tailieunhanh - Lesson19- The Application of Electricity on Board

Tham khảo tài liệu 'lesson19- the application of electricity on board', ngoại ngữ, anh văn thương mại phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Lesson19- The Application of Electricity on Board 1. Electrical Drive for Machinery The electrical drive system principally contains motor drive mechanism and control unit. Among them the motor is cast for the part of a prime mover in the electrical drive system whose function is to transform electrical energy into mechanical energy and whose types and capacity depend on the requirements of the relevant working machinery. Both motors and working machinery are either directly connected or joined together into one unit by a speed reduction drive mechanism. With regard to the control unit it has been developing rapidly from a simple relay contactor to a complicated control system of various automatic components. In fact there is a lot of aux. machinery on board which is generally of electrical drive and electromagnetic contactor control. For some aux. machinery however a few additional control components are adopted to relieve the crew of the routine operation and maintenance such as pressure relay temperature relay level relay etc. In addition the anchoring and mooring equipment is also common deck machinery. Electrical-driven anchor windlasses and anchor winches are now widely employed. It is easy enough to lower an anchor by gravity but there are several stages for the anchor retaking that are of varied speeds. Therefore a motor will run at a higher speed if the load is light and has to run at a minimum speed when the anchor approaches the hawsepipe. To fulfill the mission a control circuit of relay contactors with the master controller is to be arranged to regulate the motor speed. 2. The Electric Steering Gear System The three types for the electric steering gear system are as follows . Hand Steering By hand steering its control circuit is normally to be of relay contactors. In order to safeguard the reliable operation of the steering gear two motors are to be provided with any one of them in service and the other in the state of stand-by. The hand steering .