The recognition of a polyphase machine (1) connected to a converter (10) is suggested in order to adapt the converter (10) to the connected machine (1) prior to an active productive operation. The following is arranged for. Connecting of the polyphase machine with its several electric phases to the converter (10). Supplying of at least a first and a second test signal from the converter (10) to at least one of the several electric phases of the connected machine. Measuring of at least two causal sequences of the test signals. Evaluating of the measuring result to obtain measuring values (r1, r2) and allocating of these measuring values to a comparison function (60, 50). Comparing of the comparison function with a reference function (60a, 60b, 50a, 50b) which represents one type of a polyphase machine.