FR2592212A3 - Three-pole motor protection circuit breaker - Google Patents

Abstract

The circuit breaker is built up from half shells (37,38,39,40) which together form the three separate chambers for the contacts. Typically, there are two end shells (37,38) and two identical double half shells (39,40). On top of the block formed by this assembly (37-40) is the mechanical linkage system (53) which joins all the poles together mechanically, and also the automatic release device (51) for all poles. Each pole of the circuit breaker has an instantaneous magnetically operated overcurrent trip, and also a thermal overload release. These tripping devices are coupled to the automatic release device (51) thus ensuring that all poles are opened when an overcurrent is detected on one pole. Manual close-open facility (52) is also provided.

Description

 The invention relates to a polyphase, in particular three-phase protection switch for a motor, the protection functions of which consist in tripping, that is to say, simultaneously cutting all the phases of the network in the event of an overcurrent of a certain duration. or short-circuit current, on at least one of the phases, having the following elements - an active part, traversed by the currents of the different phases when the switch is in the "on" position, fitted with pieces of contact for each phase, -a trigger kinematics, common to all the phases, -and a switch mechanism controllable both manually and by the trigger circuitry, which is able to cause a simultaneous breaking of all the contacts.

 Motor protection switches, in various embodiments, have been contacted for decades, which, as their name suggests, are used to protect large and medium-sized electric motors, preferably those supplied with alternating current. .

The protection functions of the motor protection switches must operate first in the event of a current overcurrent of a certain duration, and also in the event of a short-circuit current and cut off the mains motor, even if a overload or short circuit only occurred in one of the different phases. Many of the motor protection switches also fulfill their cut-off function in the event of a phase failure or in the event of undervoltage.

Protection switches for mms srk motors, as a rule, consisting of a solid body common to all phases, in which, apart from the contact parts themselves, are also arranged the other operating elements such as for example bimetal members , a switch mechanism and multiple transmission levers, hereinafter referred to as "trip kinematics". Depending on the trip criteria to be met, there are in the body of the motor protection switch a variable number of pie these and function groups, but in all cases the construction and assembly are quite complicated and, in any case for the layman, confused at first. operation, in which all the expected response criteria for each of the different phases are tested. If on one of the phases only one of the response criteria is not satisfied, or is, but not in the expected response domain, the switch is to be classified as practically discarded. Due to the large number of response criteria satisfied and consequently the ever increasing response precision requirements, the rate of waste is far from negligible, but eliminating the cause of the fault on the device in question is often too costly, especially when partial disassembly of the cited elements is necessary,
Numerous protection switches for known motors with a common body for all the functional parts have drawbacks tending to the fact that after several breaking processes of currents of current close to the nominal current limit, certain disturbing influences can be exercise on the trip kinematics, but also on neighboring switch parts. This is even more evident when a short-circuit current appears; in this case, in fact, the affected contact clamp and its environment are subjected to high thermal stresses and also, at least ir.directly, to mechanical stresses.

 The object of the invention is to avoid, in a new protection switch for an engine, of the kind mentioned at the start, the drawbacks exposed, that is to say to a large extent avoid possible disturbing influences of contacts of the different phases, in addition, to ensure a high response speed of the motor protection switch in the event of a short circuit and finally to design the construction of the device so that it can be assembled from in an easy and at least partially automatic way. In addition, 1 must be added the requirement, especially formulated for series products, of the manufacture of the apparatus under advantageous cost price conditions without loss of quality. that is to say in particular without loss of safety and endurance of the device.

 A solution to this complex of problems is obtained according to the invention by the proposal which consists in placing the active part in a body formed of several juxtaposed elements, the number of which is equal to the number of phases to be received, plus one), then to provide in this body for each phase a narrow cavity, partially open towards the triggering kinematics and the switch mechanism, for the rest practically closed in all directions, with contact parts accessible from the outside, to have more '' Stdrieur each cavity, in addition to the contact parts and if necessary an anti-parasite device associated, a magnetic circuit breaker reacting to the appearance of a short-circuit current by a blade which moves in case of tripping, as well that a temperature-sensitive blade-shaped member which moves in an increasing manner as a function of the intensity of the current, and finally to pass the free ends of the blades out of the cavities can deviate from the magnetic circuit breakers as well as the organs in the form of displaceable blades sensitive to temperature and make them protrude in a separate body which covers all the cavities of the main body of the active part and which also receives the kinematics of trigger.

 The decomposition of the body of the active part into several elements and the formation of practically closed cavities for each phase makes it possible to collect the spare parts necessary for each phase during a pre-assembly into a body element and submit this item to a verification process. If, on this occasion, a function is not fulfilled, it suffices to discard this element, but not the other elements which, assembled, contribute to the creation of an active part. In addition, the number of parts to be placed in each element is significantly lower than in a complete active part to be assembled, so that it is easier to reuse the scrap element, thanks to a very simple operation, it is that is to say the exchange of a part (which in this case is much simpler than in the case of an active part completely mounted. The fact of providing an anti-parasite device (in any case for a active part of high nominal power) and the equipment of each phase of a magnetic circuit breaker (known in itself) reacting in the event of a short-circuit current, gives the active part a high response speed in the event of a short-circuit and, in addition, a high breaking capacity, Thanks to this configuration of the active part of a motor protection switch, there is another advantage which cannot be overlooked at first glance, but which nevertheless deserves a lot of attention, namely the use of identiq parts and elements ues od at least approximately identical, as we need for line protection circuit breakers. On this subject it can be noted that. In a manufacturing plant there are many more line protection circuit breakers than protection switches for lines. motors, and thus these parts and elements can be manufactured in a particularly economical manner, also because the number of parts for a phase can be greater than in the case of current protection switches for motors and that finally these are, in the case of parts of line protection circuit breakers to be used, parts and elements which have been particularly tested and developed.

The construction of the parts in each cavity, for each phase, can correspond exactly to that of the line protection circuit breakers, with the exception of the switching mechanisms of the line protection circuit breakers.

 As a result of a concrete configuration proposal, the body of the active part can consist of two end pieces in the form of half-shells (so called) and, depending on the number of phases desired, one or more intermediate parts having the shape of two opposite half-shells with a common base. Then the body elements are formed which, as regards the capacity and the internal configuration of the different cavities to be formed, imitate the interior of the bodies of line protection circuit breakers, without however requiring for each phase two distinct half-shells. This would be a solution for forming the cavities, but the number of parts would be unnecessarily high.

 Another advantageous configuration proposal consists in assembling the body elements for the body of the active part, after equipping them, assembling them and if necessary a function check, in a manner which is difficult to dismantle or cannot be dismantled. In particular, according to a new configuration proposal, the assembly of the body elements can be done by snap-fastening which is difficult to dismantle or cannot be dismantled without destruction or even by riveting, in particular by means of tubular rivets or the like. In this way it is possible to prevent manipulations on the device, after final assembly of the protective switch, or of its active part. In particular, it is practically possible to prevent non-specialist users of the device from trying to repair the device. in case of failure.

 A development proposal of a kind similar to the conformation proposal which has just been mentioned consists in carrying out the assembly of the complete body of active part and of the separate body intended for the triggering kinematics, also with latching means. formed from these bodies and difficult to disassemble or removable without destruction, centering means in the form of pins or rods and corresponding cavities ensuring exact positioning of the elements between them. Here too, what has just been said concerning unwanted manipulation is valid; in addition, a.-tfile and-oTe * irt mount.

precise as regards positioning can be done by means of such latching means and additional centering means, this mounting furthermore being suitable for advanced automation.

 An adequate development of the concept of the invention lies in the proposal which consists in equipping the body of the active part, on its face opposite to that which receives the triggering kinematics, with conformations. and snap-on means which allow it to be fixed to a standardized profile (for example on a dhçe profile). Such a possibility of fixing the motor protection switch can be combined with the other possibility of fixing provided by screws, so that a variety of fixing possibilities can be offered.

 The latest development proposal can even more advantageously be shaped in such a way that the external dimension in width of the body of the active part, that is to say in the longitudinal direction of the profile which receives, where appropriate, the motor protection switch, is a multiple of the current width standard of 17.5 mm in "narrow series" for single-phase switches or circuit breakers. Such agreement with the width standard comes to the fore design and installation technicians.

The inventive idea and its possibilities of advantageous configurations will be further explained and clarified on the basis of the non-limiting examples of execution and the explanations which follow, with regard to the assignments on which
Figure 1 shows a view of the active part of a motor protection switch open from the side of the observer;
Figure 2 shows a perspective view of the active part, here closed, already shown in Figure 1, of a motor protection switch
Figure 3 shows a perspective view of body elements placed one behind the other at a distance, intended for the active part shown in Figures 1 and 2
Figure 4 shows a perspective view of the active part already shown in Figure 2, with however the trigger kinematics mounted on the top and a switch mechanism common to all phases; and
Figure 5 shows a perspective view of a motor protection switch with a separate active part, whose body is shaped differently than the bodies shown above.

 FIG. 1 represents a sectional view in the direction of the observer of an active part 10 of a polyphase protection switch for a motor. One recognized an element of body 11. which, as will be explained later in detail, forms a. denibociille open in the dDintion of the osserator, and which is represented, for reasons of observation, partially in section parallel to the plane of representation and, consequently, is hatched at the place of the sections. On the left and right in the representation, one can recognize the contact terminals 12 and 13, which are widely covered by the edges 14 and 15 of the body element. but to which one has access from the outside through the working openings 16 and 17 and the openings 18 and 19 for introducing the lines. Between the contact terminals 12 and 13 is formed a cavity 20 open upwards (in the representation), but for the rest practically closed in all directions, in which the functional elements are arranged for a phase, which remains to be explained. In detail, this is a magnetic circuit breaker 21, with a blade 22 which moves in the event of a circuit breaker, pWs of a member 23 in the form of the, sensitive to the tadrature cpi is placed in an increasing fashion. as a function of the intensity of the current and finally of a fixed contact 24, as well as of a pack of blades 25 intended to smother the sparks, whose individual sheets for extinguishing sparks are not visible in this representation. Upwards, the cavity 20, as not just mentioned, is essentially open but already practically closed on this representation by the lower part 26 of a body, not shown for the rest, intended for the kinematics of by a remaining opening 27, a movable contact connected to a mechanical switch, also not shown, can enter the cavity 20, and cooperate with the fixed contact 24; through the openings 28 and 29 of the lower part 26 already mentioned, protrude the free ends of the blade 22 already mentioned and of the member 23 sensitive to temperature. From the lower part 26 there also leave hooks 30, 31 and 32 which engage with the upper part (not shown) of the body already mentioned which receives the trigger kinematics, which need not be explained. here in more detail. However, mention should be made of the shape of the part, facing downwards in the representation, of the body element 11 which has a recess 33 in the general shape of a dovetail extending perpendicularly in terms of the drawing, the contours of which are however easier to recognize in the following Figures 2 to 4.

On the left side (in the representation) of this recess 33 in the form of a dovetail, there is a lock 34 with spring which can grasp from behind a wing of a support profile in the form of a ducket profile not shown here , which we talked about at the start.

 The different parts and also the general shape of the body element 11 correspond essentially to those of a known line protection circuit breaker, but however only up to the edge turned upwards in the representation of the body element 11. Parts located above in a line protection circuit breaker, such as a manual switch control and a switch mechanism are in principle also present in this switch, see Figure 4 and the explanations which attach to it, but these parts and their attachment do not eorrespgnx tooth more exactly -audit line protection switch. The use of parts identical to those of the line protection circuit breaker known to equip the element 11 with a body is completely intentional and provides the advantage of being able to use parts and assemblies already proven for the motor protection switch, and moreover, of being able to increase the number requirements of these parts and assemblies in manufacturing, which gives an advantage of price. It is assumed in this case that the line protection circuit breakers and the motor protection switches described and shown here are produced by the same manufacturer, which is generally the case.

 FIG. 1 therefore represents a body element 11 with the equipment for a phase. However, the protection switch for the motor to be created must simultaneously protect several phases, in particular three, and therefore needs an active part with several phases, that is to say three phases.

Figure 2 shows such an apparatus. It recognizes, in perspective, an active part 36 for three-phase motor protection switch.

This active part 36 is in the form of a body which consists of two end pieces 37 and 38 and two intermediate pieces 39 and 40. The end pieces 37 and 38 are in the form of half-shells ( so named) which, when assembled, are turned towards each other. The intermediate parts form two opposite half-shells with a common base.

In this way, a total of three cavities 41, 42 and 43 is formed, that is to say one for each phase to be protected, or to be cut. The parts contained in these various cavities 41 to 43 correspond to those biting in FIG. Once again above these cavities 41 to 43 there was a lower part 44 of a body intended for the triggering kinematics not shown here.

Through openings (not referenced) made in this lower part 40 protrude the free ends of the movable blades of magnetic circuit breakers (the blade closest to the observer is referenced 45) as well as the blades of organs sensitive to temperature ( the temperature sensitive member closest to the observer is referenced 46). This also corresponds to the construction and to the parts of figure 1. After their assembly and if necessary verification of the different phases and / or response criteria, the elements 37 to 40 are assembled with their content, as can be seen in the Figure 2. The assembly openings 47, 48 and 49 common to all the elements 37 to 40 are used to receive assembly elements, such as tubular rivets, or the like (not shown here in detail). Once the assembly has been carried out (for example with tubular rivets), the elements 37 to 40 can no longer be separated from one another without destroying or damaging these assembly means. In this way, it is impossible for the user of the engine protection to access the interior of the active part to carry out operations there, say "repairs". This was done quite consciously to induce the user to change ~ the complete device in case of failure of a motor protection switch, and this in his own interest. Experience has shown that the "repair" of a motor protection switch at the place of use is not possible, since there are no precise verification possibilities there.

 FIG. 3 once again represents the body elements already shown and referenced on. Figure 2, namely the end pieces 37 and 38, the intermediate pieces 39 and 40 and this in perspective, arranged one behind the other with a certain distance. We recognize the half-shell shape of the two end pieces 37 and 38, with an approximate U-shaped section and the intermediate pieces 39 and 40, with an approximate H-shaped section, this section being imaginary just below the top edge of the elements. JCuLtefiçjreoemcntre not detail forms inside 11 half-shells, for example those intended to serve as support for the various parts which are housed therein.

 FIG. 4 once again represents the active part 36 shown in FIG. 2 with its body elements 37, 38, 39 and 40, which are already assembled here with kinematics 51 for triggering and a control 52, the latter cooperating with a mechanism 53 switch. This switch mechanism 53 is furthermore equipped with a contact support 54 which receives the mobile contacts (only the mobile contact closest to the observer is recognized here) for all the phases.

 The trigger kinematics 51 as well as the switch mechanism 53 and the contact support 54 are additionally, in this protection switch for motor, covered with a cover which is not shown here.

 FIG. 5 shows a protection switch for an engine, with an active part 57, the body of which also consists of elements 58 to 61.

The elements 58 to 61 deviate, as regards the configuration of their contact terminals, from those shown in. the figures described above, but inside as regards precisely the parts, they largely correspond to the construction presented in FIG. 1. This active part 57 also adjoins, above in the representation, with a kinematics 62 for triggering which is itself connected to a switch mechanism 63 (shown only schematically) in an appropriate manner.

The trigger kinematics 62 and the switch mechanism 63 are here covered only by a cover 65 which protects the switch mechanism 63 and also the interior of the active part 57 from dirt and unwanted interventions.

 As already expressed at the beginning of the description of the figures, the figures which have just been described represent only examples of execution of the active part of a motor protection switch, and in particular of the constitution of the body of this active part. Many variants of the examples of execution shown are conceivable and achievable without departing from the scope of the invention.

Claims (7)

 1) Polyphase protection switch, in particular three-phase for motor, whose protection functions consist in tripping, that is to say, simultaneously cutting all the network phases in the event of an overcurrent of a certain duration or short-circuit current occurring at least on one of the phases, which essentially consists of an active part, traversed by the currents of the different phases when the switch is in the "on1" position, fitted inside the parts of contact for each phase, further consisting of a trigger kinematics common to all phases, and finally of a switch mechanism controllable both manually and by the trigger kinematics, which is able to cause a simultaneous breaking of all contacts, characterized in that the active part (10, 36, 57) consists of a body made up of several elements (11; 37 to 40) assembled with each other, including the number e of elements exceeds the number of phases to be accommodated by one unit, i.e. the number of phases plus one, that in the frame is formed for each phase a narrow cavity (20, 41 to 43 ) separate, partially open towards the release kinematics (26, 44, 51, 62) and towards the switch mechanism (53, 63), and for the rest practically closed in all directions, provided with contact parts (12, 13 ) accessible from the outside, that inside each of the cavities outside the contacts (24, 55) and, where appropriate, an associated anti-parasite device (25), are arranged a magnetic circuit breaker (21) reacting to the appearance of a short circuit, with a blade (22) which moves in the event of disjunction, as well as a temperature-sensitive member (23) in the form of a blade, which moves in increasing fashion depending on the current inimsitX, and that the free ends of the blades displaceable by the magnetic circuit breakers as well as the organs sensitive to temperature stripped out of the cavities and protrude into a separate body (26, 44) which covers all the cavities of the break of the active part and also receives the kinematics of dcleoehet (51, 62).  2) Motor protection switch according to claim 19, characterized in that the body of the active part (36) consists of two end parts (37, 38) in the form of dr "coru1.lies and, depending on the number of phases, one or more J-CC2S (39, 40) intermediaries which have the shape of two opposite half-shells with a common base.  3) Motor protection switch according to claim I or 2, characterized by the fact that the body elements (37 fi 40) are, after their equipment, their assembly and if necessary a function check, combined so as not to not be removable or difficult to be.  4) motor protection switch according to claim 3, characterized in that the assembly of the body parts (37 to 40) is by snap difficult to disassemble or impossible to disassemble without destruction, or by riveting, in particular with tubular rivets or the like.  5) Motor protection switch according to any one of claims 1 to 4, characterized in that the assembly between the body (37 to 40) complete with the active part (36) and the separate body (44) intended triggering kinematics is also done by means of latching preferably formed from parts of the main body or separate body, difficult to disassemble or disassemble without destruction, centering means in the form of projections or rods and corresponding cavities ensuring exact positioning of the main body and the separate body with respect to each other.  6) Motor protection switch according to any one of claims 1 to 5, characterized in that the body (11) of the active part (10) is equipped on its face opposite to the kinematics (26) for triggering receive, conformations and latching means (34), which allow its attachment to a standardized profile.  7) Motor protection switch according to claim 6, ca acterized in that the outer dimension in width. of the body (37 to 40) of the active part (36), that is to say the external dimension of the body measured in the direction of the length of the standard profile which receives the motor protection switch if necessary, is a multiple of the standard width of 17.5 mm valid in "narrow series" for switches or single-phase protective switches.