# Electrical Properties

## 1. Dielectric Breakdown Strength for Various Product Numbers

Lumirror™ has an extremely high dielectric breakdown strength.

Fig. 1 shows the breakdown voltage for various Lumirror™ product numbers measured at a frequency of 60 Hz.

The measurement method was JIS C 2318-72 with the test performed at 20°C.

Fig. 1 shows the breakdown voltage for each unit thickness, while the dielectric breakdown strength is shown in Fig. 2.

## 2. Change in Dielectric Breakdown Strength Based on Temperature

Up to approx. 100°C, the dielectric breakdown strength of Lumirror™ hardly changes. Even at 150°C, it still maintains 90% of its performance at room temperature.

Fig. 3 shows the changes in #25 (25 μ) and #50 (50 μ) Lumirror™ dielectric breakdown strength based on temperature.

## 3. Change in Dielectric Breakdown Strength Based on Humidity

Up to approx. 50% RH, the dielectric breakdown strength of Lumirror™ hardly changes. Even at 100% RH, it still maintains 80% of its performance at normal humidity.

Fig. 4 shows the changes in #50 (50 μ) Lumirror™ dielectric breakdown strength at 20°C and 40°C based on humidity.

## 4. Change in Dielectric Constant Based on Frequency

Fig. 5 shows the change in dielectric constant for #25 (25 μ) Lumirror™ at various temperatures based on frequency.

The measurement method is JIS C 2318-72.

It should be noted that any product number (thickness) of Lumirror™ displays almost the same dielectric constant.

## 5. Change in Dielectric Constant Based on Temperature

Fig. 6 shows the change in dielectric constant for #25 (25 μ) Lumirror™ at 1 KHz based on temperature.

The measurement method is JIS C 2318-72.

## 6. Change in Dissipation Factor Based on Frequency

Fig. 7 shows the change in dissipation factor for #25 (25 μ) Lumirror™ at various temperatures based on frequency.

The measurement method is JIS C 2318-72.

It should be noted that any product number (thickness) of Lumirror™ displays almost the same dissipation factor.

## 7. Change in Dissipation Factor Based on Temperature

Fig. 8 shows the change in dissipation factor for #25 (25 μ) Lumirror™ at 1 KHz based on temperature.

The measurement method is JIS C 2318-72.

## 8. Change in Volume Resistivity Based on Temperature

Fig. 9 shows the change in #25 (25 μ) and #50 (50 μ) Lumirror™ volume resistivity based on temperature. The measurement method is JIS C 2318-72.

## 9. Change in Surface Resistivity Based on Temperature

Fig. 10 shows the change in #25 (25 μ) and #50 (50 μ) Lumirror™ surface resistivity based on temperature.

The measurement method is ASTM D 257-66.

## 10. Corona Discharge Voltage for Various Product Numbers

Fig. 11 shows the corona discharge inception voltage and discharge extinction voltage for various Lumirror™ product numbers.

Figures 12 and 13 show the measurement circuit and measurement electrodes.

## 11. Corona Resistant Life

Fig. 14 shows the time taken for Lumirror™ to undergo dielectric breakdown due to corona discharge generated at a frequency of 60 Hz, or in other words, the change in corona resistant life based on electric field strength.

The thickness of the samples measured were #50 (50 μ) and #75 (75 μ), and the measurement method was the IEC (15B) Electrode Method.