Polyester Series

QZ (PEW) Enameled WireClass B & Class F Insulation

130°C and 155°C temperature ratings for transformers, motors, and advanced electrical devices.

YIDA's Polyester Series offers two proven insulation grades designed for the broad needs of today's electrical industry. Class B (130°C) provides dependable insulation for general-purpose applications requiring consistent performance and moderate thermal resistance. Class F (155°C) extends the thermal envelope for more demanding environments in motors, transformers, and advanced electrical devices.

Both grades deliver precise dimensional tolerances across a range of 0.06 – 3.0mm, conforming to IEC 60317, GB/T 6109, and NEMA specifications. The polyester enamel coating provides excellent mechanical toughness and dielectric strength, making it a versatile choice across a wide range of winding applications.

Transformers & Inductors

Reliable insulation for power and signal transformer windings with consistent performance.

Motors & Generators

Stable thermal resistance under continuous cycling in rotating machinery.

Solenoids & Relays

Precise diameter tolerances enabling compact, efficient coil designs.

Consumer Electronics

Cost-effective insulation for high-volume production across diverse form factors.

Whether your project calls for small-gauge windings in compact electronics or larger conductor sizes in industrial transformers, the Polyester Series provides a reliable, cost-effective foundation. Contact our team for custom sizing, volume pricing, and technical support.

YIDA Enameled Copper Wire Insulation Guide

Download Insulation Guide

Technical Specifications

Polyester Series Specifications

Available in Class B (130°C) and Class F (155°C) ratings. All products conform to international standards.

Thermal Class	Insulation Type	YIDA Product Code	Diameter Range (mm)	Diameter Range (AWG)	IEC Standard (60317)	GB/T (6109)	NEMA Standard
130°C	Polyester 130	QZ (PEW)	0.06 – 1.6	#14 – #42	60317-34	6109.7	—
155°C	Polyester 155	QZ (PEW)	0.06 – 3.0	#9 – #42	60317-3	6109.2	MW5-C

Applications

Polyester enameled wire is the workhorse of the electrical industry, used in general-purpose motors, dry-type transformers, household appliances, industrial motors, lighting ballasts, and solenoid valves. Its excellent cost-to-performance ratio makes it the most widely specified insulation for magnet wire applications operating within Class B and Class F temperature limits.

Frequently Asked Questions

What is the difference between Class B (130°C) and Class F (155°C) polyester wire?+

Class B (130°C) polyester wire is designed for general-purpose applications where operating temperatures stay within moderate limits. Class F (155°C) uses a modified polyester resin that extends the thermal envelope by 25°C, suitable for more demanding motor and transformer applications. Class F also offers a wider diameter range (up to 3.0mm) and NEMA MW5-C compliance.

What applications use polyester enameled wire?+

Polyester enameled wire is used extensively in AC and DC motors, dry-type power and distribution transformers, household appliance motors (fans, compressors, pumps), industrial automation equipment, lighting ballasts, and solenoid valves. It is the most cost-effective insulation choice for applications within Class B and F temperature limits.

Is polyester wire suitable for high-humidity environments?+

Polyester enamel provides good moisture resistance and maintains its dielectric properties in moderately humid conditions. For continuously humid or wet environments, the coil assembly should be vacuum-impregnated with varnish to seal moisture out. For extremely harsh conditions, consider upgrading to polyesterimide insulation which offers superior chemical and moisture resistance.

What is the advantage of polyester over polyurethane enameled wire?+

Polyester insulation offers superior mechanical toughness and abrasion resistance compared to polyurethane, making it better suited for motor windings that undergo significant stress during insertion into stator slots. It also has better resistance to solvents and varnishes used in post-winding impregnation. However, polyester is not directly solderable — insulation must be stripped before termination, unlike polyurethane wire.

YIDA Wire has manufactured enameled copper wire since 1984. IATF 16949, ISO 9001, and UL certified. Trusted by industry leaders across 50+ countries. Contact us for specifications →