RU1778058C - Starter for hoisting machine - Google Patents

Abstract

SUMMARY OF THE INVENTION The device comprises: 1 core current controller, 1 thyristor converter, 1 core current sensor, 1 speed controller, 1 intensity adjuster, 1 speed sensor, 2 controlled keys, 1 brake torque sensor, 1 speed setting unit , 1 threshold element, 2 time delay units, 1 brake control unit, t brake, 1 lifting machine. 1 null organ, 1 logical element I. 1 ill,

Description

The invention relates to control devices for hoisting machines, and can be used in the automation of various hoisting mechanisms.

The aim of the invention is to increase the reliability of the lifting machine.

The drawing shows a functional diagram of the proposed device.

The device comprises a current regulator 1 of the motor core 2 of the lifting motor with a thyristor converter 3. The output of the current sensor 4 of the motor core is connected to one of the inputs of the current controller 1, and the output of the speed controller 5 to the other input. The first, second and third inputs of the latter are connected to the outputs behind the intensity sensor 6, the speed sensor 7 and the second controlled key 8. The input of the latter is connected to the brake torque sensor 9, which can be used as a strain gauge placed on

brake beam. In this case, it is measured not the maximum potentially developed braking torque proportional to the force of the normal pressure of the pads on the torus-1 rim, but the actually developed braking moment, when the machine is stationary, equal to

Mt (Mg-Md).

where Mr, MD - respectively, the static moment of the load and the motor moment.

The output of the speed setting unit 10 is connected to the input of the threshold device 11 and, through a controlled key 12, to the input of the intensity adjuster 6. The output of the threshold device 11 is connected to the control input of the key 8 and through the logic element And 19 and the time delay unit 13, to the block 14 of the brake control 15 of the lifting machine 16. The output of block 13 through the second time delay block 17 is connected to the control input of key 12.

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The device operates as follows.

Before starting the start, the lifting machine 16 is braked by the brake 15, while the magnitude of the braking moment measured by the sensor 9 is equal to the load moment. The signal of the set speed of the lifting machine 16 comes from the speed setting unit 10, which can be, for example, a synchro control device. When this signal is generated, threshold device 11 is activated and key 8 is closed, feedback signal on the braking torque from sensor 9 is supplied to speed controller 5. Since the lifting machine 16 is still stationary, the speed feedback signal from sensor 7 is 0. The system is closed by braking torque and functions as a braking torque control system. The braking torque controller is the speed controller 5: a zero signal from the master 6 is supplied to its inputs (since key 12 is still open), and the feedback signal from sensor 9 is used. The controller 5 must have a proportional-integral ( PI) structure. The closed control system fulfills the zero reference, the internal current control circuit enters into operation with its own regulator 1 and sensor 4, the voltage at the output of the thyristor converter 3 and the current in the cortex of the motor 2 appears. The system comes to a stable state after that as the core current reaches a value at which the braking torque (signal at the output of the sensor 9) becomes equal to zero. There is a complete balancing of the motor moment of the load moment. At the output of the null-organ 18, a logical unit appears at the second input of the And 19 element. Since its first input also has a logical unit (from the output of the threshold device 11), at the output of the And 19 logic element also appears a logical unit that applied to the brake control unit 14 via the time delay unit 13 (a time delay is necessary to eliminate the influence of a possible bounce of the null-organ 18). The braking of the lifting machine 16 takes place. After the braking is completed, the key 12 is closed (the setting of the time delay unit 17 is equal to or slightly longer than the braking time), the signal from the speed setting unit 10 is input to the intensity adjuster 6. At the output of master 6, a speed chart is generated with a jerk limitation that is processed by the speed control system. The signal from the output of the sensor 9 is zero (since the machine 16 is completely braked) and does not affect the nature of the speed control process.

If for some reason the balancing did not happen (for example, due to overload of the lifting vessel, malfunction of the thyristor converter 3, etc.),

the output of the sensor 9, the signal will not be 0. Therefore, at the output of the zero-organ 18, and therefore at the output of the logic element 19, there will be a logical zero. The machine will not brake and emergency

a situation related to a possible subsidence of a loaded lifting vessel is excluded.

Thus, the proposed device eliminates the possibility of subsidence of the loaded lifting vessel after disinhibition due to overload or malfunctions in the thyristor converter. This significantly increases the reliability of the lifting machine.

Claims (1)

The claims A device for starting the lifting machine, comprising a speed reference unit, the output of which is connected via the first controlled key and an intensity adjuster to the first input of the speed controller, the output of which is connected to the first input of the motor current regulator, the output of which is connected to the control input of the thyristor converter connected in series with its power clamps to the motor and the motor core current sensor, the output of the latter is connected to the second input of the motor core current regulator, mounted coaxially with engine the speed sensor is connected to the second input of the speed controller, the third input of which through the second controlled key is connected to the output of the brake torque sensor, the output of the reference unit through the threshold element connected to the control input of the second controlled key, the output of the first time delay unit is connected through the brake control unit to the brake of the lifting machine, and through the second time delay unit to connected to the control input of the first controlled key, characterized in that. in order to increase the reliability of the work of the lifting machine, a zero-organ and an element I. are introduced into it; moreover, the output of the brake torque sensor through a zero-organ is connected to the first output of the element And, the second input of which is connected to the output of the threshold element, and the output - to the input of the first time delay block.