| 摘要 |
<p>The invention relates to a device and a method for estimating the speed of a slip ring asynchronous machine (1). The asynchronous machine (1) comprises a stator (2) having a stator winding, arranged to be fed with three-phase voltage and current in order to generate a varying magnetic flux, and a rotor (3) having a rotor winding in which the magnetic flux is arranged to induce a voltage to create an electromagnetic torque. The device comprises a measuring member (12) arranged to measure the value of the voltage in the rotor winding during at least one time period and a calculating unit (17), which is arranged, by means of the above measured voltage, to calculate a value of the rotor speed.</p> |
