Diesel-electric drive This type of drive, composed of one or more dc diesel generator sets and often a double -ar propulsion motor. is used in tugs, dredges, Coast Guard cutters, and icebreakers, where maneuvering and a wide ange in propeller speed are necessary. For slow-speed operating during maneuvering, the engine speed is often reduced and the generator field excitation is altered to provide wide variation in the motor output and propeller Bridge or pilothouse control of the ship propulsion unit, without action by the engineer on watch, s used with diesel-electric drive and for small, low-powered, direct-drive, and mechanically geared diesel installations. This is the customary arrangement for tugs and dredges Modern practice for large diesel and steamships is to provide pilothouse control of the main engines and no engine-room watch except day workers and when entering and leaving port Propulsion plant monitoring is usually provided in a central control space, with chart recorders or a data storage system. All levels of automation are now being used, from simple manual surveillance of all systems in a fully manned engine space to completely unmanned system recording data and monitoring trends to pinpoint possible trouble Governors Above the operating rpm, ship propeller torque increases faster than engine or turbine torque, and thus ship propeller drive is inherently stable. Because of the ship's pitching, the propeller may lift partially out of the water and the engine may tend to race. To allow for this situation, or for propeller shafting failure. American Bureau of Shipping regulations require that a governor be fitted to limit overspeed to 15% above the rated speed A common type of governor uses oil pressure developed by small pumps incorporated with the main turbine rotors to activate the governor; low lubricating oil pressure will also shut off the steam supply With turboelectric and -electric drive, there is no mechanical connection between the generator set and turbogenerator steam or the amount of fuel injected in the diesel engine cylinder a the propulsion motor and propeller. The operating governor holds generator speed at the set value by throttling (From McGraw-Hill "Encyclopedia of Science and Technology", Vol 8, 1982) Technical Terms 1. marine engine船舶发动机 18.oil- fired燃油的 2. waterborne vessel船,水上运载器 19. marine water-. tube boiler船用水管 3. cruising speed经济航速(民 锅炉 船):巡航速度(军舰) 20. forced draft fan强力通风机 4. steam engine蒸汽机 21. turbogenerator汽轮发电机 5. steam engine汽轮机 casing外壳,箱壳 6. diesel engine柴油机 23. reduction gear减速齿轮/器 7. reciprocating engine往复式发动机 24 nozzle 喷咀,排气管 8. cylinder气(汽)缸 稳定/固定的 9. double- acting双作用 冲动级 0. piston活(柱)塞 27. reaction stage反动级 11.fed- water给水 28. kinetic energy功能 12. condenser冷凝器 oss compound system交叉复合 13. boiler锅炉,蒸汽发生器 系统 14. pressure-confining surface受压面 30. parasitic loss无功/附加损失 15. gearing齿轮装置,传动装置 31. windage loss气体阻力损失 16. rotor转子,电枢 32. gas turbine燃气轮机 otating blade旋转叶片 33. regenerator回热器Diesel-electric drive This type of drive, composed of one or more dc diesel generator sets and often a double –armature propulsion motor. is used in tugs, dredges ,Coast Guard cutters, and icebreakers, where maneuvering and a wide range in propeller speed are necessary. For slow-speed operating during maneuvering, the engine speed is often reduced and the generator field excitation is altered to provide wide variation in the motor output and propeller speed. Control arrangements Bridge or pilothouse control of the ship propulsion unit, without action by the engineer on watch, s used with diesel-electric drive and for small, low-powered, direct-drive, and mechanically geared diesel installations. This is the customary arrangement for tugs and dredges. Modern practice for large diesel and steamships is to provide pilothouse control of the main engines and no engine-room watch except day workers and when entering and leaving port. Propulsion plant monitoring is usually provided in a central control space, with chart recorders or a data storage system. All levels of automation are now being used, from simple manual surveillance of all systems in a fully manned engine space to a completely unmanned system recording data and monitoring trends to pinpoint possible trouble. Gonernors Above the operating rpm, ship propeller torque increases faster than engine or turbine torque, and thus ship propeller drive is inherently stable. Because of the ship’s pitching, the propeller may lift partially out of the water and the engine may tend to race. To allow for this situation, or for propeller shafting failure. American Bureau of Shipping regulations require that a governor be fitted to limit overspeed to 15% above the rated speed. A common type of governor uses oil pressure developed by small pumps incorporated with the main turbine rotors to activate the governor; low lubricating oil pressure will also shut off the steam supply. With turboelectric and diesel-electric drive, there is no mechanical connection between the generator set and the propulsion motor and propeller. The operating governor holds generator speed at the set value by throttling turbogenerator steam or the amount of fuel injected in the diesel engine cylinders. (From McGraw-Hill “Encyclopedia of Science and Technology”, Vol.8, 1982) Technical Terms 1. marine engine 船舶发动机 2. waterborne vessel 船，水上运载器 3. cruising speed 经济 航速（民 船）；巡航速度（军舰） 4. steam engine 蒸汽机 5. steam engine 汽轮机 6. diesel engine 柴油机 7. reciprocating engine 往复式发动机 8. cylinder 气（汽）缸 9. double-acting 双作用 10. piston 活（柱）塞 11. feed-water 给水 12. condenser 冷凝器 13. boiler 锅炉，蒸汽发生器 14. pressure-confining surface 受压面 15. gearing 齿轮装置，传动装置 16. rotor 转子，电枢 17. rotating blade 旋转叶片 18. oil-fired 燃油的 19. marine water-tube boiler 船用水管 锅炉 20. forced draft fan 强力通风机 21. turbogenerator 汽轮发电机 22. casing 外壳，箱壳 23. reduction gear 减速齿轮/器 24. nozzle 喷咀，排气管 25. stationary 稳定/固定的 26. impulse stage 冲动级 27. reaction stage 反动级 28. kinetic energy 功能 29. cross compound system 交叉复合 系统 30. parasitic loss 无功/附加损失 31. windage loss 气体阻力损失 32. gas turbine 燃气轮机 33. regenerator 回热器