SU1577055A1 - Dc electric drive for drilling winch - Google Patents

Abstract

The invention relates to electrical engineering and can be used in direct current thyristor electric drives with reversal of the direction of rotation. The aim of the invention is to increase the reliability of the drive by increasing the accuracy of determining its mode of operation. The device contains two modules 17 and 18 for allocating a module, a sign-sensitive relay element 19, a latch 20, a logical element NOT 21, AND-NOT logic elements 22-24, as well as a controllable switch 14 and control keys 15 and 16 controlling the mode operation of the thyristor converter 2. The device allows to determine the mode in which the speed feedback signal disappeared and, in order to localize the emergency situation, carry out a differentiation of either transferring the thyristor converter 2 to the inverter mode or its breaking down 1 il.

Description

The speed feedback signal disappeared, and to localize the emergency situation, transfer the thyristor converter 2 to the inverter mode, or lock it, differentially. 1 il.

The invention relates to electrical engineering, in particular to thyristor DC drives with reverse direction of rotation of an electric motor.

The purpose of the invention is to increase the reliability of operation of the electric drive due to a more accurate determination of its mode of operation.

The drawing shows a functional diagram of the electric drive.

The drawworks DC electric drive contains an electric motor, the root winding 1 of which is connected to the thyristor converter 2, the control circuit of which includes serially connected speed setting controller 3 and speed controller 4 with limiting unit 5 and the core current regulator 6 connected to the inputs of the corresponding regulators by sensors 7 and 8 of speed and current, and motor excitation winding 9 is connected to the output of excitation control system 10, the inputs of which are connected to the outputs of current sensor 8 op, voltage sensor 11 and on the bark of drive current sensor 12, the speed sensor 7 is connected to the winch drum 13. The actuator also contains a controllable switch 14, two controllable keys 15 and 16, a module allocation units 17 and 18, a sign-sensitive relay element 19, a level lock 20, a HE 21 logical element, AND-22-2.4 logic elements and different polarity sources 25 and 26 of the reference voltage, wherein the output of the speed regulator 4 is connected to the input of the sign-sensitive relay element 19, the first output of which is connected to the first input of the first logical element AND-NOT 22, and the second output to the first input of the second logical element I- NOT 23, output d The voltage sensor 11 on the crust is connected through the serially connected first block 17 of the module and the latch 20 of the level connected to the second inputs of the logical elements AND-NOT and 23, the output of the sensor 7 is scopfn through the serially connected block 18 of the module and the logical element HE 21 It is connected with the third inputs of the logical elements AND-NOT 22 and 23, the output of the first of which is connected to the first input of the third logical element IS-NOT 24 and the control input of the first control switch 15 connected between the source 25 of the negative reference voltage and the first input of the controlled switch 14, the output of the second logical element AND-NE 23 is connected to the second input of the third logical element AND-NOT 24 and to the control input of the controlled Key 16 connected between the source 26 of the positive reference voltage and

the first input of the controlled switch 14, the second input of which is connected with the output of the speed regulator 4, the output with the master input of the current regulator 6 cor, and the output of the third logic element

I-NOT is connected to the control input of the controllable switch 14, the winch drum 13 is connected to the electric motor via a tire-pneumatic clutch 27, and to the speed sensor 7 by

chain drive 28,

The drive works as follows.

In the stand-alone mode of the electric drive, the signals at the outputs of speed controller 4, speed sensor 7 and voltage sensor 11 are equal to zero / With such a combination of analog signals, the outputs of logical elements NAND-22 and 23 contain signals of logical units, and at the output of logical element I -NO 24 - logical zero signal. Due to this, the controlled switch 14 is in such a position that the output of the speed controller 4 is connected to the driver input of the current controller 6

The core and the outputs of both the first 15 and the second 16 controlled keys are disconnected from sources 25 and 26, respectively, of negative and positive reference voltages: The drive has been prepared to process the signal of the speed reference unit 3.

When the drive operates in the motor mode in the direction of lift, there is at the output of the speed controller 4

the signal is positive polarity, so the first output of the signal-sensitive relay element 19 is a signal of a logical unit, and the second output is zero. Since the outputs of the speed sensors 7

and voltage 11, the corresponding signals are present;

21 - zero With such a combination of logical signals at the inputs of the logical elements AND-NOT 22 and 23, a signal of a logical unit is present at each of their outputs, which leads to the appearance of the signal of the logical zero at the output of the third logical element AND-NOT 24. Therefore, the controlled switch 14 is in the position when the output of the speed controller 4 is connected to the driver input of the current regulator 6, and the outputs of both the first 15 and the second 16 Controlled keys are disconnected from sources 25 and 26, respectively, of negative and positive reference voltage. zheniy.

When the feedback signal on speed disappears (malfunction or disconnection of bus-pneumatic clutch 27, interruption of the chain transmission 28, interruption or short circuit in the speed sensor 7 circuit), the following occurs. The polarity of the signal and the output of the speed controller 4 does not change, remaining positive, and at the third inputs of the NAND logic elements

22 and 23, connected to the output of the HE 21 logical element, the signals of the logical unit appear. This leads to the fact that at all three inputs of the first logical element IS-NOT 22 the logical signals have a single value, while the signal of the logical zero is still present at the first input of the second logical element IS-NOT 23. With such a combination of logical signals, the logical zero signal appears at the inputs of the output of the first logical element IS-NOT 22, and the outputs of the second 23 and third 24 AND-NOT logic elements are units. In this connection, the controlled switch 14 switches to the position when the latter switches off the output of the speed controller 4 from the driver input of the current regulator 6 and connects this input to the common output point of the control keys 15 and 16. Thanks to the presence of a signal the logical zero at the output of the first logical element IS-NOT 22, the control key 15 enters the state when the voltage from the source J25 of negative polarity goes to the driver input of the current regulator 6 core, converting the thyristor converter 2 to the inverter mode for eff effective resetting of the main current. The drive is effectively slowed down.

When the drive operates in the direction of descent in the regenerative braking mode, a positive polarity signal is present at the output of the speed controller 4, therefore, the first output of the sensing relay element 19

there is a signal of a logical unit, and on the second - zero. Since the corresponding signals are present at the outputs of the sensors 7 and 11 of speed and voltage, the output of the 5 level latch 20 contains a signal of a logical unit, and the output of the logical element 21 is a zero. With such a combination of logical signals at the inputs of the logical elements AND-NOT 22 and 23, a logical unit signal is present at each of their outputs, which leads to the appearance of a logical zero signal at the output of the third logical element AND-NOT 24. The switch-on switch 14 on 5 is in the position when the output of the speed controller 4 is connected to the driver input of the current regulator 6, and the outputs of both the first 15 and second 16 controlled keys are disconnected from sources 25 and 26

0, respectively, of negative and positive reference voltages.

With the disappearance of the feedback signal on speed for the same reasons as in the ascent, the reasons are as follows. The polarity of the signal at the output of the speed controller 4 changes to a negative one, thereby changing the logical state of the outputs of the sensitive relay element 19, a logical zero signal appears at its first output and one at the second output. Since the signal of a logical unit appears at the output of the logical element NOT 21, then at all three inputs of the second logical element, the NAND

5 23 there are single logic signals, while at the first input of the first logical element IS-NOT 22 there is a signal of logical zero. With such a combination of logical signals on

0 inputs at the output of the second logical element AND-NOT 23 a logical zero signal appears, and at the outputs of the first 22 and third 24 AND-NOT logical elements - units. In this connection, the controlled switch 5 switches to the position when the latter switches off the output of the speed controller 4 from the driver input of the current regulator 6 and connects this input to the common output point of the controlled keys 15 and 16.

0 Due to the presence of a logical zero signal at the output of the second logical element IS-NOT 23, the control key 16 enters a state where the voltage from the source 26 of positive polarity arrives at

5 sets the input of the regulator 6 current cor, lock thyristor converter. The drive is effectively slowed down to a stop.

When the drive goes to stop mode, the signal at the output of speed sensor 7 tends to zero even in the absence of faults in the speed feedback circuit. At the same time, the output signal

The voltage sensor 11 is so small that a logic zero signal appears at the output of the level lock 20. Therefore, the output of both the first 22 and the second 23 logical elements AND-NOT contains signals of a logical unit, and the output of the third logical element AND-NOT 24 is zero. Since this mode is not emergency, controlled switch 14, controlled keys 15 and 16 remain in the initial state when the output of the speed controller 4 is connected to the driver input of the current regulator b.

Thus, when the feedback signal disappears in terms of speed, the mode in which this occurred (motor or regenerative braking) is determined, and to localize the emergency situation, either the thyristor converter is converted to an inverter mode or its lock is differentiated.

The proposed scheme of the electric drive, as compared to the known ones, has a higher reliability, since as a result of improving the resolution of the logical part of the device, it is possible not only to fix the fact that the feedback signal on speed disappears, but also the mode (motor or brake) in which it occurred and, depending on the mode, prevent an emergency situation from being differentiated. In addition, improving the resolution of the device eliminates false disconnections of the drive in non-emergency modes.

Claims (1)

Invention Electric drive of a winch, containing an electric motor, the main winding of which is connected to a thyristor converter, in the control circuit of which are connected serially connected speed setting unit and speed controller with limiting unit and current regulator of core with sensors connected to the inputs of the corresponding regulators speed and current core, and the excitation winding of the electric motor is connected to the output of the excitation control system, the inputs of which are connected to the outputs current sensors of the core, voltage on the crust and the excitation current, while the speed sensor is connected to the drum of the winch, so that, in order to increase the reliability of operation of the electric drive due to more precise definition of its mode of operation; a controlled switch, two controlled keys, two modules for selecting a module, a sign-sensitive relay element, a level latch, a logical element NOT, three logical elements NAND and two different polarities are added to it the source of the reference voltage, while the output of the speed regulator is connected to the input of the sensitive sensor relay element, the first output of which is connected to the first input of the first NAND logic element, and the SECOND output -jc to the first input of the second logical th AND-NO element, the sensor output voltage on the bark of through a series-connected first module of module allocation and a level latch connected to the second inputs of the mentioned AND – NES logic gates, the output of the speed sensor through the series-connected the second module of the selection module and the logical element is NOT connected to the third inputs of the said AND NAND logic elements, the output of the first of which is connected to the first input of the third N AND logic element and the control input of the first control key connected between the negative voltage source and the first input of the controlled switch, the output of the second INE logic element is connected to the second input of the third NAND logic element and connected to the control input of the second control key between the source positive reference stress and first the input of the controlled switch, the second input of which is connected with the output of the speed regulator, the output with the master input of the current regulator cor, and the output of the third logical element AND –NE is connected to control input of a controllable switch.