🔍 Key Concepts
• Reciprocating air compressor components: bearings, pistons, valves, unloaders, drive motor
• Typical sounds vs causes: squeal, knock, hiss, hum, etc.
• Difference between mechanical problems (moving parts) and electrical/air leakage problems
💭 Think About
• Which choice is most closely related to a high‑pitched squealing noise from a rotating or rubbing surface?
• For each option, ask yourself: would this more likely cause heat, noise, tripping of protection, or leakage of air?
• Think about what kind of problem would show up as an electrical indicator (meters, overloads) versus an audible mechanical sound.
✅ Before You Answer
• Match a squealing sound with problems involving friction in rotating parts rather than air escaping or current draw.
• Consider how a motor overload would usually first be detected (sound, smell, temperature, or protective devices).
• Recall that leaking unloaders usually produce a different characteristic sound (what does high‑pressure air escaping typically sound like?).