Litz Wire

www.osco.uk.com What is Litz Wire? Why do you need Litz Wire? Benefi ts of Litz Wire

Litz Wire consists of a number of Typically when manufacturing Motors, Transformers and other individually insulated magnet wires electromagnetic devices, magnetic fi elds are created by current Reduce A.C losses in high-frequency winding in a wire. By raising the frequency, you create stronger fi elds and twisted or braided into a uniform higher coupling resulting in a loss in the materials due to two pattern with the primary benefi t of effects – Skin Effect and Proximity Effect. reducing A.C losses in high frequency windings. OSCO offer unlimited Litz Wire As the frequency rises, the current migrates to the skin and the Increased effi ciency constructions with multiple layers of current is pushed away by the fi eld of its neighbouring strand making the core of the conductor useless. insulation to meet UL voltage withstand requirements. Litz Wire mitigates both the Skin Effect and Proximity Effect Losses. OSCO design with strands that are smaller than the skin depth Mitigation of Skin Effect The enamels commonly used for and transpose those strands throughout the length of the wire. insulating individual strands are The correct size of the skin depth is based on the frequency of the application. Polyurethane and Polyurethane with Mitigation of Proximity Effect a Nylon topcoat because of the low The most important question to consider when designing your electrical losses and ease of solderability Litz Wire is what is your operating frequency for the application? however other insulations can also be This is due to the most well-known benefi t of Litz Wire - a reduction used. In many cases, Litz Wire is insulated of A.C losses. The operating frequency for your application will determine both the Litz construction and the individual wire Minimum Eddy Current Losses with an overall single or double wrap or gauge size. The table below highlights the recommended wire serving, of a textile, but are also available gauge verses frequency for most Litz Wire constructions. unserved. Lowered Operating Temperatures

Recommended Nominal Diameter DC Resistance Single Strand Frequency Wire Gauge over Copper Ohms/M’ (Max) RAC / RDC Reduced Footprint of fi nal product 60 HZ to 1 KHZ 28 AWG .0126 66.37 1.0000 1 KHZ to 10 KHZ 30 AWG .0100 105.82 1.0000 10 KHZ to 20 KHZ 33 AWG .0071 211.70 1.0000 20 KHZ to 50 KHZ 36 AWG .0050 431.90 1.0000 50 KHZ to 100 KHZ 38 AWG .0040 681.90 1.0000 Substantial weight reduction 100 KHZ to 200 KHZ 40 AWG .0031 1152.30 1.0000 200 KHZ to 350 KHZ 42 AWG .0025 1801.0 1.0000 350 KHZ to 850 KHZ 44 AWG .0020 2873.0 1.0003 850 KHZ to 1.4 MHZ 46 AWG .0016 4544.0 1.0003 1.4 MHZ to 2.8 MHZ 48 AWG .0012 7285.0 1.0003 Avoidance of “hot spots”

2 www.osco.uk.com www.osco.uk.com 3 Products Products

Round Type 1 Litz Round Type 2 Litz Round Type 3 Litz Round Type 4 Litz Square Shaped Profiles Cooled Profiles

A single twisting operation with Bundles of twisted wire twisted Insulated bundles of twisted wire Bundles of twisted wire twisted Square Profiled Litz Wire allows Cooled Litz Wire uses a tube core optional outer insulation. together with optional outer twisted together with an optional around a centre fiber core. for the best possible use of the to carry coolant through the Litz, insulation. outer insulation. available winding space in your increasing the current carrying application. capacity of the winding.

Round Type 5 Litz Round Type 6 Litz Rectangular Type 7 Litz Rectangular Type 8 Litz Keystone Shaped Profiles Custom Profiles

Insulated bundles of Type 2 Litz Wire Insulated bundles of Type 4 Litz Wire Insulated wire braided and formed Single insulated strands twisted and Keystone shaped Litz Wire gives the Formed and compacted Litz Wire twisted around a fiber core. twisted around a fiber core. into a rectangular profile.. compressed into a rectangular best wire packing density allowing constructions for applications profile. for the winding of perfect segments. where limited space necessitates a conductor with excellent fill factor and copper density.

4 www.osco.uk.com www.osco.uk.com 5 Film Insulations Tape and Fiber Insulations

Recommended Max. Insulation Rating AWG Advantages Considerations Tape Insulation Characteristics Use Temperature

Polyvinyl Formal Class 105 14 - 50 • Excellent abrasion resistance and compatibility with • Must be stripped before soldering Polyester (PET) Mylar® 135°C • High dielectric strength MW 15-C transformer oils • Should be annealed before (heat sealable • Good abrasion often used as a binder or moisture barrier under extruded • Good electrical properties application of varnish jackets and textile serves or braids. • Used in Cryogenic Applications grades available)

• Excellent electrical properties for high Q coils • Not recommended for Polyurethane Class 155 30 - 50 ® 200°C • Excellent thermal properties • Easily solderable 390°C/360°C applications with the possibility Nomex (aromatic MW 79-C (up to 220°C • Excellent electrical properties • Excellent film adhesion and flexibility of severe thermal overload polyamide) under certain • Excellent compatibility with varnishes, adhesives and transformer fluids. Class 180 24 - 50 • Good moisture and chemical resistance conditions) • Thinner grades are flexible MW 82-C • Good resistance to tearing and abrasion.

Polyurethane- Class 155 10 - 46 • Good electrical properties • Not recommended for Polyimide Kapton® 240°C • Very high dielectric strength Nylon MW 80-C • Easily solderable 430°C/390°C applications with the possibility • Excellent film adhesion and flexibility of severe thermal overload (Heat sealable and (up to 400°C under • Very good chemical resistance • Improved chemical and mechanical resistance • Nylon topcoat is hygroscopic adhesive grades certain conditions) • UL 94 V-0 flame rating Class 180 25 - 46 • Excellent mechanical properties. MW 83-C from nylon topcoat available) • Nylon overcoat provides low coefficient of friction

Solderable Class 180 14 - 50 • Solderable 470°C • Low abrasion resistance Fiberglass Cloth Ultimate operating • Excellent electrical properties at high temperatures Polyester MW 77-C • Excellent thermal properties compared to Nylon and amide temperature determined by • Conformable • Good electrical properties and moisture resistance imide topcoat materials application and glass type • Varnish compatible grades available • Good compatibility with varnishes and solvents • Preheat before varnishing is • Excellent solvent resistance. • Improved thermal overload recommended

Solderable Class 180 14 - 50 • Solderable 470°C • Nylon topcoat is hygroscopic Mica Ultimate operating • Excellent electrical properties at high temperatures Polyester Nylon MW 78-C • Excellent thermal properties • Preheat before varnishing is temperature determined by • Flame resistant • Good electrical properties and compatibility with recommended application and glass type • Retains useful electrical properties during and after exposure to fire. varnishes and solvents • Improved thermal overload • Good moisture resistance Recommended Max. • Nylon overcoat provides low coefficient of friction Fiber Insulation Advantages Limitations Use Temperature

Polyester(amide) Class 200 34 - 44 • Excellent flexibility and abrasion resistance • Must be stripped before soldering Cotton 135°C • Low cost serving • Poor space factor compared to (imide) MW 74-C • Excellent thermal overload, dielectric strength and • Not recommended for use in • Good resistance to abrasion Nylon or Celanese moisture resistance oil-filled transformers • Non-solderable • Good chemical resistance • Preheat before varnishing Nylon 155°C • Good space factor • Hygroscopic Polyester / Class 200 8 - 33 • Excellent flexibility and abrasion resistance • Must be stripped before soldering • Excellent abrasion resistance Poly-amideimide MW 35-C • Excellent thermal overload, dielectric strength and • Preheat before varnishing • Solderable moisture resistance Overcoat ® • Good chemical resistance Dacron (Polyester) 155°C • Good abrasion resistance • Better space factor than Cotton or • Solderable Glass but poorer space factor • Slightly higher maximum than Nylon Polyimide Class 240 10 - 30 • Excellent flexibility, radiation resistance and thermal • Must be stripped before soldering operating temperature than MW 16-C overload • Must be annealed before Nylon • Excellent chemical compatibility varnishing • High dielectric strength • Will solvent craze Nomex® 250°C • Good space factor • Non-solderable • Adequate abrasion resistance (Hi-Temp Aramid) • Good electrical properties • Higher cost than other fibers • Low outgas at high temperatures

Glass 260°C • Good electrical properties • Space factor equivalent to Cotton at high temperatures • Non-solderable Please note that other insulations can be used other than those listed above.

6 www.osco.uk.com www.osco.uk.com 7 Applications Applications

• Stator Windings Litz Applications Litz Wire Type Examples • High Frequency Inductors Wireless Power Transfer 2, 8 • Coils in the Car and in the Road • Power Transformers High Q Circuitry 1, 2, 7, 8 • Tuning Coils • Motor Generators Transformers and Torodial Transformers 1, 2, 8 • Power Transformers • Hybrid Transportation Inductors / Chokes 1, 2, 8 • Motor Drive (Motor Controller) • Solar Inverters • Wind Turbine Generators Motors and Generators 2, 8 • Some Maglev Trains Linear Induction Motors • Vehicle Propulsion • Communication Equipment Permanent Magnet Motors • Oil and Natural Gas Drilling • Automatic Parts Movement • Marine Acoustic Control Systems • Wind Turbines • Induction Heating Equipment High Frequency Power Supplies 1, 2, 3, 8 • Drive the Coils for many of the applications listed • Sonar Equipment Inverters 1, 2, 7, 8 • DC to AC • Radio Transmitter Equipment Grounders 2, 7 • Industrial Machinery • Switch Mode Power Supplies Tuning circuitry in High Power Radio 5, 6 • VLF Radio Transmission

DC / DC Converters 2, 7, 8 • Electric Vehicles •• Ultrasonic Equipment • Automotive • Medical • Linear Motors • Electronics • Sensors Induction Heating Coils 1, 2, 7, 8 • Hospital Plate Warmer • Sealing Bottles (Adhesive Backed Aluminium) • Antennas • Mold Preheat Before Plastic Injection • Molten Metal Processing • Grounding Applications

Ballast 1, 2 • Fluorescent Lighting • Wireless Power Systems Propagation of High Frequency 2, 3, 4, 5 • Leads to Thin Film Deposition Equipment • Electric Vehicle Chargers Power Litz Lead Wire • Leads for Plasma Coating of Glass • Leads to Induction Heating Blanket • High Frequency Chokes Flywheel Energy Storage 2, 7, 8 • Energy Storage • Coils Plasma Containment Coils 2 • Stellarator / Fusion Energy Experiments • High Frequency Motors Specialty Audio All Litz Types • High Fidelity Speaker Wire • Audio Interconnect • Medical Device Chargers

8 www.osco.uk.com www.osco.uk.com 9 Design Solutions

400 HZ to 1 KHz Compactions tailored to your winding window to 90% Type 8 Aspects to 18 to 1

1 KHz to 50 KHz Type 8 Density to 88% Aspects to 7 to 1 Concentric

1 KHz to 850 KHz Type 8 Density to 75% Aspects to 5 to 1 Bunched

1 KHz to 2 MHz Type 8 Density to 70% Aspects to 4.5 to 1 Served

1 KHz to 2 MHz Type 2 Density to 70% Aspects to 1.75 to 1 Formed

1 KHz to 2 MHz Density to 70% Type 7 Aspects to 20 to 1

Type 8 Custom Shapes

10 www.osco.uk.com Testimonials

Vehicle Drivetrain Developer Transformer and Motorsport and Manufacturer of Inductor Manufacturer Motor Drives

“When working with OSCO “We have been trading “OSCO are considered a very on Litz Wire requirements we with OSCO now for valuable partner and their support have always found them a number of years through both the development to be very knowledgeable buying quality wire to phase and through production has with an understanding of suit our manufacturing made a significant difference in our the types of applications the process.” competitive advantage. Their support wire is to be used for. We always exceeds expectations and have no hesitation in working in effect they are an extension of our with OSCO when it comes to organisation. Any organisation that has sourcing wire as they are a very demanding requirements such as pleasure to do business with.” ours should consider using OSCO.”

Specialist Electronic Materials

OSCO Limited, Avant Business Centre, Third Avenue, Bletchley, Milton Keynes, MK1 1DR

T: +44 (0) 1908 376 688 NEW ENGLAND WIRE E: [email protected] TECHNOLOGIES

Manufactured By www.osco.uk.com New England Wire Technologies