Litz Film Insulations

Insulation	Rating	AWG	Advantages	Considerations
Polyvinyl Formal	Class 105 MW 15-C	14 - 50	Excellent abrasion resistance Excellent compatibility with transformer oils Good electrical properties Used in Cryogenic Applications	Must be stripped before soldering Should be annealed before application of varnish
Polyurethane	Class 155 MW 79-C Class 180 MW 82-C	30 - 50 24 - 50	Excellent electrical properties for high Q coils Easily solderable 390°C/360°C Excellent film adhesion & flexibility Good moisture & chemical resistance	Not recommended for applications with the possilbility of severe thermal overload
Polyurethane-Nylon	Class 155 MW 80-C Class 180 MW 83-C	10 - 46 25 - 46	Good electrical properties Easily solderable 430°C/39°C Excellent film adhesion & flexibility Improved chemical & mechanical resistance from nylon topcoat Nylon overcoat provides low coefficient of friction	Not recommended for applications with the possiblity of severe thermal overload Nylon topcoat is hygroscopic
Solderable Polyester	Class 180 MW 77-C	14 - 50	Solderable 470°C Excellent thermal properties Good electrical properties Good compatibility with varnishes & solvents Improved thermal overload Good moisture resistance	Low abrasion resistance compared to Nylon & amide imide topcoat materials Preheat before varnishing is recommended
Solderable Polyester Nylon	Class 180 MW 78-C	14-50	Solderable 470°C Excellent thermal properties Good electrical properties Good compatibility with varnishes & solvents Improved thermal overload Good moisture resistance Nylon overcoat provides low coefficient of friction	Nylon topcoat is hygroscopic Preheat before varnishing is recommended
Polyester(amide)(imide)	Class 200 MW 74-C	34 - 44	Excellent flexibility & abrasion resistance Excellent thermal overload Excellent dielectric strength Excellent moisture resistance Good chemical resistance	Must be stripped before soldering Not recommended for use in oil-filled transformers Preheat before varnishing
Polyester/Poly-amideimide Overcoat	Class 200 MW 35-C	8 - 33	Excellent flexibility & abrasion resistance Excellent thermal overload Excellent dielectric strength Excellent moisture resistance Good chemical resistance	Must be stripped before soldering Preheat before varnishing
Polyimide	Class 240 MW 16-C	10 - 30	Excellent flexibility Excellent thermal overload Excellent radiation resistance Excellent chemical compatibility High dielectric strength Adequate abrasion resistance Low outgas	Must be stripped before soldering Must be annealed before varnishing Will solvent craze