| 摘要 |
<p>The machine speed is controlled by varying the stator current. When the speed is controlled, the asynchronous machine terminal voltage is continuously kept at an approx. constant value. When the stator voltage deviates, it is corrected by changing the rotor slip frequency by changing the stator current frequency faster than the stator current magnitude can change. The stator current frequency change is so small, that the rotor slip frequency remains smaller than the frequency difference between the pull-out point and synchronism point of the torque-rotor frequency characteristic.</p> |
