| 摘要 |
PURPOSE:To suppress the production of an abrupt brake torque at the initial time of deceleration by switching the reference frequency of a thrust load brake controller in response to the compared result of the speed of a wound-rotor type induction motor with synchronizing speed. CONSTITUTION:At winding up and down starting times, a starting time interlock 27 applies a signal of a high frequency reference setter 31 to a variable voltage and variable frequency power source 16 through a reference converter 22 and an acceleration/deceleration rate circuit 30. Thus, the brake force of the thrust load brake is gradually released. Then, at the decelerating time of winding up, a signal that a motor 3 rotates at the speed lower than the synchronizing speed is outputted from a comparator 23, and a deceleration time interlock 26 outputs a signal of a frequency reference setter 31. At the deceleration time of winding down, a signal that the motor 3 is rotated at the speed higher than the synchronizing speed is outputted from the comparator 23, and a deceleration interlock 26 outputs a signal of a low frequency reference setter 24. |
