Title of Invention

A DEVICE FOR INDICATING AN ELECTRICAL FAULT IN A BREAKING DEVICE SUCH AS A DIFFERENTIAL SWITCH

Abstract

A device for indicating an electrical fault in a breaking device such as a differential switch comprising a pair of separable contacts per pole, in electrical connection with a pair of connection terminals, a contact operating mechanism, comprising a handle connected by a mechanical transmission link to a drive part of the contacts, a trip device comprising a means for detecting an electrical fault and a tripping means such as an electromagnet able to bring about opening of the contacts when automatic tripping occurs following a fault, and -a means for indicating the tripped state of the switchgear apparatus, comprising an indicator able to occupy either a fIrst inactive stable position or a second active stable position indicating the fault due to the action of the electromagnet, characterized in that it comprises a holder, driven by the handle, for holding the indicator in the above-mentioned second position against the action of resetting means for returning said indicator to the fIrst position, so as to store the tripping information until a closing operation of the apparatus is performed.

Full Text

A DEVICE FOR INDICATING AN ELECTRICAL FAULT IN A BREAKING DEVICE SUCH AS A DIFFERENTIAL SWITCH The present invention relates to a device for indicating an electrical fault in a breaking device such as a differential switch comprising: - a pair of separable contacts per pole, in electrical connection with a pair of connection terminals, - a contact operating mechanism, - a trip device comprising a means for detecting an electrical fault and a tripping means such as an electromagnet able to bring about opening of the contacts when automatic tripping occurs following a fault, and - a means for indicating the tripped state of the switchgear apparatus, comprising an indicator able to occupy either a first inactive stable position or a second active stable position indicating the fault due to the action of the electromagnet. Differential switches or circuit breakers are known comprising a means for indicating a differential fault in order to enable the user to detect the presence of an insulation fault in his electrical installation. Some of the known indicating means are in the form of indicator lamps (light-emitting diode systems or other lighted indicators) operating under the dependence of the power supply source of the electrical installation which the circuit breaker protects. This results in optimum safety not being able to be obtained for the user notably on account of the fact that the differential fault information is not reliable whatever the state of the source. Others of these means are mechanical as described in the document EP 0,275,750. In this document, the differential circuit breaker comprises a transformer and a relay cooperating by means of a trip bar with the locking latch of the mechanism and with an indicating lock of a fault indicating lever. The relay used is a relay with two stable positions, of the magnetic latching type. However, this type of relay is relatively expensive and this switch embodiment implements a large number of parts. The document US 4,382,270 is also known which describes another mechanical indicating means of the solenoid type but which has to be reset individually. The present invention proposes a fault indicating device for a breaking device in particular a differential circuit breaker, of simple design, operating independently from the installation power supply source and which is moreover self-resettable, and a switch or circuit breaker equipped with this device. For this purpose, one object of the present invention \s to achieve a device of the kind mentioned previously, characterized in that it comprises a means for holding the indicator in the above-mentioned Second position against the action of a means for returning said indicator to the first position, so as to store the tripping information until a closing operation of the apparatus is performed. According to a particular embodiment of the invention, the indicator is driven positively by the electromagnet between the two above-mentioned positions. According to a particular feature, the above-mentioned tripping means is an electromagnet with a plunger core and the indicator is driven positively by the plunger core between the two above-mentioned positions. According to another feature, the contact operating mechanism comprising a handle connected by a mechanical transmission link to a drive part of the contacts, the means for holding the indicator in the second position is driven by said handle. An object of the present invention is also to achieve a switchgear apparatus and in particular a differential switch or circuit breaker equipped with a device comprising the previous features taken alone or in combination. But other advantages and features will become more clearly apparent from the following detailed description which refers to the accompanying drawings given as examples only and in which : - Figures 1 and 2 are partial longitudinal section views of a differential circuit breaker according to the invention, illustrating a particular embodiment Of the indicating device, respectively in a rest position and in a fault indicating position, - Figures 3 and 4 are partial perspective views of said apparatus corresponding to figures 1 and 2, - Figures 5, 6, 7 and 8 illustrate in perspective respectively the slide rack drive spigot, the indicator, the slide rack and the slide rack return spring, - Figures 9 and 10 are similar views to figures 1 and 2 illustrating another embodiment of the indicating device, - Figure 11 is a partial perspective view illustrating this other embodiment of the device, in an indicating position, - Figure 11a is a similar view to the previous one but showing the device in a rest position, - Figures 12,13,14 and 15 illustrate in perspective, respectively, the slide rack spigot, the indicator, the slide rack and the slide rack spring used in this second embodiment and, - Figure 16 is a general view illustrating the internal part of an apparatus equipped with a device according to the second embodiment of the invention. In the figures, a differential circuit breaker D can be seen housed in a parallelepipedic case 1 made of moulded insulating material designed to be mounted by clipping on a DIN rail (not represented). This circuit breaker D is designed to be connected in an AC power system by means of connection terminals provided in the case 1 and can fulfill several functions. It can in fact trip, and thus interrupt, the electrical circuit when an overload, short-circuit or differential fault occurs. This circuit breaker D comprises a means M for indicating a differential fault enabling the user to diagnose that his electrical installation presents an insulation fault and not an overload fault or a short-circuit fault. By means of this indicating means, the user is immediately operational to locate the insulation fault, which results in the safety of persons and property being able to be efficiently maintained. For simplification purposes, only the differential part will be described in the following. In a manner known in itsetf, this apparatus, in its two embodiments, comprises a pair of separable contacts (not represented) per pole, an operating mechanism for operating the two contacts comprising a handle 2 linked by a mechanical transmission link to a contact driving part, an actuating spring (not represented) for actuation of the mechanism to bring about opening of the contacts when automatic tripping takes place on a fault, a differential trip device having a leakage current detection transformer and an electromagnet 11 designed to cooperate with a locking bolt of said mechanical link of the mechanism. This electromagnet 11 comprises a plunger core 8 designed to slide in a guide tube formed by the shell of a coil when a current flows through the latter, between a rest position figures 1, 3 and 9, 11a and an active tripping position figures 2, 4, 10 and 11. This core 8 is returned automatically to the rest position by a spring 10 after tripping. According to the embodiment of figures 1 to 8, the indicating means M comprises an indicator 5 in the form of a rod articulated around a fixed point 9 of the apparatus, said rod 5 being connected in articulated manner via one of its ends to the core 8 of the electromagnet 11 and comprising at its opposite end a flag 16 designed to operate in conjunction with a window 13 located at the upper part of the case 1. The indicator 5 also comprises a spigot 14 able to operate in conjunction with a staggered part 15 of a slide rack 3 mounted sliding inside the case 1 parallel to the movement of the core 8. This slide rack 3 is driven to slide by the handle 2 between a rest position shown in figure 1 and an active position shown in figure 2 which will be described further on. For this purpose, the handle 2 comprises a joining spigot 4 able to drive the slide rack 3 after a certain closing travel of the handle 2. A spring 6 is fitted between the slide rack 3 and the case 1 to return the slide rack 3 to the rest position. According to the embodiment of figures 9 to 15, the indicating means M comprises the same elements as previously described, but the indicator 5 articulated around the fixed axis 9 comprises a first end 5a cooperating with the retaining means 3 and a second end 5b connected to the core 8 of the electromagnet 11, so that the indicator 5 is driven by the core 8 in the tripping direction and moves in rotation with respect to said core when resetting of the latter takes place. According to this embodiment, the indicating means M comprises in addition a spring 12 able to return the flag 16 to a rest position after a closing operation of the contacts. Operation of the device of the invention will be described hereafter successively for the two embodiments: According to the first embodiment, the circuit breaker D being dosed (figs. 1 and 3), the circuit breaker and differential mechanisms are locked and the flag 16 is cleared, i.e. not visible through the window 13, as it is held in position by the part 7 itself retained by the core 8 of the differential tripping system. When a differential fault occurs, figure 2, and due to the tripping force given by the core 8 (arrow A), the indicator 5 and flag 16 pivot around the axis 9. The handle 2, released from latching on the circuit breaker side and equipped with the joining part 4, acts on a mechanfsm which drives the slide rack 3 which, due to the material clearance 15 when moving from left to right (arrow B), locks the spigot 14 of the indicator flag and thus secures it in the "visible" position (figure 2 and figure 4). When the apparatus is reset, the spring 10 of the electromagnet 11 pushes the core 8 to the rear position and thus resets the differential assembly to the work position. The action of the return spring 6 pushes the slide rack 3 to the rear position and thus unlocks the flag 16. The apparatus is then in the working position and able to fulfill its purpose. According to the second embodiment, the circuit breaker D being closed, figure 9, the circuit breaker and differential mechanisms are locked and the flag 16 is cleared. When a differential fault oocurs, figs 10 and 11, and due to the effect of the tripping force given by the core 8 (arrow A), the indicator 5 and therefore the flag 16 pivots around the axis 9. The handle 2, released from latching on the circuit breaker side and equipped with the joining part or spigot 4, drives the slide rack 3 which, moving from left to right (arrow B), locks the spigot 14 of the indicator flag 16 and thus secures it in the "visible" position. Unlike the first embodiment, the core 8 then returns to its initial position as soon as the circuit breaker is open (not visible, which is made possible by the fact that the indicator 5 can move in rotation with respect to the core 8 in this direction). When resetting (or closing) of the apparatus takes place, the return spring 6 pushes the slide rack 3 to the rear position and unlocks the indicator flag 16. The spring 12 then urges the flag 16 to return to its masked position. The apparatus is then in the working position and able to fulfill its purpose. It can be noted that the window 13 has in addition the function of protecting the internal mechanisms against foreign bodies getting in from outside. The technical advantages from the user standpoint are the following; The indicator flag operates independently from the power supply source of the electrical installation which the circuit breaker protects : it is mechanical. This results in enhanced safety for the user. Indeed, separation of the line-side and toad-side circuits is guaranteed under atl circumstances ; the differential fault information is reliable whatever the state of the source ; insulation of the user is guaranteed and the information is in all cases stored in memory. The indication is cleared by the simple closing operation of the circuit breaker by the user (certain devices require an action in two stages). The intrinsic technical advantages of the invention are the following: The stress exerted on the differential tripping relay is low and therefore does not reduce the reliability of the protection. The drive force of the indicating means is in fact low and the operating frictions are reduced. Returning the circuit breaker differential and resetting functions to the initial state are independent from initialisation of the indication. The functional mechanical links between the differential function, the circuit breaker tripping device and the differential fault indication function are in fact achieved in such a way that their initialisations are independent. The presence of the window made of transparent material enables the apparatus to be protected against external interventions. It does not enable dust and other pollution to get inside the apparatus and any external intervention on operation of the indicator flag and thence on the tripping relay is not possible. It can be noted that fitting of the mechanism is made easy by appropriate devices. One device enables the indicator flag spring to be held in a stable position during assembly and a second enables aytomatic fitting of this spring in the functional position when the differential function cover is fitted. Another device enables the sfide rack spring to be secured during its installation in the apparatus. It can finally be noted that according to the two embodiments, the indicating means is self-resettable, due to the electromagnet spring in the case of the first embodiment, or due to the spring associated to the indioator for the second embodiment. Naturally the invention is not limited to the described and illustrated embodiments which have been given for example purposes only. Thus the invention can be applied to any system-powered switchgear apparatus, with an auxiliary source or others requiring an electrical fault tndicating means whatever it be. Likewise, although the device of the invention is particularly suitable when the electromagnet used is of the plunger core type and therefore with temporary action, it would also be possible to apply the concept set Out in claim 1 and 2 to a switchgear apparatus using a refay of the magnetic latching type. The invention comprises all the technical equivalents of the means described and combinations thereof if the latter are performed within the spirit of the invention. We claims 1. A device for indicating an electrical fault in a breaking device such as a differential switch comprising: - a pair of separable contacts per pole, in electrical connection with a pair of connection terminals, - a contact operating mechanism, comprising a handle connected by a mechanical transmission link to a drive part of the contacts, - a trip device comprising a means for detecting an electrical fault and a tripping means such as an electromagnet able to bring about opening of the contacts when automatic tripping occurs following a fault, and - a means for indicating the tripped state of the switchgear apparatus, comprising an indicator able to occupy either a first inactive stable position or a second active stable position indicating the fault due to the action of the electromagnet, characterized in that it comprises a means (3), driven by the handle (2), for holding the indicator in the above-mentioned second position against the action of a means (10, 12) for returning said indicator (5) to the first position, so as to store the tripping information until a closing operation of the apparatus is performed. 2. The device according to claim 1, characterized in that the indicator (5) is driven positively by the electromagnet (11) between the two above-mentioned positions. 3. The device according to claim 1 or 2, characterized in that the above-mentioned tripping means (11) is an electromagnet with a plunger core (8) and the indicator (5) is driven positively by the plunger core (8) between the two above-mentioned positions. 4. The device according to any one of the foregoing claims, characterized in that the means for holding the indicator (5) comprises a slide rack (3) driven in translation by the handle (2) between a rest position and a position holding the indicator (5) in the second position. 5. The device according to any one of the foregoing claims, characterized in that the indicator (5) is mounted rotating around a fixed axis (9) of the apparatus, is connected in articulated manner via one of its ends to the core (8) of the electromagnet (11), and cooperates via its other end with the means (3) for holding the indicator (5). 6. The device according to any one of the claims 1 to 4, characterized in that the indicator (5) is articulated around a fixed axis (9) of the apparatus, and comprises a first end (5a) cooperating with the means for holding (3) and a second end (5b) connected to the core (8) of the electromagnet (11), in such a way that the indicator (5) is driven by the core (8) in the tripping direction and moves in rotation with respect to said core when resetting of the latter takes place. 7. The device according to claim 6, characterized in that the indicator (5) comprises in addition a spring (12) able to return the indicator (5) to the rest position after the apparatus has been reset. 8. The device according to any one of the claims 4 to 7, characterized in that the indicating means M comprises a spring (6) fitted between the slide rack (3) and the case and able to return the slide rack (3) to the rest position when resetting of the apparatus takes place. 9. The device according to any one of the claims 4 to 8, characterized in that the handle (2) comprises a spigot (4) designed to operate in conjunction with the slide rack (3) so as it drive it after a certain travel when automatic tripping takes place, and not to drive it during a closing operation. 10. The device according to any one of the claims 5 to 9, characterized in that the indicator (5) comprises a spigot (14) operating in conjunction with a material clearance (15) arranged in the slide rack (3). 11. The device according to any one of the claims 4 to 10, characterized in that the indicator (5), on the side where the slide rack (3) is situated, comprises a flag (16) designed to cooperate with a window (13) provided in the case. 12. A switchgear apparatus equipped with a device according to any one of the foregoing claims. 13. The apparatus according to claim 12, characterized in that it has an auxiliary source. 14. A differential circuit breaker according to claim 12 or 13 characterized in that the device is used to detect an insulation fault. 15* A device for Indicating an electrical fault in a breaking device substantially as herein described with reference to the accompanying drsviggs*

Documents:

1827-mas-1998-abstract.pdf

1827-mas-1998-claims duplicate.pdf

1827-mas-1998-claims original.pdf

1827-mas-1998-correspondence others .pdf

1827-mas-1998-correspondence po.pdf

1827-mas-1998-description complete duplicate.pdf

1827-mas-1998-description complete original.pdf

1827-mas-1998-drawings.pdf

1827-mas-1998-form 1.pdf

1827-mas-1998-form 26.pdf

1827-mas-1998-form 3.pdf

1827-mas-1998-form 4.pdf