RU2118866C1 - Control device for reversing electromagnetic contactor - Google Patents

Abstract

FIELD: electrical engineering. SUBSTANCE: device has two leads for connecting power supply, STOP control button connected between first power lead and parallel circuit set up of series-connected FORWARD (REVERSE) contactor coil, auxiliary break contact of REVERSE (FORWARD) contactor, and START 1 (START 2) button; common points of contactor coils are connected to second power lead; auxiliary make contacts of FORWARD and REVERSE contactors shorting out START 1 and START 2 buttons, respectively, are connected through first terminals to common point of connection of STOP, START 1, and START 2 buttons; in addition, device is provided with current-limiting member one of whose leads is connected to terminals of START 1 button and make contact of auxiliary circuit of REVERSE contactor and other lead, to terminals of START 2 button and break contact of auxiliary circuit of REVERSE contactor; second terminals of auxiliary make contacts of FORWARD and REVERSE contactors are connected, respectively, to common point of connection of START 2 button and auxiliary break contact of FORWARD contactor and to that of START 1 button and auxiliary break contact of REVERSE contactor. EFFECT: reduced power requirement and material input. 2 dwg

Description

 The present invention relates to electrical engineering, namely to low-voltage apparatus engineering, and can be used in low-voltage complete devices (NKU) and control stations using reversible electromagnetic contactors.

 Known control devices for a reversible electromagnetic contactor (starter) used to start, reverse, stop an asynchronous motor with a squirrel-cage rotor (for example, see TU16-89 IGFR. 644236.033TU, p. 135, Fig. 22), in which the reversible contactor is controlled from the same AC network, from which the electric motor controlled by the reversing contactor is powered, i.e. The reversing contactor is made with AC electromagnets. In these devices, the control buttons are used to control the reversing contactor (starter): Stop, connected in series with an electric circuit that includes two circuits connected in parallel: the Start 1 control button, shunted by the make contact of the auxiliary circuit of the Forward contactor and connected to the opening contact of the auxiliary circuit of the contactor "Back", connected to the switching coil of the contactor "Forward", and the control button "Start 2", shunted by the closing contact of the auxiliary contactor circuit "Back" and connected to the opening contact of the auxiliary circuit of the contactor "Forward", in turn connected to the switching coil of the contactor "Back".

 The disadvantage of these control devices is the relatively low reliability in operation, determined mainly by the low reliability characteristic of AC electromagnets (loss and breakage of short-circuited turns, fluffing of charged magnetic systems, relatively low wear resistance, etc.).

 Therefore, in an industry with increased requirements for the reliability of the operation of electrical equipment, electromagnetic devices (contactors, starters, relays) with direct current control that do not have these drawbacks are mainly used. For example, in metallurgy, characterized by heavy duty, for controlling asynchronous motors with both a squirrel-cage rotor and a phase rotor, reversible AC contactors of types MK1-30 and MK2-30 are widely used (for rated currents of 40 and 63 A, respectively) . For reversing DC motors, DC contactors of types MK1-20, MK2-20, MK3-20 and MK4-20 are also widely used. In this case, the control device of the reversing contactor is completely identical to the above, except for the type of current of the control circuit, i.e. in this case, the entire control circuit is connected to a DC power source, independent of the main circuit power source - the electric motor circuit (Electromagnetic starters PML TU16-91 IHEV.644131.001TU, fig. 16, p. 120).

 In the drawing of FIG. 1 is a diagram of a control device for a reversible electromagnetic contactor with a direct current coil, i.e. with a direct current control circuit.

 As can be seen from FIG. 1, the known device adopted for the prototype, contains conclusions 1 and 2 for connecting a power source, in this case, a constant current source. The rest of the control circuit contains the same elements as the device, taken as an analogue.

 In the known device, the second terminals of the make contacts of the auxiliary circuits of the Forward and Back contactors are connected respectively to the common connection point of the terminals of the Start 1 control button and the NC contact of the auxiliary circuit of the Back contactor; and to the common connection point of the terminals of the Start 2 control button and the normally open contact of the auxiliary circuit of the Forward contactor directly. That is, the control buttons "Start 1" and "Start 2" are bridged directly by the closing contacts of the auxiliary circuits of the contactors "Forward" and "Back", respectively.

 However, despite the increased reliability compared to the first case, the control device also has disadvantages, namely, the increased power consumption of the electromagnets of the reversing contactor in the holding mode, the overspending of the winding copper of the electromagnets.

 The technical result of the invention is to reduce power consumption and save materials (winding copper) of the device.

 The technical result is achieved by the fact that the control device is a reversible electromagnetic contactor, containing two terminals for connecting a power source, a Stop control button connected between the first terminal for connecting a power source and a parallel circuit, consisting respectively of series-connected windings of the Forward contactor, opening the contact of the auxiliary circuit of the contactor “Back”, the control button “Start 1” and the windings of the contactor “Back”, the opening contact of the auxiliary circuit of the contactor and "Forward," control buttons "Start 2"; moreover, the common points of the contactor windings are connected to the second terminal for connecting the power source, and to the common connection point of the Stop, Start 1, Start 2 control buttons, the first terminals are connected by the closing contacts of the auxiliary circuits of the Forward and Back contactors, is additionally equipped with a current-limiting element, one output of which is connected to a common connection point of the terminals of the Start 1 control button and an NC contact of the auxiliary circuit of the Back contactor, and the other to a common connection point of the control button terminals "Start 2" and the NC contact of the auxiliary circuit of the contactor "Forward", and the second terminals of the NO contacts of the auxiliary circuits of the contactors "Forward" and "Back" are connected to the common connection point, respectively, of the control button "Start 1", the NC contact of the auxiliary circuit of the contactor "Back" and the Start 2 control button, the opening contact of the auxiliary circuit of the Forward contactor through the current-limiting element.

 The essence of the invention lies in the fact that the additional supply of a known reversible electromagnetic contactor control device with a current-limiting element, one output of which is connected to the common connection point of the terminals of the Start 1 control button and the NC contact of the auxiliary circuit of the Back contactor, and the other to the common connection point terminals of the Start 2 control button and the auxiliary contact of the auxiliary contactor circuit "Forward", and the second terminals of the auxiliary contacts of the auxiliary contactor circuit "Forward" and “Back” are connected to a common connection point, respectively, of the “Start 1” control button, the NC contact of the auxiliary contactor circuit “Back” and the control button “Start 2”, the NC contact of the auxiliary circuit of the contactor “Forward” through the current-limiting element, allowed to reduce the power consumption of the reverse electromagnetic apparatus by reducing the current in the coil circuit in the on mode, to obtain winding copper savings, reduce the mass of the apparatus and its dimensions by reducing the number of turns of the coils.

 In FIG. 2 shows a diagram of the proposed control device. As can be seen from FIG. 2, it contains terminals 1 and 2, current-limiting element 3, control buttons "Start 1", "Start 2", "Stop", including coils B, H of the contactors "Forward" and "Back", connected in series with the buttons "Start 1 "and" Start 2 "through the opening contacts of the auxiliary circuit of the contactors" Back "and" Forward ", respectively.

 The proposed device operates as follows. To start the engine in one of the directions, for example, “Forward”, the operator must press the “Start 1” button. At the same time, the Forward contactor coil B is connected to the full voltage of the power supply and draws current through the circuit: terminal 1, contacts of the Stop, Start 1 control buttons, opening contact of the back contactor auxiliary circuit, through the B coil, terminal 2 The “Forward” contactor opens the auxiliary contact B of the auxiliary circuit and interrupts the flow of small current through the coil H, limited by the total resistance of the current-limiting element 3 and the winding H; closes its main contacts included in the electric motor circuit (not shown in Fig. 2), and then the closing contact B of its auxiliary circuit. When you release the "Start 1" button, the coil B of the "Forward" contactor does not turn off, because it will be powered by the circuit: terminal 1, the Stop control button, closed contact B of the auxiliary circuit of the Forward contactor, current limiting element 3, NC contact H of the auxiliary circuit of the Back contactor, coil B and terminal 2.

 At the initial moment, the current in the circuit of coil B is limited only by its resistance. After switching on the contactor and opening the contact of the Start 1 control button, the current in the coil circuit B will also be limited by the current-limiting element additionally introduced into the coil circuit. This reduces the power consumed by the coil, and therefore the contactor itself in the on state. As a current-limiting element, a resistor or series-connected holding windings of contactor coils, one of the holding windings, etc. can be used.

 Since in the holding mode when the anchor is pulled in, large MDS is not required, this introduction of a current-limiting element also reduces the number of turns of coils, which means that copper consumption and the weight of the apparatus are reduced.

 To start the engine in a different direction, i.e. reversing the engine, you must press the "Stop" control button. In this case, the Forward contactor coil B loses power, opens its make contact B of the auxiliary contactor circuit, and makes the make contact of B auxiliary contactor circuit included in the back contactor coil H, in preparation for switching it on. Then you need to press the "Start 2" control button. In this case, everything will be repeated in the same sequence as when starting in the "Forward" direction, but only the rotation of the motor will occur in the opposite direction (due to the change of phase rotation or the direction of current flow in the stator winding of the DC motor - in Fig. 2 not shown). At the initial moment, the “Back” contactor coil will receive power through the circuit: terminal 1, “Stop” control button, “Start 2” control button, NC contact B of the auxiliary contactor circuit “Forward”, coil H, terminal 2. Then, also in the same circuit the current limiting element 3 is introduced to the coil, and the coil H receives power through the circuit: terminal 1, the Stop control button, the closed make contact H of the auxiliary circuit of the contactor "Back", the current limiting element 3, the closed normally closed contact B of the auxiliary circuit of the contactor "Forward", coil H terminal 2.

 Therefore, the introduction in a certain way of the current-limiting element in the known device allows to save on copper, electricity, reduce the mass and material consumption of the apparatus.

Claims (1)

 A control device for a reversible electromagnetic contactor, containing two terminals for connecting a power source, a Stop control button connected between the first terminal for connecting a power source and a parallel circuit, consisting respectively of series-connected windings of the Forward contactor, the opening contact of the auxiliary circuit of the Contactor back ", the control buttons" Start 1 "and the windings of the contactor" Back ", the opening contact of the auxiliary circuit of the contactor" Forward ", the control buttons" Start 2 ", and common points of the contactor windings are connected to the second terminal for connecting the power source, and to the common connection point of the Stop, Start 1, and Start 2 control buttons, the first terminals are connected by the closing contacts of the auxiliary circuits of the Forward and Back contactors, which differs the fact that it is additionally equipped with a current-limiting element, one output of which is connected to the common connection point of the terminals of the Start 1 control button and the NC contact of the auxiliary circuit of the Back contactor, and the other to the common connection point of the terminals to the control buttons "Start 2" and the NC contact of the auxiliary circuit of the contactor "Forward", and the second terminals of the NO contacts of the auxiliary circuits of the contactors "Forward" and "Back" are connected to the common connection point, respectively, of the control button "Start 1", the NC contact of the auxiliary circuit of the contactor " Back "and the Start 2 control button, the opening contact of the auxiliary circuit of the Forward contactor through a current-limiting element.

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