Transformer contact switch Type selection
Transformer switching relay, TSR, is the generic term. There are five different types of TSR, TSRL, TSRLF, TSR01, TSRD and TSRDF. Three are explained in more detail here. You can find out more about TSRLF and TSR01 from FSM AG . There are numerous variants of each type, which can be determined by the area of use and application. They can also be distinguished by the special number.
The TSRL or TSRLF can be used for single-phase transformers.
The TSRLF is best suited for heating via a transformer, where frequent switching is required.
Two TSRLs up to 32A are also suitable for three-phase transformers, also known as three-phase transformers, which consist of the interconnection of three single-phase transformers, these are referred to as non-genuine three-phase transformers. For higher outputs, two TSRLF control modules are suitable, which control two-torque switching solid state relays, with or without bypass contactor bridging.
For real three-phase transformers, those with the coils on a common three-legged core, two TSRLs can also be used up to a size of 10 kVA. TSRDFs are suitable for larger genuine three-phase transformers.
The inductive premagnetizing principle developed by Emeko is used for switching large transformers, i.e. larger than 100 kVA, even in the medium voltage range.
See also three-phase transformers, switching on large transformers via premagnetization. Various transformer manufacturers, such as Riedel, Trafo-Schneider-March and Tauscher, supply the pre-magnetizing devices or the complete soft switch.
TSRL
The TSRL uses a soft inrush current method to not only limit the inrush current but also to prevent it directly.
One or more single-phase transformers can be switched on both in no-load operation and under load without inrush current.
TSRD
The TSRD is suitable for switching on three-phase transformers with rated currents of up to 50A. To be able to use the TSRD, an external baypass contactor must be used to bridge the internal actuators.
TSRDF
The TSRDF module enables the control of solid state relays or thyristor modules as well as a bypass contactor for three-phase transformers. It can be used to build transformer switching relays for up to 500A and more and also to clock transformers with pulse groups. This saves an expensive thyristor controller.