Electro-hydraulic winches do not call for special mention as they use a continuous running motor, which can be either a.c. or d.c. They can be operated either singly or in groups from one pump. Many electrical deck auxiliary schemes make use of contactors for control purposes and where these are of such size and numbers as to warrant it they can be accommodated in a separate contactor deckhouse instead of in the winch assembly. This increases the amount of cabling but on the other hand it economises deck space in the vicinity of the winch, making for cleaner lines and unobstructed viewing by the operator. It also facilitates maintenance work which in any case is not always opportune to carry out when the ship is in port and when the winches are in use. While at sea maintenance can be carried out under protection from the elements. In every winch, etc., in which the load is lowered while the motor is mechanically coupled such as in systems employing power lowering it is essential to prevent the load taking charge and lowering at a speed which will damage the motor armature. To safeguard against this contingency centrifugal brakes are provided in some cases and they are so set as to enable heavy loads to be lowered with an
hese auxiliaries, in the main, comprise cargo winches (which may include warping as a subsidiary duty), cranes, capstans, warping winches, windlasses and hatch-cover winches . Except for cranes, each of these may sometimes be used for duties other than those for which they are primarily intended. The systems of control as between these various applications bear a similarity but with variations to suit the operating conditions. It will be convenient to deal with them under their different headings, but there are divergencies between the methods favoured by different makers and descriptions will therefore be confined to representative schemes. Electro-hydraulic winches do not call for special mention as they use a continuous running motor, which can be either a.c. or d.c. They can be operated either singly or in groups from one pump. Many electrical deck auxiliary schemes make use of contactors for control purposes and where these are of such size and numbers as to war...
Comments
Post a Comment