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Circuit arrangement for testing cross-sectional and quality changes in bodies of magnetizable material. It is known that magnetic properties of iron and rods are related to their mechanical and metallurgical peculiarities. There are therefore special investigators have been proposed for the magnetic-mechanical investigation of bodies of iron, steel or other magnetizable materials whose particular shapes in a long extension should have consistent cross-sections, such as wires, wire ropes, rods, support u. like. Surrounding these bodies with coils to excite an alternating magnetic field in them and with induction coils and comparing the electromagnetic characteristics of these coils by supplying the coils with alternating current of suitable frequency.

In these measurements, the circumstance often makes disturbing that, in order to achieve useful measurements, the measuring apparatus itself must bring close to the body to be examined.

Otherwise one often receives very long connecting lines from the wound around the lanb elongated body coils to the measuring device, in particular, if one z. B. examines a hoisting rope and sets up the Meßapparatin the machine house next to the carrier, and thereby receive the electromagnetic properties of the connecting wires an over ¬ viegenden influence on the electromagnetic properties of the coils wrapped around the rope, if you do not finit very many turns provides. However, the number of turns of these coils is suitably chosen as low as possible, so that the coils can be wound around the ropes quickly in the practical application of the relevant method, since it is not generally possible in practice, hindurchzustecken the ropes through the finished wound coils.

Uni to avoid this evil, the following circuit is proposed here, the accompanying figure is an example of how to use in a simple case of the circuit in such measurement method, the means proposed here against the mentioned disturbing influences of the transmission line. Let i be a rope to be examined, 2 and 3 are the coils that are wrapped around the rope. Instead of now that the leads to these coils 2 and 3 are brought directly to the Meßv device, "-elche from the AC resistors. 4 and 5, the alternator 6 and the measuring instrument 7 is in a known Wheatstonesehen bridge arrangement, according to the present invention, the current of 2 or 3, first in the existing of a few thick turns primary winding of the transformers 8 and 9, from which a much higher number Turned secondary coils then the current in the lines io and ii exceeds. In the transformers 1.2 and 13, which are placed in the vicinity of the receiving device. Then, the so highly biased in 8 and 9 alternating current is reduced again in low-voltage current and enters from there into the above-mentioned measuring device, for example.

Of course you can omit the transformers z2 and 13, if you choose the AC resistors 4 and 5 correspondingly large. However, since in many cases a very simple arrangement is obtained by allowing the resistors 4 and 5 to be directly formed by a drawn-out wire on which a displaceable branch to the measuring instrument 7 is provided, it is often advantageous to apply the voltage the outer end of the resistors 4 and 5 to have as small as possible. By suitable choice of the ratios of the transformers 8, 9, 12 and 13, this arrangement can be adapted to any distance between the magnetizable, elongated body to be measured and the measuring apparatus on the one hand and the selected for other reasons peculiarity of the measuring device 4, 5, 6, 7.

Since the coils 2 and 3 can not be ready-wound ready for rapid execution of the 'measurements on the in-use wire ropes, but the coils must re-wrap each time around the endlessly assumed rope, it is important that the number of turns of the Coil is as low as possible. In the circuit proposed here, one can already manage with a very small number of turns by the corresponding primary windings of the transformers 8 and 9 the winding surfaces, ie the number of turns multiplied by its cross section, the coils 2 and 3 adapts. The most favorable ratio will often be the one in which the number of turns of the coils 2 or 3 multiplied by the iron cross section of the elongated body to be examined i is equal to or nearly equal to the product of number of turns multiplied by the iron cross section of the primary winding of the transformers 8 or 9 ,