EP2016604A1

EP2016604A1 - Electromagnetic contactor

Info

Publication number: EP2016604A1
Application number: EP07731303A
Authority: EP
Inventors: Bruno Lefebvre
Original assignee: ABB France SAS
Current assignee: ABB Schweiz AG
Priority date: 2006-05-09
Filing date: 2007-04-16
Publication date: 2009-01-21
Anticipated expiration: 2027-04-16
Also published as: FR2901056A1; US20090219119A1; US7902947B2; CN101356613B; WO2007128892A1; EP2016604B1; ES2645241T3; FR2901056B1; CN101356613A

Abstract

electromagnetic contactor comprising a winding (6) for generating a magnetic field, a magnetic circuit comprising a stationary portion (7) and a mobile portion (8), and an electronic board (11) comprising means of controlling the power supply to the winding (6), the electronic board (11) being arranged horizontally above the stationary portion (7) of the magnetic circuit. The mobile portion (8) passes through the electronic board (11) via an opening (12) in the board and slides into the winding, the contactor comprising an insulating casing including a rear portion intended to be fastened onto a support.

Description

Electromagnetic contactor

The present invention relates to an electromagnetic contactor. In particular, the invention relates to an electromagnetic contactor intended to be fixed on a support rail, in contact with other electrical devices.

In known manner an electromagnetic contactor comprises:

a coil for generating a magnetic field,

a magnetic circuit comprising a fixed part and a mobile part.

Elastic means are provided to keep the fixed and movable parts apart in the absence of supply of the coil.

In general, the electrical operation of a contactor can be described in two distinct phases.

During a first call phase, when the coil is supplied with current, the magnetic circuit tends to close, the moving part coming closer to the fixed part until these two parts are in contact. During this phase, a large power is needed to overcome the starting gap, and move the moving part against the action of the elastic means. This so-called power call power is related to the number of ampere-turns of the coil, that is to say the product of the number of turns of the coil and the value of the current intensity in the coil.

During a second holding phase, the magnetic circuit must remain in the closed position as long as the supply of the coil is present. In this second phase, the amperes-turns necessary level is much lower than in the call phase, because the gap is zero, and the magnetic forces are maximum.

In general, the contactors can be supplied with direct current or alternating current.

Specific electromagnet technologies to reduce the power required and therefore the consumption of the contactor during the phases of call and / or maintenance have existed for many years. It is known in particular to use, for a continuously-controlled contactor, alternating-control laminated sheet circuit boards with a two-winding coil or solid circuits with or without permanent magnets. The use of these technologies leads usually an increase in the size of these contactors compared to the alternative control version.

It is also known, in particular from EP 0 789 378, to equip an alternating laminated circuit contactor with an electronic card for controlling the supply of the coil.

This card makes it possible in particular to supply the coil with direct current, whatever the supply voltage, alternative or continuous. The card also increases the supply voltage range that can be used by the contactor. The card also makes it possible to reduce shocks during the call phase and consumption during maintenance. Because of the extra cost of the electronic card, this solution is reserved for medium and large devices, greater than 50 A.

It is also known to use a laminated-type magnetic circuit with an electronic card arranged laterally in the contactor housing with respect to the coil, and perpendicular to the mounting plane, in particular to limit on-demand consumption and to make them compatible with PLC outputs.

However, it appears that this solution imposes a specific and limiting positioning of the power supply terminals of the card which again leads to an increase in the size of the devices when this solution is available on different sizes of contactors.

For all contactors, it is desirable to meet the following criteria:

- a reduced call consumption, if possible compatible with the PLC outputs,

- consumption during the reduced maintenance phase,

- the acceptance of wide ranges of DC or AC supply voltage,

a footprint identical to that of an alternative device of equivalent caliber, and

- A realization cost identical to that of a conventional alternative device.

However, it is difficult to reconcile all of these criteria. EP 0 751 545 discloses an electromagnetic contactor comprising:

a coil for generating a magnetic field, a magnetic circuit comprising a fixed part and a moving part, and

an electronic card comprising means for controlling the supply of the coil, the electronic card being arranged horizontally above the fixed part of the magnetic circuit.

This contactor is however intended for automotive application, in which it is possible to allow a large bulk of the contactor along the axis of movement of the movable part of the armature. As a result, this contactor comprises a movable armature which passes through the fixed armature and extends towards the rear of the contactor with respect to the coil.

Such an arrangement can not be envisaged for a switch intended to be positioned on a support rail by fixing means disposed at the rear of the coil.

Therefore, the present invention aims to provide a contactor to be fixed on a support, whose size is reduced.

The present invention also aims to provide a contactor to meet the above criteria in an improved manner.

For this purpose, the subject of the present invention is an electromagnetic contactor of the aforementioned type, characterized in that the contactor comprises an insulating housing comprising a rear part intended to be fixed on a support and in that the mobile part passes through the electronic card by an opening of the card and slide inside the coil

The arrangements according to the invention make it possible to limit the size of the contactor.

Such a switch also provides the advantages mentioned above for an electronic card.

Preferably, the contactor comprises connection terminals of the coil being located in the plane of the electronic card.

This arrangement of the connection terminals makes it possible on the one hand to maintain connections of the power supply to the contactor made in the same manner as a conventional contactor, that is to say above the coil, and secondly to further limit the size of the contactor.

According to one embodiment, the fixed and mobile parts of the magnetic circuit have substantially axisymmetric shapes.

The axisymmetrical structure of the magnetic parts offers a better performance than a conventional flat structure. Advantageously, the fixed and mobile parts have opposite conical portions, one convex and the other concave.

The electronic card makes it possible to limit the shocks during the call phase and therefore to considerably reduce the contact surfaces of the two armatures without exposing the magnetic circuit to premature wear, and without increasing the time of conjunction.

It is therefore possible to use the conical shape, "progressive air gap", which decreases the ampere-turns necessary to the call because the effective air gap is smaller than the actual stroke of the mobile core.

The combination of the above characteristics consequently makes it possible to obtain a contactor with reduced call power, and reduced overall volume, equivalent to a contactor of the same range but having no reduced call power.

The duration of the call phase with the contactor according to the invention is of the same order as that of a contactor of the same range, having no reduced call power.

According to one embodiment, the fixed and mobile parts are made in massive elements.

The massive structure of the magnetic parts allows an optimization of the forms and the choice of the materials and to use processes of production of large series, like the stamping, the cold stamping, or the cutting. These provisions thus make it possible to reduce the costs and the complexity of the manufacture.

Advantageously, the fixed part forms a housing in which the coil is received.

According to one embodiment, the fixed part of the magnetic circuit comprises at least one lateral opening.

The presence of an opening allows the passage to the outside of the body of connection means of the coil, in particular son or portions of conductors. The realization of this opening thus makes it possible to limit the vertical dimension of the contactor since the passage of the means for connecting the coil is made at the side wall of the body of the fixed armature, and not above it.

According to one embodiment, the fixed part of the magnetic circuit comprises:

a cylindrical portion, a bottom at a first end of the cylindrical portion, and

a wall comprising a passage opening of the movable part at a second end of the cylindrical portion.

Advantageously, the lateral opening is constituted by a notch in the edge of the cylindrical portion forming the second end of the cylindrical portion.

Advantageously, the fixed part of the magnetic circuit comprises:

a body forming the cylindrical portion and the bottom, and

- A cover forming the wall comprising a passage opening.

This arrangement makes it possible to produce the fixed part of the magnetic circuit from two simple shapes that are easier to produce. In addition, this arrangement facilitates the assembly of the coil in the fixed part of the frame. It allows to facilitate the production of the part, and to realize this production in large series.

Advantageously, the elements of the contactor are stackable.

This arrangement facilitates the assembly of the contactor. In particular, the stacking can be performed by a simplified automated process.

According to one embodiment, the power supply control means of the coil are arranged to supply the DC coil, whether the supply voltage of the contactor is alternating or continuous.

Advantageously, the means for controlling the supply of the coil comprise means for determining a current value making it possible to close the contactor or to keep the contactor closed, and means making it possible to limit the average value of the supply current. from the coil to the determined value.

In any case, the invention will be better understood with the aid of the description which follows, with reference to the appended schematic drawing, representing by way of nonlimiting example, an embodiment of a contactor according to the invention.

Figure 1 is an exploded perspective view of a contactor according to the invention.

Figure 2 is an exploded perspective view of the contactor of Figure 1, the parts constituting the housing having been removed. Figure 3 is a perspective view in partial section of the magnetic circuit.

FIG. 4 is a diagram of the electrical circuit of the electronic board of the contactor of FIG.

FIG. 5 is a flowchart of operation of the control means constituted by the electronic card.

Figure 6 is a partial perspective view of a second contactor according to the invention.

FIG. 7 is another partial perspective view at a second angle of view of the contactor of FIG.

FIG. 8 is a detail view, in perspective of the fixed part of the magnetic circuit of the contactor of FIG. 6.

According to an embodiment shown in Figures 1 to 4, an electromagnetic contactor according to the invention comprises an insulating housing comprising a rear portion 2, intended to be fixed on a support, and a front portion 3, intended to be fixed on the rear part 2. On the front part 3 of the housing are fixed fixed contacts not shown. The insulating housing also comprises a terminal block 4 intended to be fixed above the front part, and having connection terminals 5 intended to be connected to the fixed contacts.

The housing parts form a housing in which are received:

a coil 6 for generating a magnetic field, fixed to the housing, and

- A magnetic circuit having a fixed portion 7 relative to the housing and a movable portion 8 relative to the housing.

A movable contact carrier 9 is integrally mounted with the movable portion 8 of the magnetic circuit.

The contact carrier 9 comprises movable contacts intended to be in contact with the fixed contacts, or separated from these fixed contacts, according to the position of the movable part 8, to close or open an electrical power circuit.

Elastic means consisting of two springs 10 are provided to keep the fixed parts 7 and mobile 8 apart in the absence of supply of the coil 6. The contactor comprises means for controlling the supply of the coil 6 in AC or DC voltage, constituted by an electronic card 11.

This electronic card 11, of the type described in EP 0 789 378, is arranged in interface between the external power supply and the power supply of the contactor coil. This electronic card 11 is arranged horizontally above the fixed part 7 of the magnetic circuit, the mobile part 8 passing through the electronic card through an opening of the card 12 and sliding inside the coil and the fixed part 7.

It should be noted that the connection terminals of the coil of the terminal block 5 are located in the plane of the electronic card.

As represented in FIGS. 1 to 4, according to a characteristic of the invention, the fixed and mobile parts 8 and 8 of the magnetic circuit have an axisymmetric shape with respect to an axis A, which coincides with the axis of the coil 6.

In particular, the fixed part 7 of the magnetic circuit comprises:

a body 13 forming: a cylindrical portion 14, a bottom 15 at a first end of the cylindrical portion 14, and

a cover 16 forming a wall comprising a passage opening 17 of the mobile part 8 intended to be positioned at a second end of the cylindrical portion 14.

The body and the cover define a housing in which the coil 6 is received. The passage opening 17, arranged around the axis A. makes it possible to ensure the penetration of the mobile part in the coil 6.

The movable portion 8 comprises a cylindrical portion intended to enter the passage opening 17.

As shown in Figure 3, the fixed parts 7 and mobile 8 have conical portions facing. In particular, the fixed portion comprises a convex conical portion 18 disposed on the bottom 15 of the body 13. The movable portion 8 has a concave conical portion 19. Of course the concave portion could be positioned on the fixed portion and the convex portion on the moving part.

The two conical portions 18, 19 are of a shape adapted to provide an air gap between them when the two fixed and moving parts are in touch with. In particular, the flat end ends 20, 22 of the two conical parts do not come into contact, when the fixed and moving parts are in contact.

Only the edge 23 defining the conical concave portion 19 of the movable portion 8 abuts against the bottom 15 of the body 13.

The fixed parts 7 and mobile 8 are made in solid elements.

The body 13 of the fixed part 7 of the magnetic circuit comprises at its upper edge, on which the cover 16 is positioned, indentations 24. These notches allow the outward passage of the body of connection means of the coil, in particular wires or other portions of conductors.

In addition, these notches allow to improve the cooling of the coil.

According to a second embodiment shown in FIGS. 5 to 8, the contactor comprises substantially the same elements as in the first embodiment. However, unlike the first embodiment, a single return spring 10 is present to separate the armatures in the rest position, this spring being positioned around the movable armature. In this second embodiment, the electronic card 11 comprises an opening constituted by a cutout 12 opening on the edge of the electronic card 11 through which the movable portion 8 of the magnetic circuit passes through the plane of the electronic card. As before, the connection terminals of the coil of the terminal block 5 are located in the plane of the electronic care. The terminal block 5 is a removable terminal block comprising metal tabs 26 intended to be received in elastic lyres 27 mounted on the card 11 to provide the electrical connection.

FIG. 8 shows the embodiment of the indentations 24 at the upper edge of the fixed part of the armature, allowing the passage of the coil connection means comprising flexible wires or rigid conductor portions 25.

As shown in FIG. 4, the electronic card used by the two previously described contactors comprises a filtering component F and a rectifier component Rd making it possible to transform an alternating voltage into a DC voltage. In particular, the rectifier component Rd may comprise a diode bridge. These components make it possible to supply the coil with direct current, whether the supply voltage of the contactor is alternating or continuous.

The electronic card comprises means for determining a current value for closing the contactor or maintaining the contactor closed, and means for limiting the average value of the supply current of the coil to the determined value.

In particular, the coil 6 of the contactor is powered by a step-down chopper device consisting of a power transistor TR, bipolar transistor, MOSFET or IGBT, operating in "all or nothing", controlled by a signal amplitude modulation amplitude "PWM" (pulses width modulation) generated by a control device constituted here by a microcontroller μC; this control device could also be constituted by any other specific logic circuit. The frequency of this signal is fixed and the duty cycle, that is to say the ratio between the conduction time and the signal period, is adjusted by the microcontroller μC.

The coil 6 is connected in series with the power transistor TR, and a resistor R1 used for the measurement of the current.

The microcontroller μC is powered by a power supply component UR delivering a controlled voltage.

The microcontroller μC takes as input:

a signal for measuring the voltage across the resistor R1, which is a measurement of the current in the coil, and

a signal proportional to the supply voltage of the contactor, provided by a voltage divider formed by two resistors R2 and R3.

Depending on the operation of a step-down chopper, the average voltage across the coil of the contactor is the product of the duty cycle by the source voltage.

The adaptation of the duty ratio of the step-down chopper device as a function of the input voltage level makes it possible to feed the coil with a determined constant average value voltage regardless of the power supply value of the contactor. This value can be set to the minimum call threshold during the call phase and the minimum hold threshold during the hold phase.

According to one embodiment, during the call phase, the maximum duty cycle of 100% is reached for the minimum value of the voltage power supply within the operating range of the contactor. In the holding phase, the duty cycle is adjusted automatically according to the current to be controlled.

The coil is further connected antiparallel to a freewheeling diode D.

The freewheeling diode keeps the magnetic energy stored in the coil and limits the overvoltages caused by the switching off of the contactor control. It is thus possible to keep the closing of the contactor in case of micro-cuts or voltage dips, and to perform a clipping of the voltage. These provisions make it possible to mitigate the failures of the supply network.

Figure 5 illustrates the operation of the card, when a supply voltage is established across the contactor.

If no voltage is established, the card is not powered, which is represented in steps E0 and E0 '.

If a supply voltage is established, it is subjected to filtering by the filtering component 12, then a rectification is performed by the rectifier component 13, in a first step E1.

In a second step E2, the nature and the level of the supply voltage are detected.

In a third step E3, the minimum call threshold is calculated. The minimum call threshold is the minimum level of voltage across the coil 6 sufficient to trigger the detachment and closure of the magnetic circuit. With this voltage level, the travel of the moving contacts has sufficient momentum to close the power circuit in good conditions, defined by normative constraints.

In a fourth step E4, a PWM signal is generated to control the supply of the coil to the minimum call threshold.

In a fifth step E5, a test is performed to identify whether a change of slope and the maximum intensity in the coil are reached. If this is not the case, we stay in step E4.

If the test is positive, in a sixth step E6, a regulation of the current at the minimum threshold of maintenance is operated. The minimum holding threshold is the level of current just sufficient to keep the electromagnet closed, taking into account the mounting positions of the contactor, its resistance to shock and vibration, and the number of auxiliary contacts associated, that is to say mechanical loads.

This control is operated until a contactor lock command is received, i.e. until the voltage drops below the minimum contactor supply voltage, which is shown by step E7.

The control logic provides control of the voltage and current during the call phase which reduces the shock and wear of mechanical parts and a current control during the maintenance phase of the contactor, which has the advantage of reducing the power dissipated.

The circuit board 11 allows the contactor to operate over a wide alternating or continuous supply voltage range. The ratio between the minimum and maximum terminals of a supply voltage range is between 1.5 and 3.

It goes without saying that the invention is not limited to the preferred embodiment described above, by way of non-limiting example; on the contrary, it embraces all variants.

Claims

An electromagnetic contactor comprising:

a coil (6) for generating a magnetic field,

a magnetic circuit comprising a fixed part (7) and a movable part (8), and

an electronic card (11) comprising means for controlling the supply of the coil (6), the electronic card (11) being arranged horizontally above the fixed part (7) of the magnetic circuit, characterized in that the contactor comprises an insulating housing comprising a rear part (2) intended to be fixed on a support. and in that the moving part (8) passes through the electronic card (11) through an opening (12) of the card and slides inside the coil, 2. A contactor according to claim 1 comprising connection terminals of the coil (6) are located in the plane of the electronic card.

2. Contactor according to claim 1, wherein the fixed portions (7) and movable (8) of the magnetic circuit have substantially axisymmetric shapes.

3. Contactor according to one of claims 1 to 2, wherein the fixed parts (7) and movable (8) have opposite conical portions (18, 19), one convex and the other concave.

4. Contactor according to one of claims 1 to 3, wherein the fixed parts (7) and movable (8) are formed in solid elements.

5. Contactor according to one of claims 1 to 4, wherein the fixed portion (7) forms a housing in which the coil (6) is received.

6. Contactor according to one of claims 1 to 5, wherein the fixed portion (7) of the magnetic circuit comprises at least one lateral opening (24).

7. Contactor according to one of claims 1 to 6, wherein the fixed portion (7) of the magnetic circuit comprises:

a cylindrical portion (14),

a bottom (15) at a first end of the cylindrical portion (14), and - a wall (16) comprising a passage opening (17) of the movable part (8) at a second end of the cylindrical portion (14).

8. Contactor according to claim 6 and claim 7, wherein the side opening is constituted by a notch (24) in the edge of the cylindrical portion (14) forming the second end of the cylindrical portion (14).

9. Contactor according to one of claims 7 or 8, wherein the fixed portion (7) of the magnetic circuit comprises:

a body (13) forming the cylindrical portion (14) and the bottom (15), and

- a cover (16) forming the wall comprising a passage opening (17).

10. Contactor according to one of claims 1 to 9 characterized in that the contactor elements are stackable.

11. Contactor according to one of claims 1 to 10, wherein the control means of the power supply of the coil (6) are arranged to supply the coil (6) with direct current, that the supply voltage of the contactor either alternative or continuous.

12. Contactor according to one of claims 1 to 11, wherein the power control means of the coil (6) comprise means for determining a current value for closing the contactor (7) or maintain the contactor (7) closed, and means for limiting the average value of the supply current of the coil (8) to the determined value.