SU958217A1 - Apparatus for transfer of cargo between ships on rough seas - Google Patents

Description

(5) DEVICE FOR TRANSFER OF CARGOES BETWEEN SHIPS IN THE SEA UNDER THE CONDITIONS OF QUALITY

The invention relates to shipbuilding, in particular, to devices for transferring cargo between ships to sea in pitching conditions. A device is known for transferring cargo between ships at sea in pitching conditions, comprising rope branches, wound onto two traction winches connected to interconnected and second direct current electric motors having excitation windings, a cargo trolley attached to one - from the branches of the rope and kinematically connected with the other branch of the cable, as well as the electronic unit controlling the operation mode of the electric motors, including setting devices for tension signals in the branches of the rope and signals for moving the trolley and two Each circuit connected to each appropriate traction winch and containing each series-connected adder, tension controller and thyristor converter, as well as a tension sensor on the same branch of the rope, the output of which and the outputs of the aforementioned setters are connected to the inputs of the first and second adders 11 A disadvantage of the known device is that it consumes a lot of electricity. The purpose of the invention is to reduce the cost of the device and the cost of electricity. The goal is achieved by the fact that the electronic control unit of the electric motor operation is equipped with a current sensor connected to the first electric motor, an inverter and an electric circuit from a series-connected current meter, additional adder, control current and additional thyristor converter connected to the outputs current and the second motor, and the setpoint signal movement is connected to the first adder through the signal amplifier displacement, with the second adder h Res said amplifier and coupled with it ny inverter, and outputs thyristor converters connected respectively to the excitation windings of motors. FIG. 1 dan Kinematic device circuit; in fig. 2 -. Functional diagram of the device; on Fig.Z external characteristics of the power thyristor converter TP1; in fig. 4 - adjustment characteristic of the power thyristor converter ТП1; in fig. 5 adjustment characteristic of low-power thyristor converters TP2, TPZ; in fig. 6 shows the mechanical characteristics of the electric motors when performing the rope tension operation; FIG. 7 shows the mechanical characteristics of the electric motors when performing the trolley movement operation; in fig. 8 - mechanical characteristics of electric motors when practicing pitching in the event of an increase in tension in the ropes, where E, E, and electromotive force of electric motors; in fig. 9 - mechanical characteristics of electric motors when practicing rolling in case of increased tension in the rope, when -E (0; in Fig. 10 - mechanical characteristics of electric motors when practicing rolling in case of decreasing tension in the cables. Device for transferring cargo between The transmitting vessel 1 and the receiving vessel 2 contain masts 3 and 4 between which the branches of the rope 5 are pulled. The load is in the trolley 6 connected to block 7 moving along the upper branch of the rope 5 and rigidly connected to the lower branch of the rope whose loop rounding block 8 n the mast of the vessel 2, and the two ends, the envelope blocks 9 and 10 on the mast 3 of the vessel 1, are connected to the traction winches 11 and 12. The winches 11 and 12 are connected by gearboxes 13 and 1 to their electric motors 15 and 1b of direct current. connected to the additional (power) thyristor converter TP1. The control signal U: / the thyristor converter TP1 comes from the output of current regulator 17. The additional signal 55 of this regulator 18 is supplied with a current reference signal in the Uj-T circuit with current setpoint 19 output and signal of a joyous communication by current of the power circuit pi current sensor 20. The windings 21 and 22 of the excitation of the electric motors 15 and 16 are connected to low-power thyristor converters TP2 and TPZ. The control signals of the thyristor converters and come from the outputs of the regulators 23 and 2 tension. The adders 25 and 26 of these regulators are supplied with the voltage setting signal UjH from the output of the tension setting device 27 and the feedback signals for the tension of the sensors 28 and 29 and, respectively, to the adder 25 - the output signal of the displacement amplifier 30, and to the adder 26 , - the output signal of the inverter 31i to the input of which is fed the output signal of the displacement amplifier 30. The input signal of the displacement amplifier is the signal Uj, coming from the output of the setpoint adjuster 32 of the displacement signal. The device operates as follows. in the INITIAL state, the voltage of the thyristor converters TP1, TP2, TPZ is zero, the control signals Uy ,, are also equal to zero, and the control signal Uy is 0.5 (Fig.). Electric motors are fixed. To perform the set-up operation, first set a predetermined amount of current in the core chain of the electric motors 15 and 1b. For this, the current setting device 19 sets the nominal value of the current setting signal and at the input of the adder 18 and further at the input of the current regulator 17, which leads to an increase in the control signal U. At the input of the thyristor switch TP1 (FIG. 2), the output of this converter the maximum voltage (direct and | p-, in Fig. 3), which leads to an increase in the current in the armature circuits of the electric motors 15 and 1b, and as soon as the current of the electric motors exceeds the value of the bale at point A, corresponding to the specified value, the output current sensor 20 appears with I drove the feedback, which reduces the voltage thyristor converter TA1, limiting the amount of current in the anchor chains predetermined value. The operating point of the thyristor transducer TP1 moves downwards to intermediate external characteristics (u | p ...) to point B, and the current at point B differs from the current at point A by the value of the static error of the current control loop. In the steady-state mode, the voltage at the output of the thyristor converter TP1 is minimal and equal. where Zz is the rated current of the Korean electric motors 15 and 16; cRa is the total resistance of the core circuits of electric motors. The control signal at the input of this converter is close to 0.5 (operating point B in Fig. A), and the electric motors 15 and 16 are in stand-by mode. The excitation flows of the electric motors are equal to zero, and the tension of the cableway is also equal to to zero. Next, a signal for setting the tension 11d from the output of the setpoint adjuster 27 is supplied to the adders 25 and 26 and then to the inputs of the tension regulators 23 and 2k (Fig. 2). This leads to the appearance of control signals and, and U, at the inputs of the thyristor converters TP2, TPZ, and to the appearance of voltage at the output of these converters. Since the signals of the tension sensors 28 and 29 are zero, the maximum voltage (operating point A, fig. 5) at the outputs of TP2 and TPZ sets maximum excitation fluxes in electric motors 15 and 16, which are determined by the saturation of the magnetic circuit. When applying to the adders 25 and 26 of the same signal U ar, the electric motors 15 and 16 operate according to the same mechanical characteristics (curves uj (S) 1 and "JO (S) 2 in Fig. 6) and accelerate to speed; rotation defined by the expression p. UJ, UJ.

thyristor voltage

TP1 converter; coefficient determined by the design of the motor;

maximum value of a stream of electric motors.

WITH

W

F

m

where Сц (, -const is the constant coefficient determined by the design of the electric motor.

The magnitude of the thrust moment of each electric motor corresponds to a given current as the motors accelerate. root chains, defined by the expression 4VS). where E, E rt- EMF, respectively, of electric motors 15 and 16, decreases, which leads to a decrease in the signal at the output of current sensor 20, and consequently, an increase in control signal Uj /, and in accordance with the control characteristic of the thyristor converter TP1 (FIG. k) The effect rises until the current in the core circuit is restored to its previous value. In this case, the acceleration of electric motors 15 and 16 takes place practically at a constant current. After acceleration, electric motors; work at points B and B1 (curves iu (S) 1 and u (S) 2 of Fig. 6) and choose the slack of the rope with maximum moments. As the slack of the rope is selected, the tension in it increases, and consequently, the signals at the outputs of the tension sensors 28 and 2E. The voltages of the thyristor & transformers TP2, TPZ decrease, their working points move from point A to point B (Fig. 5, the magnetic fluxes of electric motors t5 and 16 decrease. At the same time, the current of the electric motor tS and 16 and the circuit are reduced adjusting the current reduces the voltage of the thyristor converter TP1, maintaining the current in the core circuit constant.Since the decrease in magnetic fluxes occurs to a lesser extent than the decrease in the voltage of the thyristor converter TP1, then in accordance with expression (2) and the rotations of the electric motors 15 and 16. In the steady state, the electric motors are in the standby current mode (operating point D, Fig. 6) and develop the same traction moments equal to tension and, as can be seen from the expression ( k) is determined by the magnitude of the magnetic flux. In this case, the voltage of the thyristor converter TP1 is minimal (operating point B, Fig. 3) and is determined by the expression (1). To move the cart 6, for example, the reference signal is sent to vessel 2 by the displacement 32 Ujj, to the input of displacement amplifier 30 (FIG. 2) from the output of which a signal is fed to the adder 25 and to the input of the inverter 31. From the output of the inverter 3t, an output signal equal in magnitude and opposite in sign to the output is supplied to the input of the adder 26 (press the signal to the displacement amplifier. This increases the control signal Uyn at the input of the thyristor converter TP2 and the control signal at the input of the thyristor converter TPZ is reduced. The tension control circuits of the electric motors 15 and 16 fulfill this signal () in such a way that the magnetic flux of the electric motor 15 increases and the magnetic flux of the electric motor 16 is reduced by the amount of df .. The magnitude of the change in fluxes LF is determined by the static error of the tension control loops. As a result of the change in magnetic fluxes, the stationing time of the electric motor 15 increases and the moment of stationing of the electric motor 16 decreases. 15 increases and the tension in the cable branch of the electric motor 16 decreases, the mechanical characteristic of the electric motor 15 (curve w (5) 1 igi. 7) is mixed to the right (curve 5) 1 of FIG. 6), the operating point changes from point A to point B. At the same time, the mechanical characteristic of the electric motor 16 (curve io (S) 2 of FIG. 7) is shifted to the left (curve ijj (S) 2 of FIG. 6), the operating point of this electric motor passes from point A to point B As soon as the force in the rope branch of the electric motor 1b becomes greater than the force in the other branch, and it is enough to turn the winch of the electric motor 16 to the sides, the movement of those beds 6 in the direction of the receiving vessel begins. The motor 15 continues to operate in the propulsion mode, its speed increases in accordance with the characteristic Uj (S) 1, and the tension in the rope branch associated with it decreases. At the same time, the electric motor 16 begins to rotate in the opposite direction, goes into the generator mode and feeds the rotor circuit of the electric motor 15. The rotational speed of the electric motor 16 increases in accordance with the mechanical characteristic (l) (5) 2 Magnetic flux and tension in the cable branch of the electric motor 16 increase. As soon as the electric motors 15 and 16 are accelerated, the current control loop comes into operation, which increases the voltage of the thyristor converter TP1 and restores the set current value in the core circuit. The overclocking of the electric motor takes place practically at a constant current. In the established mode, the electric motor operates at point G (Fig. 7) with practically constant tension in the branches of the rope and the same rotational speed equal to tn-1-o and U) U) S From expression (5) it follows that at the maximum speed of movement of the trolley (which corresponds to the maximum & F voltage of the thyristor converter TP1 is also maximum, its operating point is at point A (Fig. 3). Since during the movement of the cargo trolley some of the power of the electric motor 15 returns back to the main circuit by an electric motor 16 and p power generator, the power consumed by the thyristor converter TP1 from the network decreases. The value of this power is determined by the expression: p p. d is the power consumed by one electric motor; pj is the loss in the electric motor circuit; Shi, dfc — angular rotational speed and the corresponding increment of the magnetic flux of the electric motor at the maximum speed of movement of the trolley. From expressions (6) and (7) it follows that the power of the thyristor converter TP1 is equal to the power of one electric motor, which reduces electricity costs and reduces the initial cost of the device. When the vessels are rolling or diverging, the tension in the rope changes. Automatic tension control is as follows. When the trolley 6 moves to the vessel 2 (Fig. 2) in the established mode, the technical characteristics of the electric motors are arranged as shown in FIG. 8 and FIG. 9 (curves uj (S) l and uj (S) 2, operating point A). Let vessel 1 remain motionless and the vessel 2 swing. If vessel 2 swings to the right, the tension in the wind in the rope increases by the value of L5 and the speed of the electric motor 15 decreases, and the speed of the electric motor 16 increases, and the motor 16 to point A. (At the same time, the feedback signals of sensors 28 and 29 increase, which leads to a decrease in the control signal Uy at the inputs of thyristor converters TP2, TP As a result, the voltages at the outputs of these thyristors decrease Transducers and magnetic fluxes of electric motors 15 and 16, and, consequently, tension in the branches of the rope. The working sections of the mechanical characteristics of the electric motors are shifted to the left to point Aj (Fig. 8 and 9), and the tension generated by the electric motors decreases. There are two possible modes of operation of the thyristor converter TP 1. In the first mode, the power returned to the core circuit by the electric motor to point A is greater than the power required by the electric motor 15 at point A (Fig. eight). This happens when yes E-Epo. In accordance with the expression (o) for the current of the thyristor converter TP1,. ..3,., TP1 N the mode of operation of the thyristor by transforming the rectifying body. The control signal (FIG.) Of this converter is greater than 0.5. Electric motors 15 and 16 operate on mechanical characteristics and) (5) 1i and S (S) 2 (Fig. 8), corresponding to a lower voltage of the thyristor converter TP1. In the second mode, the power returned to the main circuit by the electric motor at point A (Fig. 9) is greater than the power of the electric motor 15 at point A, or the electric motor 15 under the effect of rolling moves to the generator mode (in this case, point A is located below the axis of moments). In both cases, the condition is satisfied. Then, in accordance with expression (8), the operation mode of the thyristor converter TP1 is inverter, since the control signal Uj becomes less than 0.5 due to the feedback of the current control loop, and the thyristor converter TP1 starts working on external characteristics, tics or UTJ ,, (FIG. 3). Electric motors operate on mechanical characteristics. X U) (S) l and uj (S) 2 (Fig. 9), corresponding to the negative voltage of the thyristor converter TP1. . In the steady-state mode, the tension in the rope remains almost unchanged, So, equal to the sum of the tensions SI produced by the electric motors, and L51, created by rolling, and the current of the thyristor converter TP1 is equal to the nominal one. Electric motors operate at different speeds at points B and C (Figs. 8 and 9). When the tension in the rope decreases (the vessel 2 swings to the left), the system performs this signal so that the mechanical characteristics of the electric motors are shifted to the right to the point At (curves (5) 1, u) (S) 2 of FIG. 10), and the tension on the branches of the rope, created by electric motors, increases to the tension S (Fig. 10). The total tension in the rope is equal to the difference between the tensions S, created by electric motors, and L51, created by rolling. The voltage of the thyristor converter TP1 at point A1. is greater than the voltage at point A, and the converter current is nominal (current control loop is working). Electric motors operate at different speeds at points B and C (Fig. 10). When both vessels are rolling together in the cableway, the algebraic summation of the tension created by the rolling of ships 1 and 2 occurs. Therefore, the system works out a net effect equal to the algebraic sum of tension created by the swing of ships 1 and 2. Similarly, the tension in the ropes is maintained at divergence or convergence of courts. To stop the cart 6, the speed signal is reduced to zero and the cart stops. The system maintains the tension in the ropes. When the reverse, i.e., when the load carriage returns to vessel 1, the polarity of the driving signal in the movement speed Ugrff changes, which leads to an increase in the control signal at the input of the thyristor converter of the TPZ and a decrease in the signal Uy, at the input of the thyristor converter TP2 (Fig. 2 ). As a result, the magnetic flux of the electric motor 16 and the tension in the branches of the rope connected with it increase, and the magnetic flux of the electric motor of .15 and nat decreases. in the branch of the rope associated with this electric motor. The motor 16 operates in motor mode, the motor 15 goes into generator mode and feeds the rotor circuit of the motor 16, and the thyristor converter TP1 operates with a nominal current. In this case, the direction of the currents of the TP1, TP2, TPZ converters remains unchanged, which allows the use of non-reversible converters,

and consequently, reduces the cost and inertia of the system.

Lifting and lowering of the trolley 6 to the deck of the transmitting or receiving vessel is carried out by changing the tension in the cableway by influencing the magnetic fluxes of the electric motors or the current of the electric motors' core circuits.

As can be seen from expressions (6) and (7), the use of the proposed device allows to reduce the installed power of the power thyristor converter TP1 by about 2 times with the same power of the traction electric motors, which reduces the costs

a driver connected to its outputs with a current sensor and a second electric motor; the Motion signal setter is connected to the first adder via a displacement signal amplifier, to the second adder via said amplifier and an inverter connected to it, and the outputs of the thyristor pressors are connected respectively to the motor windings .

Information sources,

taken into account in the examination

. 1. USSR author's certificate

Application number 2909 51, class B 63 B 27/30,

Claims (1)

. TB.O + .vO (prototype). 712 electricity during the transfer of goods at sea and the cost of the device. Apparatus of the Invention A device for transferring cargo between ships and the sea in pitching conditions, comprising rope branches wound on two traction winches connected to interconnected first and second DC motors having field windings, a load truck, with " attached to one of the branches of the rope and kinematically connected with the other branch of the rope, as well as an electronic control unit operation mode. Electric motors, including setting devices for tension signals in the branches of the rope and signals for moving cargo trolleys and two electrical circuits connected each with a corresponding traction winch and containing each series-connected adder, tension controller and thyristor converter, as well as a rope branch tension sensor, the output of which and the outputs of the aforementioned setters are connected to the inputs of the first and second adders, characterized in that, in order to reduce the cost of the device and the cost of electricity, the electronic node controlling the operation of the electric motors is equipped with a current sensor connected to the first electric motor Spruce, inverter and electrical circuit of the series-connected current setting unit, additional adder, current controller and additional thyristor converter 1.0 tats fS)