The invention relates to a device for testing transformers, having a static frequency converter (2). The static frequency converter (2) comprises a plurality of outlets (21, 22, 23), which are connected to a filter device (6). The filter device (6) also comprises a plurality of outlets (31, 32, 33), which are connected to a matching transformer (8), and wherein the matching transformer (8) is connected to the transformer (15) intended for testing. The filter device (6) is a filter transformer (11).