| 摘要 |
<p>1532902 Elevator speed control HITACHI Ltd 6 May 1976 [9 May 1975] 18640/76 Heading G3N An elevator control system using an A.C. induction motor 6 has open loop motor speed control during acceleration of car 1 and closed loop control during deceleration in dependence on the difference between car commanded and actual speeds. The three phase induction motor 6 is connected via tachometer 7 and electromagnetic brake 5 to the car sheave 4, and to the three phase A.C. power supply 8 via contactors 9-1, 9-2, 9-3, 13-1, 13-2. For car acceleration, the contactors 9 are closed and contactors 13 are open which gives a circuit configuration as shown on Fig. 2a. For car deceleration the contactors 9 are open and contactors 13 are closed giving D.C. control using the circuit configuration shown in Fig. 2b. The desired speed pattern is generated by unit 16 (described in detail), Fig. 6 (not shown) and compared with actual speed in unit 17. The difference passes via contact 13-13a to phase shifter 18 described in detail, Figs. 7 and 8 (not shown). The acceleration command is applied directly through contact 13-3b. In addition to single phase control, two or three phase control is possible Figs. 9 and 10 (not shown).</p> |
