A German customer successfully tested a classical 3-phase 270 A ECO-design welding transformer
with a matching inductor, both developed by Elma TT, and confirmed that efficiency of 85 % (as
required by the Regulation 2019/1784) was achieved. The transformer’s secondary side is wound
with aluminium wire, and so is wound the inductor.
Elma TT started the activities on optimising transformers and inductors for welding equipment in
early 2019 – shortly after the first draft of the Regulation (EU) 2019/1784 was published. The
development was conducted in tight cooperation with our Slovenian partner and customer Iskra
Varjenje. A series of transformers of different powers were developed and tested along with
different inductors. The transformers and inductors were wound with both, copper and aluminium
wires. During this optimizing process the whole chain has to be considered and each link of the chain
has to be optimized individually: transformer, inductor, rectifier, contacts, cables…
The main goal of this optimizing process is the increase of the welding machine efficiency which
means lower energy consumption. The side effect of this process is higher duty cycle of the machine.
At the moment we are developing new welding transformers for various German customers.
The EU Regulation can be found on the following link: https://eur-lex.europa.eu/legal-
The Kärcher Group is our long-standing customer. We supply them with up to 100,000 transformers per year at several production sites. The Kärcher Group evaluates suppliers quarterly and informs us about KPIs (key performance indicators). As a result, we have achieved 0 DPPM (Defect Parts Per Million) for several years in a row.
In order to improve the presentation of our company and the communication with our customers and potential prospects, we have set up a new interactive website.