona resistance.
● Strong Overload Capability: Suitable for frequent start-up and overload conditions.
● Environmental Adaptability: High humidity and contamination resistance, suitable for indoor/outdoor use.
● High Mechanical Strength: Glass fiber layers provide additional tensile and abrasion protection.
Film-Insulated Winding Wire
Product Description:
Multi-layer wrapping of polyimide or polyester film around the conductor provides high mechanical and dielectric strength protection. Suitable for traction transformers, mining transformers, and special motors.
Technical Parameters:
|
Parameter |
Standard Parameters |
Custom Options |
|
Conductor Material |
Oxygen-Free Copper, Electrical Aluminum |
Half-Hard Copper |
|
Conductor Specifications |
Rectangular Wire: a-side 1.0-5.6mm, b-side 3.0-16mm |
Shaped Conductors |
|
Insulation Material |
Polyimide Film, Polyester Film |
Composite Film, Nomex Paper |
|
Insulation Thickness |
0.2mm - 2.0mm |
Multi-layer composite structure |
|
Thermal Class |
Class H (180°C), Class C (220°C) |
— |
|
Applicable Standards |
IEC 60317-0-2 |
— |
Features & Advantages:
● Extremely High Mechanical Strength: Puncture and shear resistance, suitable for demanding winding processes.
● Thin Insulation Layer: High space factor, reduces equipment size.
● High Partial Discharge Inception Voltage: Suitable for medium/high voltage motors.
● Radiation and Low-Temperature Resistance: Suitable for special operating conditions.
Continuously Transposed Conductors (CTC)
Product Description:
Multiple enameled rectangular wires arranged in a specific pattern, continuously transposed periodically on the wide side, and wrapped with insulating paper or mesh fabric. This structure significantly reduces eddy current and circulating current losses in the winding and enhances the transformer's short-circuit withstand capability. Suitable for large power transformers (220kV and above), generators, and converter transformers.
Technical Parameters:
|
Parameter |
Standard Parameters |
Custom Options |
|
Conductor Material |
Half-Hard Copper (Rp0.2 100-180 MPa controllable) |
Oxygen-Free Copper, Aluminum |
|
Number of Strands |
5 - 83 strands |
Designed based on capacity |
|
Strand Specifications |
Rectangular Wire: a-side 1.0-2.5mm, b-side 3.0-10.0mm |
Width-to-thickness ratio optimization |
|
Strand Insulation |
Formvar, Polyesterimide |
Composite coating |
|
Transposition Pitch |
30-120mm (precisely controlled) |
Designed per requirements |
|
Outer Insulation |
Insulating Paper, Mesh Fabric, DDP Insulation |
Multi-layer composite |
|
Short-Time Temperature |
250°C (under short-circuit conditions) |
— |
|
Applicable Standards |
IEC 60317-61, GB/T 18844.1 |
— |
Features & Advantages:
● Low Losses: Transposition structure effectively reduces circulating and eddy current losses.
● Short-Circuit Withstand Capability: Half-hard copper conductors + overall bonded structure resist short-circuit electromagnetic forces.
● High Space Factor: Optimized arrangement improves core window utilization.
● Heat Dissipation: Outer insulation layers form oil passages for uniform cooling.
● Mechanical Integrity: Cured structure forms a rigid unit, easy to transport and wind.
Manufacturing Process & Quality Assurance
Production Process Flow
|
Process |
Key Control Points |
In-Line Inspection |
|
Drawing |
Continuous drawing, die precision control |
Conductor diameter online monitoring |
|
Annealing |
Continuous annealing, stress relief |
Elongation, conductivity testing |
|
Coating/Baking |
Horizontal/vertical enameling machine, multi-layer coating/baking, computer temperature control |
Film thickness scanning, pinhole detection |
|
Wrapping |
Constant tension control, precision wrapping head |
Wrap pitch, tension real-time monitoring |
|
Take-up/Re-spooling |
Automatic traverse, avoids wire crossing |
Visual inspection, length measurement |
Quality Inspection System
Incoming Quality Control (IQC)
Copper/Aluminum Rod: Chemical composition analysis, conductivity test, elongation test.
Insulation Materials: Thickness, tensile strength, dielectric strength, thermal stability.
In-Process Quality Control (IPQC)
Film Continuity: Pinhole count sampling per shift.
Insulation Thickness: Micrometer/microscope measurement.
Flexibility: Winding test, elongation test.
Outgoing Quality Control (OQC): 100% performed per batch
DC Resistance Test
Breakdown Voltage Test
Adhesion Test (Rapid elongation/peel)
Visual & Dimensional Inspection
Type Testing: Regularly conducted by third-party or in-house lab
Thermal Shock Test
Softening Breakdown Test
Solvent Resistance Test
Partial Discharge Test
Refrigerant Extraction Test
Simulated Transformer Short-Circuit Thermal Stability Test
Quality Commitment
Standard Compliance
Committed to 100% compliance with applicable IEC, GB, NEMA, and other standards.
01
Traceability
Each spool has a unique serial number traceable to raw material batch, production machine, and operator.
02
Warranty Period
18 months from delivery date or 12 months from equipment commissioning (whichever comes first).
03
Failure Commitment
During warranty, unconditional return/replacement for insulation failures caused by material or workmanship defects, covering resulting direct losses.
04
Response Mechanism
48-hour rapid response for quality issues, 72-hour on-site support.
05
Product Certifications
|
Certification |
Standard/Organization |
Scope |
|
Quality Management System |
ISO 9001:2015 |
All Series |
|
Environmental Management System |
ISO 14001:2015 |
All Series |
|
Occupational Health & Safety |
ISO 45001:2018 |
All Series |
|
Product Safety Certification |
UL 1446 Insulation System |
Enameled Wire, CTC |
|
Environmental Compliance |
RoHS 2.0, REACH |
All Series |
|
International Standard |
IEC 60317 Series |
All Series |
|
National Standard |
GB/T 6109, GB/T 7673, GB/T 18844 |
All Series |
Customization Capability & Technical Development (OEM/ODM)
Technical Design Support
Winding Optimization
Provides wire width-to-thickness ratio recommendations based on transformer core window height and radial dimensions to optimize space factor.
Insulation Matching
Recommends optimal insulation structure and material combinations based on voltage level and operating conditions.
Loss Calculation
Assists in evaluating winding eddy current and circulating current losses, providing selection recommendations.
Product Customization Options
|
Customization Dimension |
Options
|
|
Conductor Material |
Oxygen-Free Copper, Electrical Aluminum, Aluminum Alloy, Tin-Plated Copper, Half-Hard Copper (controllable strength) |
|
Conductor Dimensions |
Rectangular wire width/thickness ratio, R-angle radius, shaped cross-sections |
|
Insulation Material |
Imported Dennison Paper, Domestic Special Paper, Polyimide Film, Nomex Paper, Mica Tape |
|
Insulation Structure |
Single/Multi-layer, Composite Insulation, Self-Bonding Layer, Abrasion-Resistant Layer |
|
Continuously Transposed Conductor |
Strand count, pitch, width/thickness ratio, outer insulation material, overall bonded / non-bonded |
|
Special Properties |
Refrigerant-resistant formulation, Transformer oil-resistant formulation, Low friction coefficient coating |
Sample Support
Sample Policy
Supports trial production of small length samples (0.5kg–10kg) for winding process validation or type test pre-testing.
Sample Lead Time
3-5 working days for standard specifications; 7-15 working days for special custom orders.
Sample Cost
Free for standard samples (limited to 1-2 specifications); mold fee charged for special custom orders (refunded upon mass production).
Project Execution & Full Lifecycle Services
Packaging Solutions
|
Packaging Type |
Application |
Technical Description |
|
Standard Packaging |
Domestic transport, general warehousing |
Spool + stretch film sealing, moisture and dust protection |
|
Export Packaging |
Sea freight, long-distance transport |
Fumigated / heat-treated wooden crate + internal cushioning material |
|
Anti-Oxidation Packaging |
High humidity areas, long-term storage |
Vacuum packaging / nitrogen packaging + desiccant |
|
Special Packaging |
CTC, large spools |
Custom wooden/steel frame + fixed strapping |
Labeling Information: Each spool includes a label with: specification, batch number, net weight, production date, applicable standard, inspection status.
Logistics & Transport
Partners
Long-term cooperation with professional logistics providers and heavy transport companies.
01
Transport Modes
Road, sea, air; door-to-door service available.
02
Insurance
Cargo fully insured based on value.
03
Tracking
Full logistics tracking with real-time updates.
04
Special Requirements
Flatbed trucks used for large spools (e.g., CTC) to avoid stacking pressure.
05
Installation & Winding Guidance
For complex products such as CTC and large wrapped wires, the following technical support is provided:
● Receiving Inspection Guidance: Instructs customers on inspecting product appearance and quantity.
● Pre-Winding Preparation: Confirms winding machine tension settings, wire pre-treatment requirements (e.g., drying).
● First Article Verification Support: Assists in completing first spool winding to confirm quality.
● On-Site Guidance: Engineers can be dispatched to guide CTC winding, transposition, and welding processes.
● Exception Handling: Remote diagnostics or on-site support for winding abnormalities.
Training
Training Modules:
|
Training Topic |
Key Content |
Format |
|
Storage Management |
Temperature/humidity requirements, stacking height, oxidation prevention, FIFO |
On-site/Manual |
|
Pre-Winding Preparation |
Unpacking inspection, pre-treatment (e.g., drying), winding machine parameter setup |
On-site/Video |
|
Winding Process Guidance |
Tension control, winding speed, wire arrangement, joint handling |
On-site/Video |
|
Welding/Terminal Process |
Welding temperature, time control, terminal selection |
On-site/Manual |
|
Quality Issue Identification |
Common defect identification, cause analysis, preventive measures |
On-site/Case Study |
Training Materials: Provided with "Product Usage & Maintenance Manual" and "Winding Process Work Instructions."
After-Sales Service
Service Channels
400 technical hotline + WeChat service group + email support.
01
Response Time
Consultation response within 2 hours; quality issue handling process initiated within 48 hours.
02
On-Site Service
Technical personnel arrive within 72 hours domestically (if on-site handling required).
03
Service Records
Written report provided for each service, signed by customer.
04
Maintenance Guidance
Operation Recommendations
Provides recommendations for temperature monitoring and partial discharge monitoring of windings during equipment operation.
Failure Analysis Support
Assists in analyzing whether winding wire is the cause if customer equipment fails, providing corrective solutions.
Spare Parts Recommendations
Recommends quantity and specifications of spare spools based on equipment criticality.
Spare Parts Support
The following consumables are available:
Same-batch spare wire (ensures insulation consistency for repairs)
1
>>
Welding materials (special electrodes, flux)
2
>>
Insulating varnish (touch-up pens, canned varnish)
3
>>
Insulating tape / binding tape
4
>>
Terminals
5
Application Fields
1. Power Systems
Oil-Immersed Power Transformers
10kV distribution transformers – 1000kV UHV converter transformers
Dry-Type Distribution Transformers
SCB series, amorphous alloy transformers
Reactors
Shunt reactors, current-limiting reactors, filter reactors
Instrument Transformers
Current transformers, voltage transformers
2. Industrial Electrical
Special Transformers
Furnace transformers, rectifier transformers, mine explosion-proof transformers
High-Voltage Motors
6kV, 10kV class high-voltage induction motors
Generators
Industrial generator sets, hydro/turbo generators
3 Rail Transit
Traction Transformers: EMU, electric locomotive traction transformers
Onboard Auxiliary Transformers
Traction Motors: AC traction motors
4 New Energy
Photovoltaic: Reactors for PV inverters, step-up transformers
Wind Power: Stator windings for DFIG / direct-drive wind turbines
Energy Storage: Reactors and transformers for energy storage converters
5 General Electrical
Relays, Contactors
Electromagnetic coils, brake coils
Sensors, actuators
Business Cooperation Models
Pricing Mechanism
Pricing Model
Floating pricing based on "raw material cost + fixed processing fee."
Raw Material Benchmark
Based on LME copper price or domestic non-ferrous metal exchange average price.
Processing Fee Composition
Includes drawing, annealing, insulation, testing, packaging, management, and reasonable profit.
Quotation Validity
3-5 working days (re-confirmed during periods of significant raw material price fluctuation).
Payment Terms
|
Transaction Type |
Terms |
Applicable Scope |
|
T/T |
30% advance + 70% before shipment |
First-time cooperation, regular orders |
|
L/C |
Irrevocable L/C at sight / usance |
Export orders, high-value orders |
|
Western Union |
100% prepayment |
Small sample orders |
Support for Partners:
|
Support Type |
Description |
Support Type |
|
Territory Protection |
Exclusive authorization, strict regional division, avoids internal competition |
Territory Protection |
|
Product Support |
Exclusive model protection, joint bidding support, project registration system |
Product Support |
|
Technical Support |
Regular product and technical training, assists customer technical exchanges |
Technical Support |
|
Pricing Support |
Exclusive tiered pricing system, special bid pricing support |
Pricing Support |
|
Marketing Support |
Samples, catalogs, demo materials, joint trade show participation |
Marketing Support |
|
After-Sales Support |
Partner service team training, joint after-sales response |
After-Sales Support |
Partnership Process:
Initial Contact → Qualification Review → Partnership Agreement Signing → Technical Training → Authorization Certificate Issuance → Market Launch
FAQ – Common Technical Questions
Q: How does CTC prevent strand loosening after a short circuit?
A: We control this from two aspects: 1) Conductors use half-hard copper with controlled yield strength (Rp0.2 120–180 MPa) for improved deformation resistance; 2) Optimized transposition pitch and curing process for formvar/epoxy ensure the conductor becomes a rigid, monolithic structure after heat curing. Our CTC has been successfully used by major domestic transformer manufacturers to pass short-circuit tests at the National Transformer Quality Supervision and Testing Center.
Q: How should paper-insulated wire be stored to prevent moisture? What to do if it gets damp?
A: Store in a clean environment at 5–35°C, relative humidity ≤70%, avoid direct sunlight, stacking height ≤3 layers. If dampened, do not place directly into transformer oil. Vacuum drying is required: temperature 105–110°C, vacuum ≤100Pa, duration 8–24 hours depending on moisture level. Contact us for the "Insulated Paper Wire Dampness Treatment Work Instruction."
Q: What is the achievable R-angle for rectangular enameled wire? How to avoid thin coating at the R-angle?
A: The R-angle depends on the wire width/thickness ratio, typically about a-side/2, and can be minimized to 0.5mm (depending on specifications). To address coating challenges at the R-angle, we use a "electrostatic spray + die coating" combined process and regularly monitor the R-angle film thickness using online microscopes to ensure it is not less than 50% of the B-side (wide side) film thickness. Annealing process is also optimized to avoid stress concentration at the R-angle.
Q: Do you support small batch sample testing? What is the minimum order quantity?
A: Yes, we strongly support customer trials before mass production. For standard specifications, the minimum sample quantity can be as low as 1kg or 5 meters. For special custom products, feasibility regarding tooling and process needs to be discussed; the minimum order quantity depends on the specific case. Our application engineers can provide remote technical support during sample testing.
Q: What is the after-sales process if a quality issue occurs during use?
A: We initiate a 48-hour rapid response mechanism: 1) Establish communication channel within 2 hours of feedback; 2) Complete preliminary cause analysis within 24 hours; 3) Issue resolution plan or dispatch technical personnel within 48 hours. For on-site handling, arrival within 72 hours domestically. If confirmed as our responsibility, we will replace, return, or provide compensation according to our quality commitment.
Q: Can your products support the manufacturer during short-circuit testing?
A: Yes. Our magnet wires have been successfully used by major domestic transformer manufacturers (e.g., TBEA, SEPCO, XD, Baobian) to pass short-circuit tests at the National Transformer Quality Supervision and Testing Centers (Shenyang, Wuhan). For test support, we can provide relevant material certifications and technical assistance.
Q: Can the packaging withstand long-distance sea freight?
A: Absolutely. For sea freight, we provide export-grade fumigated/heat-treated wooden crates with internal cushioning and moisture protection. Spools are securely fixed to ensure products remain intact after long sea voyages and multiple handling. All export packaging complies with IMDG Code and relevant national quarantine requirements.
Q: Do you provide on-site technical training?
A: Yes, for bulk procurement customers or partners, we can arrange for application engineers to provide on-site technical exchange and winding process training. Training content includes storage specifications, winding parameter settings, common issue handling, etc., to help your production personnel better use our products. A written summary is provided after training.
Q: How to select the appropriate thermal class for magnet wire?
A: The selection is primarily based on the transformer/motor's designed temperature rise and insulation system. Class F (155°C) is suitable for standard distribution transformers; Class H (180°C) for dry-type transformers and traction motors; Class C (200°C and above) for special motors and overload conditions. Provide equipment parameters, and we can assist in determining the optimal selection.
Q: What is the elongation achievable for your magnet wire conductors?
A: Elongation for oxygen-free copper wire is typically ≥30%; for half-hard copper wire, it is controlled between 3–10% depending on strength requirements; for aluminum wire, it is ≥15%. Specific values can be adjusted based on your winding process requirements.
Document Version: V3.0 (High-Voltage Electrical Equipment Technical Documentation)
Basis: IEC 60317 Series, GB/T 6109, GB/T 7673, GB/T 18844
Date: May 2024
Note: The content on this page is technical description. Specific product parameters are subject to the finalized technical agreement.
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