HV Exit Exam • Set 6 Question 19 of 30
In a modern Vacuum Circuit Breaker (VCB), the vacuum pressure maintained inside the sealed interrupter bottle is in the order of:
✓
Direct Answer
Option D: 10⁻⁶ to 10⁻⁹ Torr (approx. 10⁻⁴ to 10⁻⁷ Pa)
Vacuum interrupters are sealed under ultra-high vacuum of 10⁻⁴ to 10⁻⁷ Pa (10⁻⁶ to 10⁻⁹ mmHg/Torr) where the mean free path of electrons exceeds the contact gap distance.
All Options
A
10 mm Hg
B
10⁻² mm Hg
C
10⁻⁶ mm Hg
D
10⁻⁶ to 10⁻⁹ Torr (approx. 10⁻⁴ to 10⁻⁷ Pa)
(Correct Answer)
Detailed Explanation & Context
Vacuum interrupters are sealed under ultra-high vacuum of 10⁻⁴ to 10⁻⁷ Pa (10⁻⁶ to 10⁻⁹ mmHg/Torr) where the mean free path of electrons exceeds the contact gap distance.
Relevant Framework: STCW 2010 Manila Amendments • DG Shipping E-Learning & Exit Exam Standards • High Voltage Safety Officer & Switchgear Operations (HV).
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