Improvements relating to Marine Electrically Controlled Steering Gear.

摘要

18,444. Haigh, B. P. Aug. 15. Synchronous movements. - In electrically controlled marine steering-gear comprising a pair of electric motors M', M2, Fig. 1, arranged to work in approximate synchronism, in combination with two hunting switches D3, D' and D', D2, the latter of which controls the electric motor driven gear, or with a hunting switch and a hunting valve, the latter of which controls the power supply to the gear, means are provided for correcting deviations from exact synchronism. Whenever the controlling hand.wheel HW passes a certain predetermined position, for example amidships, an interruption of the normal action is arranged to take place either by opening the circuit of one or both of the motors M1, M2 or by de-energizing a magnetic clutch MC between the motor M1 and the hunting switch or valve D', D2. By this means the disk D2 of the hunting switch or valve situated near the rubber, which normally follows the movement of the disk D3 of the other hunting-switch, is temporarily disconnected therefrom. At the same time, if the motors M', M2 have not run synchronously, the disk D' is caused to centre itself, i.e. to take up the amidships or other predetermined position, by purely mechanical means, such as springs, balance weights, or fluid pistons, or by means brought into action electrically from a switch connected to the hand-wheel. The electrical action is effected by an electro-magnet, or an additional electric motor, or, as shown in the diagram, Fig. 2, the motor M' may be utilized for this purpose. In this diagram, three-phase induction motors are shown ; a rotor R1 and a stator S' represent the motor M' and a rotor R2 and stator S2 represent the motor M2. In normal working, before the hand - wheel reaches the amidships position, the only connexion of the motor M' to the lines I, II, III is through a switch Y', the two motors then being in approximate synchronism. On reaching the amidships position, the hand-wheel opens the switch Y', and closes a switch Y2, connecting the motor M1 in a circuit independent of the motor M2. The circuit also includes a reversing switch X operated by the rudder so that the motor runs in one or the other direction according as the rudder is on one or the other side of the amidships position, and breaks circuit when the hunting switch D2 and the rudder reach the amidships position. The normal working is resumed when the hand-wheel passes the amidships position. Direct current motors or any other types may be used instead of induction motors. According to the Provisional Specification, direct-current motors may have slip-rings attached so as to assist them to move synchronously.