Our electronic relays allow for switching transformers and capacitors without any surges.


The TSRL is our standard product for switching of various single–phase transformers. With its soft starting procedure, the relay activates one or several single-phase transformers in no-load operation or under load without inrush.

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The TSRLF is a control unit for an external control element to arrange a transformer switching relay. It is usable for fast switsching and to switch single-phase transformer with high power. External thyristors or semiconductor relays are used as control elements. 

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The TSR01 is a electronic relay to switching of various single-phase-transformers. It switches one or more single phase transformers, in no-load-state or loaded state without inrush current. With our soft starting procedure the inrush current is avoided, not only reduced. 

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The TSRD is our standard product for switching of various three-phase transformers. For example for isolating transformers in special-purpose vehicles with rated current up to 50 A. For operation of the TSRD an external bypass contactor is needed. 

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The TSRDF is a control module, which can be used as a control element of a transformer switching relay when it is used in combination with external thyristors or semiconductor relays in a three-phase current supply. 

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Transformer switching relais from FSM AG are used in industrial sector, medical engineering, traffic and railway engineering, special-purpose vehicles, switchgears, electric heaters (chairlift), lighting technology,  broadcast technology and research. Additionally they can be used for any type of transformer. Transformer switching relays ensure your devices comply with the latest EMV regulations and standards for medical devices. We work together with multiple manufacturers of transformers to provide the best solutions possible.

Lighting technology

Medical devices,
e.g. dialysis machines

Special vehicles,
e.g. for broadcasting 



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