| 摘要 |
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. When the second pulse counter (18) has counted a predetermined number of pulses, the last of which being released by the frequency representing the average speed value, the second pulse counter (18) produces an output pulse which results in all counters (1-6, 18) being reset. The one of the AND gates (25-30) to which the rotational frequency representing the average frequency value is applied is triggered to transmit the frequency signal to the converter.
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