Efficient Disengaging Hooks System Based on Constant-Power Speed Regulation of Frequency Converter

In the traditional port, disengaging hook system adopts a three-phase power frequency power to drive a three-phase asynchronous motor. The operation is simple and the maintenance is convenient. However, it still keeps the speed of mooring lines constant. Under the light-load condition, the work efficiency could be affected because of the low speed. To solve this problem, we start the research in speed control of disengaging hook. By using variable frequency control technology to transform the original system and using frequency converter to carry on the constant-power speed regulation, technicians also adopt vector control algorithm with PG to achieve adjustable speed of cable volume. The motor is under no load or light load state with high-speed after starting and turns into low-speed through full load. It makes motor stay in constant-power state when it works. This design solves the low-efficiency of disengaging hook in the past and makes system achieve adjustable motor speed. In this design and application, not only can technicians reduce the initial cost, but also they can reduce operating costs markedly by adopting energy-saving control equipment at the same time.