FSM Elektronik GmbH – Development, production, measuring and logistics of sensor technology, pressure transducers, pressure sensor, battery electronic, battery charging technology, charging devices, transformers, transformer switching relays (without start-up peak) and capacitors in Kirchzarten Baden-Württemberg, Germany.

TSRD

The electronic load contactor TSRD is used to switch transformers on the three-phase mains.

It is equipped with the so-called soft starting procedure and allows for activating both three-phase transformers and three single-phase transformers without starting current surge (inrush) in no-load operation or under load. The inrush is avoided and not only limited.

The differentiation is made between the primary switchgears delta and star without Mp (application D) and the switchgear star with Mp (application S). As regards to the application with three single-phase transformers the differentiation is made if the transformers are operated between one phase each and N (application N) or if the transformers are operated between two phases in each case (application L). Both the voltage value of the phases and the phase sequence of the connected three-phase mains are monitored.

Installation

The TSRD is installed simply between mains switch and transformer. However, it can also be used as mains switch without potential separation.

The soft starting procedure of the transformers is implemented by means of thyristors. In order to minimise the losses, the same are bridged by an external bypass contactor after the transformers have been fully activated (contactor required in AC1 class). The TSRD will implement an internal contactor activation control, in order to check the bypass of the thyristors. The bypass contactor is used for deactivation purposes. It is also possible to implement transformers without any load or partially loaded with nominal currents of more than 50A.