Electrical properties

GE-films offer excellent insulating properties. Manufacturer use the high dielectric strength, the good insulating- and light resistance as well as the constant dissipation factor of these materials for many electrotechnical and electric components.

Dielectric strength

GE films are especially resistant against breakdown at high-electric voltage. Therefore the effective dielectric strength depends on the film thickness, as shown in chart 11. All films meet comparable values at same thicknesses, and this by being nearly uninfluenced by moisture and thermal ageing. The standard for the maximum high-voltage resistance is calculated by multiplying the dielectric strength (kV/mm) by the film thickness (mm).

Picture 3: dielectric strength as a function of the film thickness

Chart 11: dielectric strength (kV/mm) according to ASTM D149

Dielectric constant

All Lexan® films have a dielectric constant of 60Hz and 0 up to 120°C in the area between 2.95 and 3.05. Even water absorption and saturation do not influence the value.

Picture 4:

Dissipation factor

The dissipation factor (or tangent of the loss angle between applied voltage and resulting current wave) is nearly equal for all Lexan® films. Between room temperature and 100°C it is about 0.001 (0.1%), increases then at 140°C up to 0.002 and above 150°C it increases significantly.
The consequences of the rate to the dissipation factor are illustrated in chart 6.

Diagram 5: Dissipation factor of Lexan® in dependency of the temperature at 60Hz

Vorlume- and surface resistance

Lexan® films are especially resistant against power along their surface as well as against electrical continuity. This applies for direct- and alternating current. Water absorption till saturation and typical thermal ageing just have a negligible influence to these two properties.

Diagram 7: Consequences of the temperature to the volume resistivity of Lexan®

Arc resistance of Lexan films

The resistance of film surfaces against the influence of high-current arcs varies according to the film model: Qualities without fire protection, like Lexan® 8010, are generally more resistant than others with fire protection.

Picture 7:

Performance lever (PLC) according to UL746A

The PLC of the Underwriter Laboratories define power ranges for different electrical properties, “which are based on medium test values (and do not state exact numeral results) to avoid the impression of immoderate precision and tendencies.”
The PLC according to UL and/or ASTM are also registered on the “yellow card” of the UL: Chart 12 states the levels for GE films; chart 13 to 17 states the unique PLC.

Chart 13

Chart 14

Chart 15

Chart 16

Chart 17