Cranes – Design, Practice, and Maintenance phần 5 ppsx

Cranes – Design, Practice, and Maintenance120 4. Lowering speed of the load: û (m͞min) ûG60 m͞min 5. Wire rope speed on the drum: û d G2 · û (m͞min) û d G2 · 60G120 m͞min G(2 · û) : 60 (m͞sec) G120 :60 G2m͞sec 6. Nos. of rev͞min of the drum: n d Gû d :( π · D d ) (rev͞min) n d G120 : ( π · 1,2) G31,84 rev͞min 7. Nos. of rev͞min of the motor: n motor Gn d · i gb (rev͞min) n m G31,84 · 24,6 G783 rev͞min 8. Inertia moment on the motorshaft from: motor(s); brakesheave(s) and gearbox: J rot GJ m CJ b CJ gb (kg m 2 ) J rot G24C16C6 G46 kg m 2 9. Reduced inertia moment on the motorshaft from the weight of the spreader plus load: J L G(L · û 2 d · η gb ): ω 2 1 (kg m 2 ) J L G(31 350 · 2 2 · 0,94): ΂ 783 · 2 · π 60 ΃ 2 J L G117 876 :81,95 2 G17,55 kg m 2 10. J total GJ rot CJ L (kg m 2 ) J tot G46C17,55 G63,55 kg m 2 Brakes 121 11. After pushing the emergency button, the load is accelerated by M 1 during ∆t sec (activating time for the brake) with ∆ ω 2 (rad͞sec): ∆ ω 2 G ∆t · M 2 J rot (rad͞sec) ∆ ω 2 G (0,3 · 7051) 46 G46 rad͞sec 12. The activated brake starts mechanical braking after ∆t sec with a rotational speed on the motorshaft of: ω 3 G( ω 1 C ω 2 )(rad͞sec) ω 3 G ΂ 783 · 2 π 60 ΃ C46 ω 1 G(n m :60) · 2 π (rad͞sec) G81,95C46 G127,95 rad͞sec 13. The numbers of rev͞min of the motor- and brake-shaft is then: n 2 G ω 3 · 60 2 π (rev͞min) n 2 G128 · 60 2 π G1223 rev͞min 14. The wire rope speed on the drum is then: û d2 G n 2 n m · û d (m͞sec) û d2 G 1223 783 · 2 G3,123 m͞sec 15. The effective brake moment is: M be G η b · M b (Nm) M be G0,95 · 19 000 G18 050 Nm 16. The effective braking time is: t brake G ω 3 · J total M be AM 1 (sec) t br G 128 · 63,55 18 050A7051 G0,740 sec 17. Total braking time: tG(∆tCt br ) (sec) tG0,3C0,74G1,04 sec Cranes – Design, Practice, and Maintenance122 18. Wire rope displacement on the drum during braking: S d G∆S 1 C∆S 2 (m) ∆S 1 Gdisplacement on the drum during ∆t (m) ∆S 2 Gdisplacement on the drum during deceleration whilst braking in t br sec. ∆S 1 G û d Cû d2 2 · ∆t (m) ∆S 1 G 2C3,123 2 · 0,3 G0,768 m ∆S 2 G 3,123 2 · 0,74 G1,155 m ∆S 2 G û d2 2 · t br (m) S d G0,768C1,155G1,923 m 19. Total displacement of spreader and load during emergency stop: in lowering direction (see Fig. 4.2.2) S sprCL GS d :2 (m) S sprCL G1,923 :2 G0,96 m Note: – The winch has: 2 motors; 2 brakes; 1 gearbox; 2 drums. – The spreader and the load are suspended by eight ropefalls; 4 of which are fixed on the boom end; the other 4 falls run via wire rope sheaves to the 2 wire rope drums. – ∆t can be taken as ∆tG0,3 sec the worst case for ∆tG0,5 sec. – The maximal peripherical speed of the brake disc must be controlled. The allowed number of brake cycles in an emergency stop can be calcu- lated as follows: Dissipated energy per brake cycle: WBGM br · n 2 9,55 · t br 2000 (kJ) Brakes 123 Fig. 4.2.2 Lowering: emergency stop Nos. of kWh per brake cycle: kWhG kJ 3593 (kWh) Allowed numbers of emergency ZG û B · 2 kWh · 30 (nos) brake cycles; approximately: where û B G98 100 mm 3 for SB23 brakes (for a certain brakepad material) û B G244 800 mm 3 for SB28 brakes (for a certain brakepad material) 30Gbrakepad wear per kWh. The maximum circumference speed of the brake disc which is allowed is: ûG85 m͞sec for a brake disc of Fe52.3 (S 355 J2 G3). 4.3 Hoisting brakes Lowering the load; braking by full motor torque The crane driver is lowering the load and wants to halt the load by stopping the winch by ‘electric braking’. The full motor torque is to be Cranes – Design, Practice, and Maintenance124 Fig. 4.3.1 Wire rope scheme taken as the brake moment. The reeving scheme in Fig. 4.3.1 is assumed for a container crane. Example 1. Weight of spreader plus Load: Q (kg) QG66 000 kg 2. Force on the wire ropes on the drum: L (kg) (see Fig. 4.3.1) LG(Q :2)· η s (kg) LG(66 000 :2) · 0,95 G31 350 kg η s G η sheavesCdrum Gn · 0,99 (nG5) 3. Torque on motorshaft: M 1 G ΂ L · D drum 2 : i gb ΃ · η gb M 1 G ΂ 31 350 · 1,2 2 :24,6 ΃ · 9,81 (Nm) · 0,94 · 9,81 G7051 Nm Drum diam. D drum G1,2 m Gearbox reduction i gb G24,6 Efficiency gearbox η gb G0,98 3 Brakes 125 4. Lowering speed of the load: û (m͞min) ûG60 m͞min 5. Wire rope speed on the drum: û d G2 · û (m͞min) û d G2 · 60G120 m͞min G(2 · û): 60 (m͞sec) G120 : 60 G2m͞sec 6. Nos. of rev͞min of the drum: n d Gû d :( π · D d ) (rev͞min) n d G120 :( π · 1,2) G31,84 rev͞min 7. Nos. of rev͞min of the motor: n motor Gn d · i gb (rev͞min) n m G31,84 · 24,6 G783 rev͞min 8. Inertia moment on the motorshaft from: Motor(s); brake sheave(s) and gearbox: J rot GJ m CJ b CJ gb (kg m 2 ) J rot G24C16C6 G46 kg m 2 9. Reduced inertia moment on the motorshaft from the weight of the spreader plus load: J L G(L · û 2 d · η gb ): ω 2 1 (kg m 2 ) J L G(31 350 · 2 2 · 0,94) : ΂ 783,2 π 60 ΃ 2 J L G117 876 :81,95 2 G17,55 kg m 2 10. J total GJ rot CJ L (kg m 2 ) J tot G46C17,55 G63,55 kg m 2 Cranes – Design, Practice, and Maintenance126 11. Braking is immediately started with the electric current, delivering the nominal motor torque. (The 2 motors deliver in total NG720 kW at nG783 rev͞min) M nom G N · 9550 n (Nm) M nom G 720 · 9550 783 M nom GM el.braking torque M nom GM eb G8781 Nm 12. ω mot G n 60 · 2 π (rad͞sec) ω mot G 783 60 · 2 π (rad͞sec) G81,95 rad͞sec 13. The effective braking time is: t brake G ω mot · J total M eb AM 1 (sec) t br G 81,95 · 63,55 8781A7051 secG3 sec Fig. 4.3.2 Lowering: electrical braking by full motor torque Brakes 127 14. Wire rope displacement on the drum during braking: S d G 1 2 · û d · t br (m) S d G 1 2 · 2 · 3 G3m 15. Total displacement of spreader and load during electric braking in hoisting direction: S sprCL GS d :2 (m) S sprCL G3:2G1,5 m 4.4 Hoisting brakes Hoisting the load; braking by full motor torque The crane driver is hoisting the load and wants to stop the load by stopping the hoisting winch by ‘electric braking’. We take now the full motor torque as brake moment. Consider a container crane with the reeving shown in Fig. 4.4.1 (schematic). Example 1. Weight of spreader plus load: Q (kg) QG66 000 kg 2. Force on the wire ropes on the drum: L (kg) (see Fig. 4.4.1) LG(Q :2) · η s (kg) LG(66 000 :2) · 0,95 G31 350 kg η s G η sheavesCdrum Gn · 0,99 (nG5) Fig. 4.4.1 Cranes – Design, Practice, and Maintenance128 3. Torque on motorshaft: M 1 G ΂ L · D drum 2 : i gb ΃ · η gb M 1 G ΂ 31 350 · 1,2 2 :24,6 ΃ · 9,81 (Nm) · 0,94 · 9,81 G7051 Nm Drum diam. D drum G1,2 m Gearbox reduction i gb G24,6 Efficiency gearbox η gb G0,98 3 4. Hoisting speed of the load: û (m͞min) ûG60 m͞min 5. Wire rope speed on the drum: û d G2 · û (m͞min) û d G2:60G120 m͞min G(2 · û) : 60 (m͞sec) G120 :60G2m͞sec 6. Nos. of rev͞min of the drum: n d Gû d :( π :D d ) (rev͞min) n d G120 : ( π · 1,2) G31,84 rev͞min 7. Nos. of rev͞min of the motor: n motor Gn dr · i gb (rev͞min) n m G31,84 · 24,6 G783 rev͞min 8. Inertia moment on motorshaft from: motor(s); brake sheave(s) and gearbox: J rot GJ m CJ b CJ gb (kg m 2 ) J rot G24C16C6 G46 kg m 2 9. Reduced inertia moment on the motorshaft from the weight of the spreader plus load: J L G(L · ν 2 d · η gb ): ω 2 1 (kg m 2 ) J L G(31 350 · 2 2 · 0,94): ΂ 783,2 π 60 ΃ 2 J L G117 876 :81,95 2 G17,55 kg m 2 Brakes 129 10. J total GJ rot CJ L (kg m 2 ) J tot G46C17,55 G63,55 kg m 2 11. Braking is immediately started with the electric current, delivering the nominal motor torque. (The 2 motors deliver in total NG720 kW at nG783 rev͞min) M nom G N · 9550 n (Nm) M nom G 720 · 9550 783 M nom GM el.braking torque M nom GM eb G8781 Nm 12. ω mot G n 60 · 2 π (rad͞sec) ω mot G 783 60 · 2 π (rad͞sec) G81,95 rad͞sec 13. The effective braking time is: t brake G ω mot · J total M eb CM 1 (sec) t br G 81,95 · 63,55 8781C7051 sec G0,329 sec 14. Wire rope displacement on the drum during braking: S d G 1 2 · û d · t br (m) S d G 1 2 · 2 · 0,329 G0,329 m 15. Total displacement of spreader and load during electric braking in hoisting direction: S sprCL GS d :2 (m) S sprCL G0,329 : 2 G0,165 m [...]... travelling cranes and portal bridge cranes Standards 151 ISO 8087: 19 85 Mobile cranes – Drum and sheave sizes ISO 8306: 19 85 Cranes – Overhead travelling cranes and portal bridge cranes – Tolerances for cranes and tracks ISO 856 6-1: 1992 Cranes – Cabins – Part 1: General ISO 856 6-2: 19 95 Cranes – Cabins – Part 2: Mobile cranes ISO 856 6-3: 1992 Cranes – Cabins – Part 3: Tower cranes ISO 856 6-4: 1998 Cranes –. .. appliances – Control – Layout and characteristics – Part 2: Basic arrangement and requirements for mobile cranes ISO 7 752 -2: 19 85 Add 1: 1986 ISO 7 752 -3: 1993 Cranes – Control – Layout and characteristics – Part 3: Tower cranes ISO 7 752 -4: 1989 Cranes – Controls – Layout and characteristics – Part 4: Jib cranes ISO 7 752 -5: 19 85 Lifting appliances – Controls – Layout and characteristics – Part 5: Overhead... devices – Part 1: General ISO 102 45- 2: 1994 Cranes – Limiting and indicating devices – Part 2: Mobile cranes ISO 102 45- 3: 1999 Cranes – Limiting and indicating devices – Part 3: Tower cranes ISO 102 45- 5: 19 95 Cranes – Limiting and indicating devices – Part 5: Overhead travelling and portal bridge cranes Cranes – Requirements for mechanisms – Part 1: General ISO 10972-1: 1998 ISO 10973: 19 95 Cranes – Spare... 9926-1: 1990 Cranes – Training of drivers – Part 1: General ISO 9927-1: 1994 Cranes – Inspections – Part 1: General ISO 9928-1: 1990 Cranes – Crane driving manual – Part 1: General ISO 9942-1: 1994 Cranes – Information labels – Part 1: General ISO 9942-3: 1999 Cranes – Information labels – Part 3: Tower cranes 152 Cranes – Design, Practice, and Maintenance ISO 102 45- 1: 1994 Cranes – Limiting and indicating... 1997 Cranes – Measurement of wheel alignment ISO 11660-1: 1999 Cranes – Access, guards and restraints – Part 1: General ISO 11660-2: 1994 Cranes – Access, guards and restraints – Part 2: Mobile cranes ISO 11660-3: 1999 Cranes – Access, guards and restraints – Part 3: Tower cranes ISO 11660 -5: 2001 Cranes – Access, guards and restraints – Part 5: Bridge and gantry cranes ISO 11661: 1998 Mobile cranes –. .. – Cabins – Part 4: Jib cranes ISO 856 6 -5: 1992 Cranes – Cabins – Part 5: Overhead travelling and portal bridge cranes ISO 8686-1: 1989 Cranes – Design principles for loads and load combinations – Part 1: General ISO 8686-3: 1998 Cranes – Design principles for loads and load combinations – Part 3: Tower cranes ISO 8686 -5: 1992 Cranes – Design principles for loads and load combinations – Part 5: Overhead... 1998͞Cor 1: 2000 ISO 12478-1: 1997 Cranes – Maintenance manual – Part 1: General ISO 12480-1: 1997 Cranes – Safe use – Part 1: General Standards 153 ISO 12482-1: 19 95 Cranes – Condition monitoring – Part 1: General ISO 124 85: 1998 Tower cranes – Stability requirements ISO 13200: 19 95 Cranes – Safety signs and hazard pictorials – General principles ISO 155 13: 2000 Cranes – Competency requirements for crane... 4306-1: 1990 Cranes – Vocabulary – Part 1: General ISO 4306-2: 1994 Cranes – Vocabulary – Part 2: Mobile cranes ISO 4306-3: 1991 Cranes – Vocabulary – Part 3: Tower cranes ISO 4310: 1981 Cranes – Test code and procedures ISO 7296-1: 1991 Cranes – Graphic symbols – Part 1: General ISO 7296-1: 1991͞Amd 1: 1996 ISO 7296-2: 1996 Cranes – Graphical symbols – Part 2: Mobile cranes ISO 7 752 -2: 19 85 Lifting appliances... Cranes – Classification – Part 3: Tower crane ISO 4301-4: 1989 Cranes and related equipment – Classification – Part 4: Jib cranes ISO 4301 -5: 1991 Cranes – Classification – Part 5: Overhead travelling and portal bridge cranes ISO 4302: 1981 Cranes – Wind load assessment ISO 4304: 1987 Cranes other than mobile and floating cranes – General requirements for stability ISO 43 05: 1991 Mobile cranes – Determination... 13 155 Cranes Safety Non-fixed load lifting attachments prEN 13 157 Cranes Safety Hand powered cranes prEN 1 355 7 Cranes Controls and control stations prEN 1 358 6 Cranes Access prEN 13 852 -1 Cranes Offshore cranes Part 1 General purpose offshore cranes prEN 14238 Cranes Manually controlled load manipulating devices 5. 2 FEM ´ The Federation Europeen de la Manutention has published a number of well known standards . m 2 ) J L G(31 350 · 2 2 · 0,94) : ΂ 783,2 π 60 ΃ 2 J L G117 876 :81, 95 2 G17 ,55 kg m 2 10. J total GJ rot CJ L (kg m 2 ) J tot G46C17 ,55 G63 ,55 kg m 2 Cranes – Design, Practice, and Maintenance1 26 11 M be G0, 95 · 19 000 M be G0, 95 · 19 000 G18 050 Nm G18 050 Nm Cranes – Design, Practice, and Maintenance1 36 16. The effective braking time is: t brake G ω 3 · J total M be AM 1 (sec) t br G 128 · 63 ,55 18. · 0, 95 G31 350 kg η s G η sheavesCdrum Gn · 0,99 (nG5) Fig. 4.4.1 Cranes – Design, Practice, and Maintenance1 28 3. Torque on motorshaft: M 1 G ΂ L · D drum 2 : i gb ΃ · η gb M 1 G ΂ 31 350 · 1,2 2 :24,6 ΃ ·