| 摘要 |
The present invention relates to a method of determining a speed of rotation of a squirrel-cage motor, wherein samples from the current taken by the squirrel-cage motor are collected by an electric current measuring device at a predetermined sampling frequency for a measurement period, the samples being stored as measurement data of a fixed format. The method is characterized by comprising the step of determining the rotation speed of the squirrel-cage motor from the measurement data by determining the base frequency and side frequencies of the electric current taken by the squirrel-cage motor, the rotation speed frequency of the squirrel-cage motor being obtained by subtracting the lower side frequency from the higher side frequency and by dividing the difference thus obtained by two. |
