Abstract: In a ring spinning or ring twisting machine the spindles of which each have an asynchronous motor as drive means, and the auxiliary apparatus thereof are driven by at least one electric motor having variable rotational speed, and the ratio of the rotational speeds of the electric motor driving the auxiliary apparatus and the asynchronous motors remains constant, a reluctance motor is used to drive the auxiliary apparatus. Two converters are used which are controlled in such a manner that the speed ratio remains constant.

Abstract: To regulate the speed of a plurality of asynchronous motors fed by a converter having a variable output frequency and output voltage and having a load-dependent slip, particularly asynchronous motors for driving spindles of a textile machine, the rotational frequency of several selected asynchronous motors is measured by means of respective digital frequency indicators. This measurement takes place in continuous repetition, always beginning simultaneously. The pulses of the frequency indicators are counted by means of respective first counters (1-6), all of which release a pulse when they reach the same counter condition. An OR circuit (13-17) connects the counter outputs with a second pulse counter (18) in such a manner that this condition is reached first by the output pulse released by the highest rotational frequency and then by the output pulses released by the second-highest rotational frequency, etc.