SU1390753A1 - Device for starting multimotor electric drive - Google Patents

Abstract

The invention relates to electrical engineering and can be used in multi-motor electric drives of general industrial mechanisms. The purpose of the invention is to expand the scope. This goal is provided due to the possibility of forming four control signals by means of three electromagnetic relays with windings 1-3, four control buttons 4, 5, 6, 17 connected via diodes 7, 8, 9, 18 to phases 13-15 of power supply 16 and to zero bus 20, respectively. Control signals can be formed in circuits consisting of series-connected make and break contacts of electromagnetic relays. 2 Il.

Description

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The invention relates to electrical engineering and can be used in multi-motor electric drives of general industrial mechanisms.

The purpose of the invention is to expand the scope.

FIG. 1 shows a circuit diagram of the device; in FIG. 2 is one of the possible options for connecting the relay contacts.

The device for starting a multi-motor electric drive contains three electromagnetic relays with windings 1-3, three control buttons 4-6 with a closing contact each and six diodes 7-12, one terminal of the closing contacts of buttons A-6 are combined, another terminal of the closing contact of each button A - 6 controls are connected to the anode, respectively, of the first 7, second 8 and third 9 diodes, the cathodes of which are intended to be connected to the corresponding phases 13-15 of the three-phase power supply 16, the fourth control button 17 with one short circuit the contact, the seventh diode 18 and the resistor 19, one output of the closure of the fourth contact 17 of the control button is connected to the combined outputs of the windings 1-3 of all relays and to one output of the resistor 19, the other output of which is connected to the combined contacts of the same contacts of the first , the second and third control buttons 4 - 6, respectively, another output of the closing contact of the fourth control button 17 is connected to the anode of the seventh diode-18, the cathode of which is connected to the zero bus 20 of the three-phase power supply 16,

The connection diagram of the relay contacts (Fig. 2) contains serially connected closing contacts 21–22, an opening contact 23 of electromagnetic relays with windings 1–3, respectively, successively connected closing contacts 24–26 of electromagnetic relays with windings 2, 3, and 1, respectively. the output of the closing contact 24 is connected to one output of the closing contact 21, the second terminal of which is connected to the series-connected disconnecting contact 27, the closing contact 28 of the electromagnetic relay

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with windings 2 and 3, respectively, the second output of the closing contact 24 through the closing contact 25 with the first output of the opening contact 29.

The device works as follows.

In the initial state, windings 1–3 of all relays are de-energized, relays are disconnected. The first control signal is supplied by pressing the first control button 4. At the same time, the windings 1 and 2 of the first and second relays will be supplied via the following circuits: phase 13 - diode 7 - button 4 - resistor 19 - winding 1 - diode 10 - phase 15 and phase 13 - diode 7 - button 4 - resistor 19 - winding 2 - diode 11 - phase 14. The first and second relays will operate and their contacts 21 and 22 (FIG. 2) will switch control circuits, for example, of a running electric motor or other object. When the controlled object becomes self-powered, the control button 4 can be released. In this case, the windings 1 and 2 of the first and second relays, which are turned off, will lose power, and their contacts will return to their original position.

The second, third and fourth control signals are supplied by pressing the second, third and fourth control buttons 5,6 and 17. In these cases, when the second signal is applied, the first and third relays (windings 1 and 3) will work and contacts 21 and 28 (Fig. 2) will interlock the control circuits of the second object, while the third signal will cause the second and third relays (windings 2 and 3 and contacts 24 and 25), when the fourth signal is applied, all three relays (windings 1 - 3 and contacts 29, 24 and 25. When the control buttons 5,6 and 17 are released, the windings of the relays included in each case will be lost, the relay will also turn off and the device will be ready for the next control signal.

All three relays are selected in such a way that the nominal voltage of their windings 1–3 is equal to the phase voltage of the source 16 of a three-phase alternating current, taking into account the rectification of the current by the diodes. Then when you press the fourth control button 17, the winding of each relay is through

These diodes will be connected between the zero bus 20 and the corresponding phases 13-15 of the source 16 of a three-phase alternating current. When pressing the first, second or third button 4-6 of the control winding of the relay, the corresponding diodes and resistor 19 will be connected in pairs between the corresponding phases 13-15 of the source 16 of the three-phase alternating current. The resistance of the resistor 19 is chosen so that when the total current of two switched on relays through it is, the voltage across it is equal to the difference between the linear and phase voltages of the source 16 of the three-phase alternating current. Diodes 10 - 12 must ensure the flow of current of one relay, diodes 7 - 9 - two relays, and diode 18 - three relays.

Thus, the invention allows to expand the field of application of the device by supplying four control signals using the same number of switching devices and wires.

Claims (1)

Invention Formula A device for starting a multi-motor electric drive containing three electromagnetic relays with windings, three control buttons with a short circuit Each contact and six diodes, one conclusions of the closing contacts of all three control buttons are combined another conclusion of the closing contact of each button and the control are connected to the anode of the first, second and third diodes, respectively, whose cathodes are intended to be connected to the corresponding phases of the three-phase power source, one conclusions windings of all relays are combined, another winding terminal of each relay is connected to the cathode of the fourth, fifth and sixth diodes, respectively, the anodes of which are intended to be connected to The corresponding phases of a three-phase power source, characterized in that, in order to expand the field of application, a fourth control button with one closing contact is introduced into it, the seventh: diode and. a resistor, one output of the closing contact of the fourth control button is connected to the combined winding pins of all relays and one output of a resistor, the other terminal of which is connected to the combined single contacts of the closing contacts of the first, second and third control buttons, another output of the closing contact of the fourth control button connected to the anode of the seventh diode, the cathode of which is connected to the zero width of the three-phase power source.