Andrei A. Panasenko Admiral Nevelskoy Maritime State University, Vladivostok Zinaida V. Korshunova Admiral Nevelskoy Maritime State University, Vladivostok Abstract: The present article is composed with the aim of informing cadets – future electrical engineers on the ship`s equipment, involving Azipod as a part of a power plant. The Azipod System: it`s construction, high dynamic characteristics, optimal location, reduction of mechanical components, and the length of the hull are considered, promoting useful volume of space for cargo, weakening the pressure on metal structures, increase of redundancy and maneuverability; ship`s reliability and safety; some advantages and disadvantages of the main components of the electrical installation.Keywords: installation, propeller, motor, shaft, propulsion, pod, power plant, provide, eliminate, allow, dynamic positioning, stern thrusters, cost saving
One of the standards for cadet`s competence evaluation is his capability to be able to explain electrical and electronic systems and controlling systems with the help of regulations and diagrams and also to understand theoretical aspects and then to master professional knowledge and to gain practical skills.
Professional English has been and remains one of the most important aspects of work for a technical university and is widely used at our Admiral Nevelskoy Maritime State University in the training of future marine specialists, in particular, the future Ship Electrical Engineer. At specialty lessons and professional English classes, the topics of servicing both auxiliary mechanisms and the main ship`s power system are discussed , requiring the practical knowledge of new terms phrases, sentences, the text itself and reading schemes.
So the suggested material of the application of the new constructive Azipod Concept in the English language will be of great help to study and understand the modern electrical submerged installation and it`s interaction with other electrical systems on the ship in English. Let’s focus on the role of it`s construction, characteristics and other aspects.
In 1987, specialists from ABB (Asea Brown Boveri Ltd.) proposed a new power plant (Finnish patent FI76977), called Azipod (Azimuthing Podded Drive) – an azimuth gondola-type propulsion drive. Figure 1 shows a diagram of the Azipod system, for which ABB received a patent of the Russian Federation [1].
In this installation, the propulsion motor is placed in a hermetic pod 1. The shaft line 3, on which the rotor of the electric motor is mounted, is removed from the pod through a hermetic seal. A propeller 4 is fixed at the end of the shafting. In the upper part, a vertical shaft 2 is welded to the pod which forms a single structure with the pod. Both of them are installed under the stern of the vessel in such a way that the open upper end of the shaft goes to the deck above the waterline. On this deck, the systems required for the operation of the power plant are located. The diesel generator generates electricity, which is transmitted through cable connections to the electric motor. The electric motor that provides rotation of the propeller is located in a special pod. The screw is on a horizontal axis, the number of mechanical gears is reduced – as a result, the maximum propulsion coefficient is achieved. The rudder propeller has a turning angle of up to 3600, which significantly increases the ship’s controllability.
The CRP Azipod (contra-rotating propeller) installation provides increased maneuverability and redundancy compared with traditional twin-shaft power plants. The second shaft line and the stern thruster become unnecessary – a significant useful volume on the ship is released. In addition, CRP Azipod improves efficiency propulsion power unit (PPU), the required power of the PPU is reduced by 10% – 15%.
ABB is a leader in the development of Azipod systems, but many foreign firms: Siemens, Chattel, Aquamaster, Mermaid and others are developing similar propulsion systems. Siemens and Schottel jointly created a gondola unit with two propellers on the face sides of a pod and rotating in opposite directions. A synchronous electric motor with permanent magnets is used as a drive motor. In general, the efficiency of the developed propulsion plant is increased by 10% due to the use of two propellers and a permanent magnet motor.
The whole installation, in addition to the actual elements of azipod system, includes a frequency converter, power plant (generators and power distribution system) and automation and remote control systems for each of the listed elements (Fig. 2). The Azipod helical steering column consists of a high-torque electric motor located in a separate pod housing (Fig. 1, 2) The propeller is mounted directly on the shaft of the electric motor, which made it possible to transfer torque from the engine directly to the propeller, bypassing intermediate shafts or gearboxes. Electricity for azipod is supplied from the ship’s power plant using flexible cables.
The absenсe of the intermediate elements of the propulsive system allowed to eliminate the energy losses that occur in them during the transmitting energy from the engine shaft to the propeller. The installation is fixed outside the vessel’s hull by means of a hinge mechanism and can rotate around a vertical axis at 360o, and hence better maneuverability of the vessel, both in course and speed compared to conventional propulsion systems. The turning system is hydraulic.
Azipod propulsion systems are of great importance for using them on ice breakers and ice ships. One example of Azipod application is a double-acting tanker that in open water moves like any other cargo vessel but in ice she moves stern-forward like an icebreaker, for which the stern of such a vessel is equipped with an icebreaking ice reinforcement. Modern icebreaking ships, as a rule, have a full-width, closed-type navigating bridge. The consoles are mounted on the wings of the bridge what allows the captain simultaneously to control the modules and monitor the ship’s surroundings at the same time, e.g. in the complex operations such as mooring at a berth that is difficult to approach because of ice.
The control console is usually equipped with workstation monitor, the means of communication, telegraph and joysticks for manual control of Azipod thrusters (Fig.3)
With the help of joysticks the captain can change the speed of the ship, by increasing or decreasing the number of revolutions of the thrusters. and set the desired angle of rotation of the propulsion modules to change the propeller thrust direction by turning joystick around its axis. The position of the modules is also monitored on special indicators near the joysticks.
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