Circuit breakers for transformer protection

Fuseless protection on the primary side

Circuit breakers for transformer protection are specially designed for fuse less protection of control transformers on the primary side against overloads and short-circuits. In addition, the device allows manual connection and disconnection of the transformer from the mains. 

Line protection and disconnect system is required on the primary side. Winding fault can only be protected on the primary side.  Transformers generate at the start-up very high current peak (inrush current) of 8-20 times the nominal current, for this reason, regular protection cannot be used. In these applications where transformers must be appropriately protected, ABB’s new MS132-T is an excellent solution.

MS132-T is a 45 mm (width) compact and powerful range up to 25 A. This type has also a clear and reliable indication of fault in a separate window in the event of short-circuit tripping. Further features are the build-in disconnect function, temperature compensation, trip-free mechanism and a rotary handle with a clear switch position indication. The handle is lockable to protect against unauthorized changes. 

Auxiliary contacts, signaling contacts, undervoltage releases, shunt trips, power in-feed blocks are available as accessory. These are suitable for the complete MS116/MS132/MS165-range. Moreover ABB offers special accessories for fast single phase setup.

Main benefits
• Space saving and cost efficient protection of control transformers
• Protection and disconnect function in one device on the primary side
• Separate magnetic trip indication window
• Possible use of existing MS116/132 accessories 
• Special accessories for fast single phase setup
• Established and proven technology

Main features
• Disconnect function, overload and short circuit protection in one compact device
• Transformer windings short-circuit protection on the primary side
• Temperature compensation
• Rotary handle with clear trip indication



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