🔍 Key Concepts

• Thermal aging of electrical insulation materials • The empirical rule often used by engineers relating temperature rise to insulation life (sometimes linked to an Arrhenius-type relationship) • Typical design guidance for motors/transformers regarding how small temperature increases affect insulation longevity

💭 Think About

• Think about whether insulation life is very sensitive or only slightly sensitive to temperature increases. • Compare the options: which increase in temperature seems small but could reasonably cause a big reduction in life over long periods? • Engineers sometimes use a simple rule-of-thumb: every fixed, modest rise in temperature cuts life roughly in half. Which option looks like a realistic rule-of-thumb step size?

✅ Before You Answer

• Be sure the temperature change is realistic for engineering rules-of-thumb, not an extreme jump. • Ask whether such a temperature increase would commonly occur in normal equipment operation (e.g., motors, generators, transformers). • Eliminate options that imply the insulation could tolerate very large temperature increases before life is halved; those are usually not consistent with aging behavior.