Raising vacuum on a main turbine unit...

Raising vacuum on a main turbine unit...

Question 1 of 270705eccefa1bacbc34ba4d472da

Raising vacuum on a main turbine unit without using the turning gear will result in __________.

Question 1 of 27070

Q

Raising vacuum on a main turbine unit without using the turning gear will result in __________.

🔍 Key Concepts

• Main steam turbine construction: rotor, casing, and labyrinth packing clearances • Effects of thermal expansion when heating a stationary rotor • Purpose of turning gear during warm-up and vacuum raising

💭 Think About

• What happens to a large rotor and its clearances if you heat the turbine unevenly while it is not slowly turning? • Why is the turning gear used any time you are warming up or pulling vacuum on a main turbine unit? • Which of the choices directly relates to metal-to-metal contact or distortion caused by uneven thermal expansion?

✅ Before You Answer

• Identify which choice is specifically about rotor condition and clearances, not just accessory equipment • Ask yourself which effect would be most serious for turbine internals during warm-up from rest • Confirm which component would be most affected by uneven heating and lack of rotation: the air ejector, the time to raise vacuum, or the rotor and its seals