Chương 6 Hiện tượng võng xuống và Tát của dây cáp, Rock and Roll của Spreader; Xe đẩy Máy móc so với Wire Rope Xe đẩy; Twin-thang máy, định vị, thiết bị nhận dạng tự động (AEI) Hiện tượng võng xuống và tát của dây cáp, Palăng hệ thống dây cáp cần cẩu quay cho container và lấy unloaders | 120 Cranes-Design Practice and Maintenance 4. Lowering speed of the load V m min V 60 m min 5. Wire rope speed on the drum Vd 2 V m min Vd 2 60 120 m min 2 v 60 m sec 120 60 2m sec 6. Nos. of rev min of the drum nd vd n Dd rev min nd 120 n 1 2 31 84 rev min 7. Nos. of rev min of the motor nmotor nd igb rev min nm 31 84 24 6 783 rev min 8. Inertia moment on the motorshaft from motor s brakesheave s and gearbox Jrot Jm Jb Jgb kg m2 Jrot 24 16 6 46 kg m2 9. Reduced inertia moment on the motorshaft from the weight of the spreader plus load Jl L vd ngb 2 kgm2 Jl 31 350 22 0 94 783 2 n 60 Jl 117 876 81 952 17 55 kg m2 10. Jtotal Jrot Jl kg m2 Jtot 46 17 55 63 55 kg m2 Brakes 121 11. After pushing the emergency button the load is accelerated by M1 during At sec activating time for the brake with Arn2 rad sec Am2 rad sec Jrot A 0 3 7051 46rad sec 46 12. The activated brake starts mechanical braking after At sec with a rotational speed on the motorshaft of 0 3 m1 w2 rad sec 1 nm 60 2n rad sec a - n 1 46 60 81 95 46 127 95 rad sec 13. The numbers of rev min of the motor- and brake-shaft is then n2 0 3 rev min 2n 60 n2 128 1223 rev min 14. The wire rope speed on the drum is then Vd2 Vd m sec nm 1223 . . Vd2 2 3 123 m sec 783 15. The effective brake moment is Mbe nb Mb Nm Mbe 0 95 19 000 18 050Nm 16. The effective braking time is t J . _ 128 63 55 tbrake sec tbr _ 0 740 sec Mbe-Mi 18050-7051 17. Total braking time t At tbr sec t 0 3 0 74 1 04 sec 122 Cranes-Design Practice and Maintenance AS1 2 3 123 0 3 0 768 m 2 AS2 3123 0 74 1 155 m 2 2 Sd 0 768 1 155 1 923 m Sspr L 1 923 2 0 96m 18. Wire rope displacement on the drum during braking Sd AS1 AS2 m AS1 displacement on the drum during At m AS2 displacement on the drum during deceleration whilst braking in tbr sec. AC _ Vd Vd2 . . . AS1 - At m AS2 2 tbr m 19. Total displacement of spreader and load during emergency stop in lowering direction see Fig. Sspr L Sd 2 m Note - The winch has 2 motors 2 brakes 1 gearbox 2 drums. -
