| 摘要 |
A compressed-gas power circuit breaker (1) has a density monitor (3) for monitoring the density of the extinguishing gas which is located in the extinguishing chamber, which density monitor (3) initiates a warning (4) against carrying out switching operations, or blocking (5) of the drive device (2) in the event of the density falling below limiting values. An additional pressure monitor (7) is provided for detecting a minimum gas pressure in the extinguishing chamber, in conjunction with a temperature-dependent switch (8) which is used for making the pressure monitor (7) effective instead of the density monitor (3). In consequence, the operating range of the power circuit breaker (1) is extended in the direction of extremely low environmental temperatures. <IMAGE>
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