| 摘要 |
PURPOSE:To perform a stable control by switching an inverter control command generator when a slip frequency once becomes negative while an elevator elevates at the prescribed speed, and forcibly performing the regenerative control during this switching. CONSTITUTION:Contactors 18a, 18b are shifted to a contact (a) side at starting time, an elevator is accelerated while a slip frequency command signal 14a is positive, a switching unit 18c is operated when the signal 14a becomes nega tive during the prescribed elevating to shift the contactors 18a, 18b to a contact (b) side. Then, it is shifted to positive side by the variation in the speed signal 11a during elevating near zero of the signal 14a, but if it is once switched to the second inverter control command during the prescribed elevating, the unit 18c does not operate during the period, thereby keeping the regenerative state as it is. |
