🔍 Key Concepts

• Dielectric strength: the ability of an insulating fluid to resist electrical breakdown (insulation quality) • Effect of water/moisture on insulation properties of oils used in transformers and machinery • Relationship between purity/contamination of lube oil and its ability to act as an insulator

💭 Think About

• Think about whether water is a good electrical insulator or a conductor compared with clean, dry oil. • If moisture is added to lube oil, does that make the oil a better or worse insulator? How would that affect its breakdown voltage? • Consider what happens in electrical equipment if the insulating oil becomes contaminated—are you more worried about arcing and breakdown, or less?

✅ Before You Answer

• Clarify in your mind that dielectric strength refers to insulation quality (resistance to breakdown under voltage). • Recall that contaminants like water usually change both viscosity and electrical properties, but what is the direct effect on insulation? • Before choosing, ask: with more moisture, is the oil more likely or less likely to allow an electrical path to form? This tells you if dielectric strength goes up, down, or stays the same.