| 摘要 |
The by-pass circuit, comprising an auxiliary transformer (8), circuit breaker (7) and variable frequency static converter (6), derives a supply from the grid transformer (5) which it applies to the generator (1), in motor configuration, to start the turbine and run it up to speed. This circuit is teed off the grid transformer/generator circuit-breaker (3A) connection and feeds the generator through a 3-position isolator (4) whose moving contact arm (4F) has one end pivoted at a point (4E) on the generator/main circuit-breaker connection. In normal operational service, the arm's free end is isolated (4B); during starting it connects (4A) with the by-pass circuit, the main circuit-breaker remaining open (3B). In the third position (4C) it applies an earth (4G) to the gearbox/main circuit-breaker connection to give safe maintenance access.
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