SU1522301A1 - Device for controlling hoisting electromagnet - Google Patents

Abstract

The invention relates to electrical engineering and can be applied to control a lifting electromagnet. The aim of the invention is to increase labor productivity by reducing the time to which the current drops when the electromagnet is turned off. In the magnetizing mode, the on-off key 9 is in the position where contacts 10 and 11 are closed. In this case, the control electrodes and the anodes of the thyristors of the magnetization group 2 are energized simultaneously. When key 9 is reversed to the opposite position, the magnetization group 2 is transferred to the inverter mode, which accelerates the recovery of the energy accumulated in the winding. 2 Il.

Description

The invention relates to electrical engineering and can be applied for the control of a lifting electromagnet, with

The purpose of the invention is to increase productivity by reducing the current decay belt when the lifting electromagnet is disconnected.

Figure 1 is a diagram of a device for controlling a lifting electromagnet; Fig. 2 shows the malicious diagrams characterizing the operation of the device.

The device includes a three-phase j transformer 1, a reversible controlled transducer, including a magnetization group 2, made in the form of a three-phase thyristor converter assembled according to zero 20 circuit, a demagnetization group 3, having two thyristors and made in the form of a three-phase two-period rectifier, winding an electrometer. one pin-5 of which is connected to the 25th output of the reversible controlled converter, and the second pin 6 is connected to the zero output of the secondary winding of the transformer, protective diodes 7, block 8 controls, containing a two-position key 9, having four moving 10 contacts, four: fixed 11 in the first position and three fixed contacts 12 in the second position, a single-phase bridge rectifier 13, a relay having a winding 14, four closing contacts 15 and an open repentant contact. 16, a relay having a winding 17 and a closing contact 18 with an open time delay, three resistors 19.

In the magnetizing mode, the on-off control key 9 is in the first position (position H), on the control electrodes and anodes of the thyristor;

The magnetization group stator is energized simultaneously and the power current flows excluding the switching times of the thyristors through a single phase transformer winding,

one thyristor of magnetization group, electromagnet winding, zero output of the secondary winding of the transformer. In the H position of the control key 9, the windings of the relays 14 and 17 are powered, while the contacts 15 are closed, the contact 16 is open, the contact 18 is closed.

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When translating key 9 at time t (figure 2) to the second position

, (position P), the control electrodes of the thyristors of the magnetization group begin to receive control voltage from the subsequent phase of the secondary winding of the transformer through closed contacts 15 and resistors 19. The control voltage is shifted from the natural switching point of the thyristors by an angle of 7 60 (Fig .2). The magnitude of the angle d is determined by the magnitude of the resistance of the resistors 19. To provide an inverter mode with the help of resistors 19, the angle is in the range of 120 - / 150. Switching of the thyristors of the magnetization group occurs alternately after 120 ..

After the electromagnet winding with the help of the magnetizing grooves. operating in the inverter mode, and the transformer transfers the stored electromagnetic energy to the network, the current through it stops, the voltage on the electromagnet winding drops to zero. Winding relay 14 and relay 17

The power is lost, the contacts 15 are opened, the thyristors of the magnetization group are disconnected, and the relays 14, 17 are removed from self-pickup, the contact 16 is closed, and the contact 18 remains closed for the length of time set for the relay 17. A control voltage is applied to the control electrodes of the two thyristors of the demagnetization group, the thyristors are opened, through the electromagnet, the current flows in the opposite direction, and the electromagnet is demagnetized. After the set time delay has elapsed, contact 18 is opened, the control signal to the control electrodes of the thyristors of the demagnetization group is not received, the current through the thyristors and the electromagnet winding is stopped. A short-term current flow through the winding of the electromagnet in the opposite direction allows the residual magnetization of the lifting electromagnet to be removed.

Switching the magnetization group of the converter to the inverter mode allows to accelerate the recovery of energy stored in the winding of the electromagnet, to increase the performance of the lifting electromagnet.

Claims (1)

Invention Formula A device for controlling a load-lifting electromagnet containing a reversible controllable converter that is connected to the secondary winding of a three-phase transformer, the primary winding of which is connected to a power source having a magnetization group, executed in a track-phase thyristor converter assembled in zero a circuit whose output is connected to the first terminal for connecting the winding of the electromagnet, the second terminal for connecting which is connected to the zero terminal of the secondary winding of the transformer , and a demagnetization group, having two thyristors, the cathode of each of which is connected to one of the phases of the secondary winding of a three-phase transformer, and the anodes are combined at a common point and connected to the first terminal for connecting the electromagnet winding, protective discs by the number of thyristors, the cathodes of which are connected to thyristor control electrodes, a control unit including a control switch, characterized in that, in order to increase device performance by shortening the current dropping time when the winding is disconnected magnet, in the control unit entered the first electromagnetic relay with four closing and one normally open contacts, the second electromagnetic relay with one closing contact having a time delay to open, single-phase bridge 0 five five 0 five a rectifier, three resistors, a two-position key with four fixed contacts of the first key position, three fixed contacts of the second key position and four movable contacts, the first movable con; clock connected to a single input of a single-phase bridge was used as a control key The output windings of the first and second relays are connected to the output of which, and the second input of the single-phase bridge top is connected to the first output of the winding by an electric plug, the second fixed is connected to the second output. the contact of the first control key position, parallel to the first movable and fixed contacts of the control key, is a short-circuited contact of the first relay, three other movable contacts of the control key are connected to the anodes of three protective diodes of the magnetization group, three fixed contacts of the first position of the control key are connected to the corresponding phases of the secondary winding transformer, and each of the three other fixed contacts of the second position of the control key is connected to the subsequent phase of the secondary winding of the transformer torus through the resistor and the closing contact of the first relay, the anodes of the protective diodes of the demagnetization group are combined into a common point and sub-. united to the first output of the electromagnet winding through a series-connected disconnecting contact of the first relay and the contact of the second relay closing with time delay for opening. 150 FIG. 2