3 INVERTER-controlled All-weather Gantry Crane
3-1 Introduction
The inverter(frequency control) drive system is applied widely to almost all of the industrial fields, while the ocean field is behind the other fields in the adoption of the inverter drive system because of the too severe working environment as compared with general working environment on the land, and the direct current motor drive controlled by Thyristor has been mainly used in the field. However, demands for energy-saving and high reliability in marine transportation are rapidly accelerating the feasibility of the commercialization of the inverter for ships.
One of the types of ships which are now in great demand is the Open Hatch-structured multi-purpose bulk carrier with box-shaped holds, which is used to transport bulk, containers and timber together and on which a gantry crane provided with a rain protection system is installed. Tsuji already manufactured more than 20 sets of high-performance allweather gantry cranes. The ships with those gantry cranes installed on them have entered the North American, Canadian, Japanese and European services.
(In this connection, the total number of delivered gantry cranes is 165 sets.)
On the basis of those practical technologies, Tsuji has commercialized the newest version of INVERTER drive gantry crane, the outline of which is described below.
3-2 Concept of Development
Features of INVERTER Drive System
1) Maintenance free: No need of maintenance for electrical vital parts because of no mechanical consumables such as brushes etc.
2) Energy-saving: More efficient loading and unloading by highly
