STS Spezial-Transformatoren-Stockach
STS Spezial-Transformatoren-Stockach is a German manufacturer of custom inductive components, founded in 1973 and headquartered in Stockach on Lake Constance, Baden-Württemberg.
STS Spezial-Transformatoren-Stockach GmbH & Co. KG develops and manufactures customised transformers and chokes for industrial, medical, railway and smart grid applications. According to the company, around 190 employees work at its Stockach headquarters.
The product range covers power ratings from 1 kW to 10 MW, voltages up to 60 kV, currents up to 10 kA and frequencies from 1 kHz to 10 MHz.
Rail products
For rail, STS supplies medium-frequency transformers and chokes designed for power-electronic converter systems. These components sit within the power supply and electrification chain on board the vehicle, between the catenary input and the DC link.
The company holds a US patent, granted in 2016, for a liquid-insulated medium-frequency transformer developed for railway converter applications. The patented design addresses the conversion of the European catenary voltages 15 kV 16.7 Hz and 25 kV 50 Hz to DC-link voltages of 1.8–3.6 kV — the same conversion task performed by conventional traction transformers at line frequency.
Medium-frequency designs allow higher power density than line-frequency transformers, which is why they are studied as a lighter alternative in traction chains. STS focuses on the insulation and cooling engineering this requires: its patented design places windings in sealed chambers filled with circulating insulating liquid.
Market position
STS operates as a custom-specification supplier rather than a catalogue manufacturer. Each component is engineered to the customer’s electrical and thermal requirements.
Rail is one of four target markets alongside industry, medical technology and smart grid applications. The company exports worldwide from its single German production site.
Current activity
STS presents at trade fairs and maintains active recruitment for its Stockach site, according to its own channels. The company continues to develop its medium-frequency transformer portfolio for converter-based applications.
