🔍 Key Concepts

• Radial shift of the rotor and how that changes clearances between the rotor lands and segments "A" • The function of the spring-loaded segments "A" compared with the separate squealer ring "D" • What happens when metal teeth rub on a rotating shaft at start-up speed (contact area, pressure, and heat)

💭 Think About

• If the rotor moves off-center, which parts in the sketch will make hard metal-to-metal contact first, and along what surfaces? • Look at how the springs are arranged behind segments "A" – do they allow the segments to move freely away from the rotor, or do they tend to keep the teeth close to the machined lands? • Is the squealer ring "D" positioned so it will definitely touch and warn the operator before any other rubbing damage can occur, or only after clearances have already closed up elsewhere?

✅ Before You Answer

• Trace the direction of possible rotor radial movement and identify where clearances would disappear first between the rotor and segments "A". • Decide whether spring compression alone is enough to prevent tooth damage when the rotor shifts, or whether the contact pressure and speed would still be severe. • Ask whether frictional heat and scoring can develop very quickly at start-up when metal teeth rub on the rotor, even over a short period of time.