Abstract: The device comprises inductance coils (6) which are each allocated to one phase and which are wound around a common magnetic core in the same direction and with the same number of windings. One each of the inductance coils (6) is connected to one each of the phase leads (3,5) for supplying the multiphase load (4), the connection being made in series between the converter (1) and the load (4). The load can particularly be a multiphase asynchronous motor.The inductance coils (6) and the magnetic core can be dimensioned equivalent to a power supply transformer adjusted to the frequency and rating of the converter (1), so that deficiencies in the electromagnetic symmetry of the load (4) are balanced, or, on the other hand, they can be dimensioned equivalent to a mains filter adjusted to the frequency and rating of the spikes of converter (1), in order to remove such spikes from the respective phase (3) of the power supply.

Abstract: A device having inductance coils which are each allocated to one phase and which are wound around a common magnetic core in the same direction and with the same number of windings. One of each of the inductance coils is connected to one of each of the phase leads for supplying the multi-phase load, the connection being made in series between the converter and the load. The load can particularly be a multi-phase asynchronous or synchronous motor.

Abstract: The stator current has a variable frequency which is changed by using a predetermined frequency change rate. The resulting effective value of the stator current is compared with the current control variable. If it is greater the frequency is now kept constant. If this corresponds to the setpoint speed the process terminates, if not, the frequency change will start again as soon as the effective value gets smaller than the current control variable. An a.c. voltage mains may operate, accelerate or brake the motor via a rectifier and an inverter, in cases of voltage failure the stator current is switched through to a load resistor. The variation of the speed may follow a steady or a garland-shaped course, from the from and dimension of a festoon element a measure for the "torsional rigidity" may be obtained. By means of shifting between star connection and delta connection the frequency range may be expanded in order to keep the torque essentially the same.