JP2009158159A - Electromagnetic coil driving circuit of electromagnetic contactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic coil driving circuit of an electromagnetic contactor capable of surely carrying out opening and closing operation of the main contact even while suppressing consumption of electric power. <P>SOLUTION: This is the electromagnetic coil driving circuit 100 which is made to have a circuit constitution in which by operating a switching circuit 110 on the condition that an auxiliary contact SW being an operation switch is switched from an open state to a closed state, and then by switching a semiconductor switching element MOSFET 4 which is in an ON state of closing a bypass line L2 to an OFF state of opening the bypass line L2, an energization pattern is switched from a first energization pattern in which an excitation current is supplied only to a pick-up coil 37 to a second energization pattern in which the excitation current is supplied to both of the pick-up coil 37 and a hold coil 36. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electromagnetic coil drive circuit for an electromagnetic contactor.

  Conventionally, a fixed iron core formed by winding an exciting electromagnetic coil, a movable iron core, an urging means for applying an urging force in a separating direction between the two iron cores, and an electromagnetic having a main contact made up of a fixed contact and a movable contact Contactors are known. In this case, when the electromagnetic coil is energized, a magnetic attraction force acts between the two iron cores, and the movable iron core that is in the contact / separation state is attracted to the fixed iron core. The movable contact of the electromagnetic contactor is configured to be displaced integrally with the movable iron core, and as a result of the movable contact moving relative to the fixed contact in conjunction with the pulling of the iron core, the main contact is closed from the open state, Or it has composition which changes from a closed state to an open state.

  And even after the movable iron core is drawn into the fixed iron core, it can be held in the drawn-in state by continuously energizing the electromagnetic coil and applying a magnetic attractive force between the two iron cores. Can be maintained (hold operation).

  Such a hold operation may be a magnetic attraction force weaker than that of a pickup operation that pulls in the movable iron core, and can suppress an energization amount (excitation current supply amount) to the electromagnetic coil. Therefore, as described in Patent Document 1 below, as an electromagnetic coil for excitation, a pickup coil and a hold coil are provided exclusively, and by switching the coil to be used according to the operation, power consumption can be reduced. There are attempts to suppress it.

In addition, the electromagnetic contactor generally includes an auxiliary contact having a smaller current capacity than the main contact in addition to the main contact constituted by the fixed contact and the movable contact. The auxiliary contact is mechanically linked to the main contact. For example, when the main circuit is opened / closed by the main contact, the auxiliary contact is used for the purpose of opening / closing the signal line and linking with other circuits. It may also be used as a switching circuit that switches between a pickup operation and a hold operation.
JP 2005-235515 A

  By the way, as shown in FIG. 7, the above-mentioned main contact and auxiliary contact are normally closed type (normally closed) in which the contacts (the fixed contact 351 and the movable contact 353) come into contact with each other in the non-energized state. 8 and a normally open type (normally open) type in which the contacts (the fixed contact 351 and the movable contact 353) are separated and open in a non-energized state as shown in FIG.

Here, when the electromagnetic coil is energized and the movable iron piece 320 is drawn into the fixed iron core 310, the normally closed contact is switched from the closed state to the open state at the initial stage of drawing as shown in FIG. For this reason, if a switching circuit is configured using a normally closed auxiliary contact, the switching circuit operates at the initial stage of pull-in, and the pickup operation with a strong magnetic attractive force shifts to a holding operation with a low magnetic attractive force. . In order to more reliably open and close the main contact of the electric contactor, it is preferable to apply a strong magnetic attraction force during the pull-in operation and shift to a hold operation with a weak magnetic attraction force after the pull-in is completed. It was necessary to set the operation timing to the optimum timing.
The present invention has been completed based on the above situation, and provides an electromagnetic coil drive circuit for an electromagnetic contactor capable of more reliably opening and closing a main contact while suppressing power consumption. The purpose is to do.

  The present invention is an electromagnetic coil drive circuit of an electromagnetic contactor comprising a main contact that opens and closes by energizing an electromagnetic coil for excitation, and an auxiliary contact that opens and closes mechanically linked to the main contact. A pickup coil having one end connected to the ground, a hold coil connected in series to the pickup coil and constituting the electromagnetic coil together with the pickup coil, and an excitation current supplied to the electromagnetic coil drawn from a power source A power supply line that connects the two ends of the hold coil to each other, bypasses an excitation current supplied through the power supply line, bypasses the hold coil, and flows only to the pickup coil, and excitation supplied through the power supply line A first energization pattern for supplying current only to the pickup coil; A switching circuit for switching to a second energization pattern to be supplied to both the pickup coil and the hold coil, and among the auxiliary contacts, the contact point when no excitation current is supplied to the electromagnetic coil When a normally closed auxiliary contact that contacts each other and closes is defined as a normally closed contact, and a normally opened auxiliary contact that opens when the contacts are separated from each other when not energized is defined as a normally open contact, The switching circuit includes at least a semiconductor switching element provided in the bypass line and an operation switch including a normally open contact type auxiliary contact, and the auxiliary contact that is the operation switch is switched from an open state to a closed state. The semiconductor in an on state in which the circuit is operated to a condition and the bypass line is closed By switching element is switched to the off state to open said bypass line has a feature where there as a circuit configuration in which energization pattern is switched to the second energization pattern from the first energization pattern.

  The present invention is an electromagnetic coil drive circuit of an electromagnetic contactor comprising a main contact that opens and closes by energizing an electromagnetic coil for excitation, and an auxiliary contact that opens and closes mechanically linked to the main contact. A hold coil having one end connected to the ground and the other end connected to a power supply line, a pickup coil connected in parallel to the hold coil and constituting the electromagnetic coil together with the hold coil, and through the power supply line A switching circuit for switching between a first energization pattern that supplies the excitation current to be supplied to both the pickup coil and the hold coil and a second energization pattern that is supplied only to the hold coil; Among the auxiliary contacts, the contacts are in contact with each other when no excitation current is supplied to the electromagnetic coil. When the normally closed auxiliary contact that is in a state is defined as a normally closed contact, and the normally open auxiliary contact that is in an open state when the contacts are separated when not energized is defined as a normally open contact, the switching circuit is A semiconductor switching element provided in a parallel line for connecting a pickup coil in parallel with the hold coil; and at least an operation switch formed of a normally open contact type auxiliary contact, wherein the auxiliary contact is the operation switch. The circuit is activated on the condition that the open state is switched to the closed state, and the semiconductor switching element in the on state that closes the parallel line is switched to the off state that opens the parallel line, whereby the first energization is performed. A circuit configuration in which the energization pattern is switched from the pattern to the second energization pattern; It has a feature where there is Te.

The following configuration is preferable as an embodiment of the above invention.
The switching circuit includes a P-channel field effect transistor as a semiconductor switching element having a source connected to the power supply side and a drain connected to the pickup coil side on the bypass line or the parallel line, and a source on the ground side And an N-channel field effect transistor having a drain connected to the gate of the P-channel field effect transistor, and the gate of the N-channel field effect transistor is connected to the power supply side via a current limiting resistor Then, the potential of the gate is set to H level, and the end of the current limiting resistor on the side connected to the gate of the N-channel field effect transistor is connected to the ground by the normally open contact type auxiliary contact. The circuit configuration is connected to In this way, the switching circuit can be configured with a relatively simple circuit configuration.

  According to the present invention, the operation switch of the switching circuit is constituted by the auxiliary contact of the normally open contact. Accordingly, since the switching circuit operation timing, that is, the switching timing of the energization pattern is an appropriate timing (the completion stage of the pull-in operation), it is possible to reliably switch the main contact from the open state to the closed state. Increased reliability in operation.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the electromagnetic contactor 10 is configured such that a fixed iron core 30, a movable iron core 40, and a main contact 51 are stacked in a casing 20 from below.

  To explain step by step, the casing 20 has a base portion 21 at the bottom and is generally box-shaped. A contact housing part 23 is provided in the center of the casing 20, and a shaft hole 25 is formed so as to penetrate the contact housing part 23 vertically. The shaft hole 25 of the casing 20 is formed in a step shape, the shaft hole upper part 26 has a small hole diameter, and the shaft hole lower part 27 has a large hole diameter.

  A fixed contact 53 including a pair of fixed terminals 53 a and 53 b and a movable contact 55 that constitutes the main contact 51 together with the fixed contact 53 are disposed in the contact accommodating portion 23. The fixed terminals 53 a and 53 b are arranged on the left and right sides of the shaft hole 25 on the lower side of the contact accommodating portion 23.

  The movable contact 55 has a flat plate shape, and is supported on the upper side of the fixed contact 53 so as to be vertically movable by a terminal holder 43 described later. On the lower surface of the movable contact 55, movable terminals 55a and 55b are respectively arranged at both left and right ends. The movable terminals 55a and 55b are counterparts to the fixed terminals 53a and 53b.

  The fixed iron core 30 has a cylindrical shape, and is disposed at the center of the base portion 21 and immediately below the shaft hole 25. An electromagnetic coil 35 is wound around the outer periphery of the fixed iron core 30. As will be described in detail later, the electromagnetic coil 35 includes two types of coils: a hold coil 36 having a large coil resistance and a pickup coil 37 having a small coil resistance.

  The movable iron core 40 has a columnar shape with substantially the same diameter as the fixed iron core 30. The movable iron core 40 is accommodated in a shaft hole lower portion 27 provided in the casing 20 and is configured to face the fixed iron core 30 vertically.

  Further, the movable iron core 40 is provided with a contact holder 43 at the top. The contact holder 43 includes a fixed portion 44 fixed to the movable iron core 40 and a cross bar 45 formed integrally with the center of the upper surface of the fixed portion 44 and vertically passing through the shaft hole 25 of the casing 20.

  The cross bar 45 supports the movable contact 55 described above so as to be movable up and down, and includes a contact insertion groove 46 through which the movable contact 55 is horizontally inserted at the center in the longitudinal direction. A pressure spring 48 is accommodated in the contact insertion groove 46, and the movable contact 55 inserted in the contact insertion groove 46 is urged downward.

  A biasing coil spring 60 is disposed between the movable iron core 40 and the coil case 35 </ b> A of the electromagnetic coil 35. Thereby, the movable iron core 40 and the contact holder 43 are configured to be constantly pushed upward (in the direction away from the fixed iron core 30) by receiving the biasing force of the coil spring 60.

  From the above, the electromagnetic contactor 10 is in a state where the movable contact 55 is separated from the fixed contact 53 as shown in FIG. The main contact 51 is in an open state.

  In addition, the electromagnetic contactor 10 is provided with an auxiliary contact SW. The auxiliary contact SW is provided with a movable contact and a fixed contact in the same manner as the main contact 51 described above, and the movable contact is mechanically interlocked with the movable contact on the main contact 51 side to pull in the movable iron core 40. The opening / closing operation is performed together with the opening / closing operation of the main contact 51 involved. Then, a normally closed auxiliary contact (hereinafter referred to as a normally closed contact) that contacts and closes when the electromagnetic coil 35 is not energized and is closed, and a contact that is separated when not energized. There are two types of normally open auxiliary contacts (normally open contacts) that are open, and this magnetic contactor 10 also comes with two types of auxiliary contacts SW: normally closed contacts and normally open contacts. Yes.

Next, a specific circuit configuration of the electromagnetic coil driving circuit 100 will be described with reference to FIG.
In the figure, reference numeral 36 denotes a hold coil, and reference numeral 37 denotes a pickup coil that constitutes an electromagnetic coil 35 together with the hold coil 36. The hold coil 36 of the present embodiment has a large coil resistance, and the pickup coil 37 has a small coil resistance.

  The hold coil 36 and the pickup coil 37 are connected in series, and one end of the pickup coil 37 is connected to the ground GND.

  On the other hand, one end of the hold coil 36 is connected to a power supply line L1 connected to the power supply V. The power supply line L1 is provided with a load switch composed of a P-channel field effect transistor MOSFET1 so that the line is opened and closed.

  In the field effect transistor MOSFET1, the source S is connected to the power supply V, the drain D is connected to the coil side, and the gate is connected to the drain D of the N-channel field effect transistor MOSFET2 via the resistor R1. The resistor R1 has a function of suppressing surge absorption and parasitic vibration.

  The field effect transistor MOSFET2 is for driving the gate G of the field effect transistor MOSFET1, the source S is connected to the ground GND, and a control signal (H level) is connected to the gate G through a control circuit (CPU or the like) not shown. / L level binary signal) Sr is input.

  A gate bias resistor R2 is connected between the gate G and the source S of the field effect transistor MOSTFET1, and a gate bias resistor R3 is connected between the gate G and the source S of the field effect transistor MOSTET2. Both of these resistors R2 and R3 function as a discharge resistor that discharges charges accumulated in the parasitic capacitance between the gate and the source, and contribute to stable operation of the circuit.

  The electromagnetic coil drive circuit 100 is provided with a switching circuit 110 including a field effect transistor MOSFET3, a field effect transistor MOSFET4, a resistance pair R6, R7, an auxiliary contact SW, and the like.

  If it demonstrates sequentially, the bypass line L2 is provided so that the coil both ends of the hold coil 36 may be connected mutually. The bypass line L2 is provided with a P-channel field effect transistor MOSFET3. The field effect transistor MOSFET 3 corresponds to the “semiconductor switching element (P channel type field effect transistor)” of the present invention, and the source S is connected to the drain D of the field effect transistor MOSFET 1 and the drain D is connected between the coils. Connected to an intermediate connection point C.

  A resistor R4 is connected between the gate G and the source S of the field effect transistor MOSFET 3, and the gate G of the MOSFET 3 is connected to the drain D of the N-channel field effect transistor MOSFET 4 through the resistor R5. . The field effect transistor MOSFET 4 corresponds to the “N-channel field effect transistor” of the present invention, and the source S is connected to the ground GND.

  The gate G of the field effect transistor MOSFET 4 is connected to the drain D of the field effect transistor MOSFET 1 by a connection line L3 including a resistance pair formed by connecting two resistors R6 and R7 in series. A resistor R8 is connected between the gate G and the source S of the transistor MOSFET4.

  With the above configuration, the gate of the N-channel field effect transistor (here, the MOSFET 4) is connected to the power source side (here, the field effect transistor MOSFET1) via a current limiting resistor (here, the resistor R7). The potential of the gate is set to the H level by connecting to the drain D).

  An intermediate connection point K between the resistors R6 and R7 is connected to the ground GND by a normally open contact type auxiliary contact SW. The normally open contact type auxiliary contact SW functions as an operation switch for operating the switching circuit 110.

  The reason why the resistor R7 is included on the connection line L3 on the side closer to the power source V when viewed from the auxiliary contact SW is to cause the resistor R7 to function as a current limiting resistor. Largely set. With such a configuration, when the auxiliary contact SW is in the closed state, the current value of the current L3 flowing through the connection line L3 can be reduced, which is effective for power saving of the circuit (see FIG. 4).

Next, the circuit operation of the above-described electromagnetic coil drive circuit 100 will be described.
In a state where an L level signal is output as a control signal Sr from a control device such as a CPU, Vgs (potential difference between the gate and the source with reference to the source S side) of the field effect transistor MOSFET2 is substantially zero. Therefore, it is turned off.

  Then, since the potential of the gate G of the MOSFET 1 becomes substantially equal to the potential of the power supply V, the field effect transistor MOSFET 1 becomes almost zero because Vgs becomes almost zero. As a result, the power supply line L1 is opened.

  From the above, during the period when the gate G of the field effect transistor MOSFET2 is at the L level, the exciting current is not supplied to the electromagnetic coil 35, and the movable iron core 40 constituting the electromagnetic contactor 10 is shown in FIG. It will be in the state spaced apart from the fixed iron core 30 as shown by. Therefore, the fixed contact 53 and the movable contact 55 are separated from each other, and the main contact 51 is kept open.

  In order to switch the main contact 51 in the open state to the closed state, an H level signal may be input to the gate G of the field effect transistor MOSFET 2 as the control signal Sr. When an H level signal is input, first, Vgs becomes a predetermined positive voltage, and the field effect transistor MOSFET2 is turned on from the off state.

  Then, a current flows through the resistor R2, the resistor R1, and the MOSFET 2, and a voltage drop occurs in the resistor R2. Therefore, Vgs becomes a predetermined negative voltage and the field effect transistor MOSFET1 is turned on, so that the power supply line L1 is closed.

  On the other hand, the auxiliary contact SW constituting the switching circuit 110 is a normally open contact, and is in an open state immediately after an H level signal is input as the control signal Sr to the gate G of the field effect transistor MOSFET2.

  Accordingly, the gate G of the field effect transistor FET4 constituting the switching circuit 110 is connected to the power supply side via the resistor pair R6 and R7, and the potential of the gate G becomes H level. Therefore, the field effect transistor FET4 is turned on because Vgs is a predetermined positive voltage.

  When the field effect transistor MOSFET4 is turned on, a current flows through the resistor R4, the resistor R5, and the MOSFET 4, and a voltage drop occurs in the resistor R4. Therefore, Vgs becomes a predetermined negative voltage and the field effect transistor MOSFET3 is turned on. As a result, the bypass line L2 is closed.

  From the above, immediately after the H level signal is input as the control signal Sr to the gate G of the field effect transistor MOSFET2, the exciting current flows through the path of the power supply line L1 and the bypass line L2 as shown by the solid line in FIG. The excitation current is supplied only to the pickup coil 37 (first energization pattern).

  Since the pickup coil 37 has a small coil resistance and a large excitation current flows, a strong magnetic attraction force is generated between both the iron cores 30 and 40, and the movable iron core 40 in the separated state shown in FIG. It is pulled toward the fixed iron core 30 (retraction operation). As a result, when the contact holder 43 is pulled, the movable contact 55 supported by the contact holder 43 moves closer to the fixed contact 53.

  At this time, since the auxiliary contact SW is also mechanically interlocked with the main contact 51, the movable contact (not shown) of the auxiliary contact SW moves closer to the fixed contact (not shown) of the auxiliary contact SW.

  When the movable iron core 40 is drawn until the movement amount reaches the specified value A, the iron cores 30 and 40 are in contact with each other as shown in FIG. At this time, the movable terminals 55a and 55b of the movable contact 55 are in contact with the fixed terminals 53a and 53b of the fixed contact 53, respectively. Thus, the main contact 51 that is open in the non-energized state is closed.

  When the main contact 51 is in a closed state, the auxiliary contact SW that operates mechanically in conjunction with the main contact 51 is also in a state in which the movable contact and the fixed contact are in contact with each other, as shown in FIG. Become.

  Thus, when the auxiliary contact SW that has been in the open state immediately after the H level signal is input is in the closed state, each FET constituting the switching circuit 110 is activated by using this as a trigger, and the energization pattern for the electromagnetic coil 35 is changed to the pickup coil 37. The first energization pattern for supplying the excitation current only to the second energization pattern is switched from the first energization pattern for supplying the excitation current to both the hold coil 36 and the pickup coil 37.

  Specifically, referring to FIG. 4, when the auxiliary contact SW is switched from the open state to the closed state, the field effect transistor MOSFET4 is in a state where the gate G is grounded to the ground by the auxiliary contact SW. It becomes almost zero and is turned off. As a result, the field effect transistor MOSFET3 becomes almost zero and Vgs is turned off, and as a result, the bypass line L2 is opened (open circuit). Therefore, as indicated by a one-dot chain line in FIG. 4, an excitation current is supplied to both the hold coil 36 and the pickup coil 37 through the power supply line L1 (second energization pattern).

  From the above, the hold coil 36 and the pickup coil 37 are excited, and a magnetic attraction force is generated between the fixed iron core 30 and the movable iron core 40 to maintain the contact state of both iron cores. It will be held (hold operation). As a result, the main contact 51 is maintained in the closed state.

  Here, since the coil resistance of the hold coil 36 is set to be large, the magnitude of the exciting current flowing in the second energization pattern is smaller than that of the first energization pattern, and the degree of magnetism necessary for performing the hold operation. Only suction force is generated.

  That is, in the present embodiment, two kinds of energization patterns are provided, and during the pulling operation, a large excitation current is supplied from the power source V to the electromagnetic coil 35 to pull in the movable iron core 40 with a strong magnetic attraction force, while during holding The power consumption of the circuit can be suppressed by suppressing the magnitude of the excitation current to a level necessary to maintain the hold state.

  Further, according to the electromagnetic coil drive circuit 100 of the present embodiment, the switching of the energization pattern is performed by the switching circuit 110. The switching circuit 110 is an auxiliary switch for a normally open contact as an operation switch for operating the circuit. A circuit is configured using the contact SW.

  If it is a normally open contact, it remains in the open state at the initial stage of retraction, and is retracted until the movable iron core 40 comes into contact with the fixed iron core 30 (retraction operation is completed). It will be.

  Therefore, the switching circuit 110 is activated after the movable core 40 is pulled in until the movable core 40 comes into contact with the fixed core 30 (after the pull-in operation is completed), inevitably from the first energization pattern to the second energization pattern. The switching is also performed when the movable iron core 40 is pulled in until it comes into contact with the fixed iron core 30.

  Therefore, a strong magnetic attraction force is always applied between the iron cores 30 and 40 during the retraction operation, and the movable iron core 40 can be reliably retracted until it comes into contact with the fixed iron core 30.

  Here, assuming that a normally closed contact is used as the operation switch, the movable contact 353 is originally in contact with the fixed contact 351 as described with reference to FIGS. However, when it is displaced in the separating direction, it is separated from the fixed contact 351. As a result, the auxiliary contact SW is switched from the closed state to the open state in the initial stage of the retracting operation of the movable core 320 as shown in FIG.

  Then, the energization pattern changes from the first energization pattern to the second energization pattern in the middle of the operation of drawing the movable iron core 40 toward the fixed iron core 30 (the stage before the moving amount of the movable iron core 40 reaches the specified value A in FIG. 1). It will be switched. In this case, the magnetic attraction force is reduced in spite of the retraction operation, and the movable iron core 40 cannot be reliably drawn to the fixed iron core 30 side, so that the reliability of the opening and closing of the main contact 51 is lowered. .

  In this respect, according to the present embodiment, the switching of the energization pattern is performed at an appropriate timing after completion of the retracting operation of the movable iron core 40 as described above, and as a result, the magnetic attractive force is reduced during the retracting operation. Therefore, the movable iron core 40 can be reliably retracted until it contacts the fixed iron core 30.

  Therefore, by switching the energization pattern, it is possible to reliably switch the main contact 51 from the open state to the closed state while suppressing the power consumption of the circuit, and the reliability of the opening / closing operation of the main contact 51 is increased.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIGS.
In the first embodiment, the electromagnetic coil 35 that generates magnetic force is the one in which the hold coil 36 and the pickup coil 37 are connected in series. In the second embodiment, the electromagnetic coil 135 is provided with the hold coil 136 and the pickup coil 137. A parallel connection is used.

  And the structure of the electromagnetic coil drive circuit 200 is partially changed with respect to the structure of the electromagnetic coil drive circuit 100 of Embodiment 1 with the change of coil connection. Briefly described with reference to FIG. 5, the electromagnetic coil drive circuit 200 of the second embodiment is provided with a parallel line L4 instead of the bypass line L2 in the electromagnetic coil drive circuit 100 of the first embodiment.

  The parallel line L4 connects the pickup coil 137 in parallel to the hold coil 136, and the P-channel field effect transistor MOSFET3 constituting the switching circuit 110 is seen from the pickup coil 137 on the parallel line L4. And provided near the power supply V. The MOSFET 3 has a drain D connected to the pickup coil 137 and a source S connected to the drain D of the MOSFET 1 provided on the power supply line L.

  The circuit configuration of the switching circuit 110 is the same as the circuit configuration of the first embodiment, and includes a normally open contact auxiliary contact SW as an operation switch.

  With such a circuit configuration, it is possible to perform the same circuit operation as that in the first embodiment, that is, switching of the energization pattern.

  More specifically, when an H-level control signal Sr is input to the gate G of the field effect transistor MOSFET2, both the field effect transistors MOSFET1 and MOSFET2 are turned on and the energization line L1 is closed.

  At this time, in the switching circuit 110, since the auxiliary contact SW functioning as an operation switch is in an open state, the field effect transistor MOSFET4 is turned on (the potential of the gate G is H level). As a result, the field effect transistor MOSFET3 is turned on, and the parallel line L3 is closed.

  From the above, when an H level control signal Sr is input to the gate G of the field effect transistor MOSFET2, an excitation current flows through both the hold coil 136 and the pickup coil 137 as shown in FIG. One conduction pattern).

  The magnitude of the excitation current flowing through the coil is larger in the pickup coil 137 than in the hold coil 136, and the pickup coil 137 is strongly excited. Thereby, a strong magnetic attraction force is generated between the iron cores, and the movable iron core 40 is drawn to the fixed iron core 30 (retraction operation).

  When the movable iron core 40 is pulled in until the movement amount reaches the specified value A, the iron cores 30 and 40 are in contact with each other as shown in FIG. At this time, the main contact 51 that is open in the non-energized state is closed.

  When the main contact 51 is closed, the auxiliary contact SW that operates mechanically in conjunction with the main contact 51 is also in contact with the movable contact and the fixed contact, and is in the closed state as shown in FIG. Become.

  Thus, when the auxiliary contact SW that has been in the open state immediately after the input of the H level signal is in the closed state, each FET constituting the switching circuit 110 is actuated using this as a trigger, and the energization pattern for the electromagnetic coil 35 is the above-mentioned first The energization pattern is switched to the second energization pattern that supplies the excitation current only to the hold coil 36.

  More specifically, with reference to FIG. 6, when the auxiliary contact SW is switched from the open state to the closed state, the field effect transistor MOSFET 4 is turned off (the potential of the gate G is L level). Then, as a result of the field effect transistor MOSFET3 being turned off, the parallel line L4 is opened (open circuit). Therefore, as indicated by the alternate long and short dash line in FIG. 6, the excitation current is supplied only to the hold coil 136 (second energization pattern).

  From the above, the hold coil 136 is excited, a magnetic attraction force is generated between the fixed iron core 30 and the movable iron core 40 to maintain the contact state between both iron cores, and both iron cores 36 and 37 are held in contact. (Hold operation). As a result, the main contact 51 is maintained in the closed state.

  Also in this embodiment, since the auxiliary contact SW of the normally open contact is used for the operation switch that operates the switching circuit, the movable core 40 contacts the fixed core 30 at the timing when the switching circuit 110 operates. Therefore, the switching from the first energization pattern to the second energization pattern is inevitably performed when the movable core 40 is in the retracted state until it comes into contact with the fixed core 30.

  Therefore, the magnetic attractive force does not decrease during the retraction operation, and the movable iron core 40 can be reliably retracted until it contacts the fixed iron core 30, so that the main contact 51 can be reliably switched from the open state to the closed state. Thus, the reliability of the opening / closing operation of the main contact 51 is increased.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  (1) In Embodiments 1 and 2, unipolar transistors (that is, field effect transistors FET) are used as the “semiconductor switching elements” of the present invention. However, bipolar transistors may be used. .

  (2) In the first embodiment and the second embodiment, the example in which the main contact that is in the open state in the non-energized state is switched to the closed state by the energization operation to the electromagnetic coil has been described. Of course, the main contact that is in the closed state in the non-energized state can be switched to the open state.

Sectional drawing which shows the mechanical structure of an electromagnetic contactor in Embodiment 1. The figure which shows the circuit structure of an electromagnetic coil drive circuit Explanatory drawing explaining the circuit operation of the electromagnetic coil drive circuit (first energization pattern) Explanatory drawing which similarly explains the circuit operation of an electromagnetic coil drive circuit (second energization pattern) In Embodiment 2, the figure which shows the circuit structure of an electromagnetic coil drive circuit (1st electricity supply pattern) Diagram showing circuit configuration of electromagnetic coil drive circuit (second energization pattern) Illustration explaining the problem Figure explaining problem similarly Figure explaining problem similarly

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Electromagnetic contactor 30 ... Fixed iron core 35 ... Electromagnetic coil 36 ... Hold coil 37 ... Pick-up coil 40 ... Movable iron core 51 ... Main contact 53 ... Fixed contact 55 ... Movable contact 100 ... Electromagnetic coil drive circuit 110 ... Switching circuit SW ... Auxiliary Contact (normally open)
L1 ... Power supply line L2 ... Bypass line L3 ... Connection line L4 ... Parallel line MOSFET3 ... P-channel field effect transistor MOSFET4 ... N-channel field effect transistor R7 ... Current limiting resistor

Claims (3)

An electromagnetic coil drive circuit of an electromagnetic contactor comprising a main contact that opens and closes by energization operation on an exciting electromagnetic coil, and an auxiliary contact that opens and closes mechanically linked to the main contact,
A pickup coil with one end connected to the ground;
A hold coil connected in series to the pickup coil and constituting the electromagnetic coil together with the pickup coil;
A power supply line drawn from a power supply and supplying an excitation current to the electromagnetic coil;
A bypass line that connects both ends of the hold coil to each other, and bypasses the hold coil with an excitation current supplied through the power supply line, and flows only to the pickup coil;
A switching circuit for switching an excitation current supplied through the power supply line to a first energization pattern for supplying only to the pickup coil and a second energization pattern for supplying to both the pickup coil and the hold coil. As
Of the auxiliary contacts, normally closed auxiliary contacts that are in contact with each other when the magnet coil is not energized and closed when energized are normally closed contacts, while the contacts are separated when de-energized. When a normally open auxiliary contact that is open is defined as a normally open contact,
The switching circuit includes at least a semiconductor switching element provided in the bypass line and an operation switch including a normally open contact type auxiliary contact, and the auxiliary contact that is the operation switch is switched from an open state to a closed state. When the circuit is operated under conditions and the semiconductor switching element in the on state that closes the bypass line is switched to the off state that opens the bypass line, the energization pattern from the first energization pattern to the second energization pattern An electromagnetic coil drive circuit for an electromagnetic contactor, characterized in that the circuit configuration is such that the switch is switched. An electromagnetic coil drive circuit of an electromagnetic contactor comprising a main contact that opens and closes by energization operation on an exciting electromagnetic coil, and an auxiliary contact that opens and closes mechanically linked to the main contact,
A hold coil having one end connected to the ground and the other end connected to the power line;
A pickup coil connected in parallel to the hold coil and constituting the electromagnetic coil together with the hold coil;
A switching circuit for switching an excitation current supplied through the power line to a first energization pattern that supplies both the pickup coil and the hold coil and a second energization pattern that supplies only to the hold coil. And
Of the auxiliary contacts, normally closed auxiliary contacts that are in contact with each other when the magnet coil is not energized and closed when energized are normally closed contacts, while the contacts are separated when de-energized. When a normally open auxiliary contact that is open is defined as a normally open contact,
The switching circuit includes at least a semiconductor switching element provided in a parallel line connecting the pickup coil in parallel to the hold coil, and an operation switch including a normally open contact type auxiliary contact, and the operation switch The circuit is activated on the condition that the auxiliary contact is switched from an open state to a closed state, and the semiconductor switching element in an on state that closes the parallel line is switched to an off state that opens the parallel line. Thus, the electromagnetic coil drive circuit of the electromagnetic contactor has a circuit configuration in which the energization pattern is switched from the first energization pattern to the second energization pattern. The switching circuit is
A P-channel field effect transistor as the semiconductor switching element having a source connected to the power supply side on the bypass line or the parallel line and a drain connected to the pickup coil side;
An N-channel field effect transistor having a source connected to the ground side and a drain connected to the gate of the P-channel field effect transistor;
The gate of the N-channel field effect transistor is connected to the power supply side through a current limiting resistor, the potential of the gate is set to H level, and the N-channel field effect transistor of both ends of the current limiting resistor is connected. The electromagnetic coil drive of an electromagnetic contactor according to claim 1 or 2, wherein the end portion on the side connected to the gate is connected to the ground by the normally open contact type auxiliary contact. circuit.

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