A circuit-breaker must control and protect, in case of faults or malfunctioning, the connected elements of a plant. In order to perform this function, after detection of an anomalous condition, the release intervenes in a definite time by opening the interrupting part. The protection releases fitted with ABB SACE moulded-case and air circuitbreakers can control and protect any plant, from the simplest ones to those with particular requirements, thanks to their wide setting possibilities of both thresholds and tripping times. Among the devices sensitive to overcurrents, the following can be considered: • thermomagnetic releases and magnetic only releases; • microprocessor-based releases; • residual current devices. The choice and adjusting of protection releases are based both on the requirements of the part of plant to be protected, as well as on the coordination with other devices; in general, discriminating factors for the selection are the required threshold, time and curve characteristic.1.3.1 THERMOMAGNETIC RELEASES AND MAGNETIC ONLY RELEASES The thermomagnetic releases use a bimetal and an electromagnet to detect overloads and short-circuits; they are suitable to protect both alternating and direct current networks. A circuit-breaker must control and protect, in case of faults or malfunctioning, the connected elements of a plant. In order to perform this function, after detection of an anomalous condition, the release intervenes in a definite time by opening the interrupting part. The protection releases fitted with ABB SACE moulded-case and air circuitbreakers can control and protect any plant, from the simplest ones to those with particular requirements, thanks to their wide setting possibilities of both thresholds and tripping times. Among the devices sensitive to overcurrents, the following can be considered: • thermomagnetic releases and magnetic only releases; • microprocessor-based releases; • residual current devices. The choice and adjusting of protection releases are based both on the requirements of the part of plant to be protected, as well as on the coordination with other devices; in general, discriminating factors for the selection are the required threshold, time and curve characteristic. The following table shows the types of thermo-magnetic and magnetic only trip units available for SACE Tmax XT and Tmax T circuit-breakers. CBs thermomagnetic releases MF MA TMD TMA TMG XT1 - - - - XT2 XT3 - - XT4 - - Legenda MF Fixed magnetic only releases MA Adjustable magnetic only releases TMG Thermomagnetic release for generator protection TMD Thermomagnetic release with adjustable thermal and fixed magnetic threshold TMA Thermomagnetic release with adjustable thermal and magnetic threshold

断路器必须在发生故障或故障时控制和保护设备的连接元件。为了执行此功能，在检测到异常情况后，释放装置通过打开中断部件在一定时间内进行干预。配备ABB SACE模制外壳和空气断路器的保护脱扣器可以控制和保护任何设备，从简单的设备到有特殊要求的设备，这得益于其阈值和跳闸时间的广泛设置可能性。在对过电流敏感的设备中，可以考虑以下情况：•热磁释放和纯磁释放；•基于微处理器的版本剩余电流装置。保护脱扣器的选择和调整既基于待保护装置部分的要求，也基于与其他装置的协调；一般来说，选择的判别因素是所需的阈值、时间和曲线特征。1.3.1热磁脱扣器和仅磁脱扣器热磁脱扣器使用双金属和电磁铁检测过载和短路；它们适用于保护交流和直流网络。断路器必须在发生故障或故障时控制和保护设备的连接元件。为了执行此功能，在检测到异常情况后，释放装置通过打开中断部件在一定时间内进行干预。配备ABB SACE模制外壳和空气断路器的保护脱扣器可以控制和保护任何设备，从简单的设备到有特殊要求的设备，这得益于其阈值和跳闸时间的广泛设置可能性。在对过电流敏感的设备中，可以考虑以下情况：•热磁释放和纯磁释放；•基于微处理器的版本剩余电流装置。保护脱扣器的选择和调整既基于待保护装置部分的要求，也基于与其他装置的协调；一般来说，选择的判别因素是所需的阈值、时间和曲线特征。下表显示了SACE Tmax XT和Tmax T断路器可用的热磁和纯磁跳闸装置的类型。CBs热磁脱扣器MF MA TMD TMA TMG XT1--XT2 XT3--XT4--Legenda MF固定磁脱扣器MA可调磁脱扣器TMG热磁脱扣器用于发电机保护TMD热磁脱扣器具有可调热阈值和固定磁阈值TMA热磁脱扣器具有可调热阈值和磁阈值