GB2453861A

GB2453861A - Circuit breaker

Info

Publication number: GB2453861A
Application number: GB0819013A
Authority: GB
Inventors: Johann Herrmann; Gerald Noerl; Bernhard Schmid
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2007-03-01
Filing date: 2008-03-03
Publication date: 2009-04-22
Anticipated expiration: 2028-03-03
Also published as: GB0819013D0; DE102007063636A1; GB2447147A; GB2453861B; GB0803962D0; GB2447147B; CN101256918A; DE102007010015A1

Abstract

With fault current circuit breakers or differential current circuit breakers, a test key is often used in the prior art to close a test current circuit so that a test current, which simulates a fault current, flows and a check as carried out to determine whether the circuit breaker functions in a proper manner. In accordance with the invention, a test lever element (16) is used instead of a test key. This is pivoted about the same axis of rotation as the conventionally provided opening/closing control lever (12) of the circuit breaker, and the movement of the test lever element (16) can be partially coupled to this control lever (12). A surface of the test lever element which can be manipulated by the operator has the same cross-sectional profile as that of the surface of the control lever which can be manipulated by the operator. In a predetermined position of the test lever element (16), the test current circuit is closed. This predetermined position is preferably an intermediate position of the test lever element between two end positions, so that the test current only flows briefly.

Description

1 2453861 CIRCUIT BREA1ER The present invention relates to a fault current circuit breaker or a differential current circuit breaker as well as a combined instrument comprising a circuit breaker and a fault current circuit breaker or differential current circuit breaker.

Like a differential current circuit breaker, a fault current circuit breaker has the task of detecting a fault current.

The present invention addresses in particular a test function.

Within the scope of the test function, a test current is gen-erated, in particular by closing a test current circuit and a check is carried out to determine whether the circuit breaker reacts correctly to the test current, in the same way as it does to fault currents.

The test current circuit is usually closed by pressing a test key. Such a test key is described for instance in DE 102 20 622 Al and EP 1 492 140 Al. JP 2932242 B2 discloses arranging a test key directly adjacent to the closing/opening control lever. Circuit breakers usually have such a control lever. The arrangement of the test key is hence problematic because the installation space for the test key is restricted due to the control lever requiring a great deal of space. A user must have access both to the control lever and also to the test key. In addition, there must be room for a label, which has to be read by an operator.

FR 2648950 A3 discloses a circuit breaker with a test circuit operable by rotating a lever to an end position. This device has a rather complex construction.

The object of the invention is to provide a fault current cir- cult breaker, a differential current circuit breaker or a com-bined instrument comprising such a circuit breaker with a power circuit breaker, which has a test function, with the available space being used as effectively as possible.

The object is achieved by a fault current circuit breaker or a differential current circuit breaker as claimed in claim 1 and/or a combined instrument as claimed in claim 9.

In accordance with the invention, the circuit breaker has a test lever element which can be pivoted between a first end position and a second end position by an operator, where, with a predetermined position of the test lever element, a test current circuit is closed and a test current which simulates a fault current flows. The test lever element is pivoted about the same axis of rotation as the closing/opening control lever of the fault current circuit breaker or differential current circuit breaker. A surface of the test lever element which can be manipulated by the operator has the same cross-sectional profile as that of the surface of the control lever which can be manipulated by the operator.

The invention may not therefore depend on using a test key. As a result of an opening/closing control lever in any case being provided, the test lever element which can be manipulated and actuated by an operator can be arranged suitably in respect of this control lever. While it was problematic in the prior art that the test key could be inadvertently pressed when actuat-ing the control lever, if it is located in its vicinity, such problems do not exist with the test lever element, and the circuit breaker can be designed in a compact fashion.

With a preferred embodiment, the predetermined position of the test lever element, in which the test current circuit is closed, is an intermediate position of the test lever element between the two end positions. With this embodiment, it is consciously accepted that the predetermined position of the test lever element is only briefly assumed when forcing the same from one of its end positions to the other of its end po-sitions. It is however fully adequate for the test function if the test current only flows for a brief moment.

With a preferred embodiment, a stirrup engages with the test lever element, namely at a position which is distanced from an axis of rotation of the test lever element. In the predeter-mined position, the stirrup bridges two contact elements or alternatively acts on a pushbutton switch in the predetermined position.

The stirrup can be completely subjected to the force of grav-ity, so that an end of the stirrup opposite the test lever element hangs freely. Furthermore, the end of the stirrup op-posite the test lever element may be guided by one or more guide-rails. The guide-rails may guide the end of the stirrup opposite the test lever element in a substantially vertical plane, whilst the end of the stirrup engaged to the test lever element rotates with the test lever element. If the test lever element is rotated, the predetermined position of the test lever element is then preferably that in which the posi-tion, with which the stirrup engages, reaches its lowest point. The stirrup end then also achieves its lowest point and can bridge the two contact elements. Accordingly, the end of the stirrup opposite the test lever element may comprise a conducting element or the entire stirrup may be a conducting material, for example a metal. Alternatively, the stirrup may briefly exert force on the pushbutton switch. If the test lever element is rotated further, the stirrup end again moves away from the contact elements and/or pushbutton switch, thereby breaking the electrical circuit.

As already mentioned, advantageous arrangements of the test lever element are enabled, which are not provided with a test key. The test lever element is pivoted about the same axis of rotation as the closing/opening control lever of the fault current circuit breaker or differential current circuit breaker and is herewith arranged particularly preferably di- rectly adjacent to the control lever. This preferred embodi-ment allows particularly compact design of the circuit breaker according to the invention.

This lends itself to the coupling of the actuation of the test lever element with that of the control lever in any manner.

As one measure, the first end position of the test lever ele-ment has the same angular position in respect of the axis of rotation as an OFF position of the control lever and the sec- ond end position of the test lever element has the same angu- lar position in respect of the axis of rotation as an ON posi-tion of the control lever. In other words, the pivoting range of the test lever element is identical to the pivoting range of the control lever, which enables the two to be coupled to-gether.

A coupling of the test lever element and control lever is also facilitated in that a surface of the test lever element which can be manipulated by the operator has the same cross-sectional profile as that of the surface of the control lever which can be manipulated by the operator. If the test lever element is arranged directly adjacent to the control lever, this means that a quasi continuous handle region is formed and that the test lever element and control lever can be simulta-neously manipulated and activated in a particularly simple fashion.

The coupling between the test lever element and the control lever can also be carried out by means of a driving element.

The driving element can be embodied for instance such that only the test lever element has to be pivoted from its first end position into a second end position and the control lever is automatically moved therewith from its OFF position into its ON position. A driving element and in particular the same driving element can also cause the test lever element to move into its first end position (from its second end position) when the control element is pivoted from its ON position into its OFF position.

The latter measure prevents the test lever element from pivot-ing provided the circuit breaker remains closed. This is quite expedient since test currents are not to flow when the circuit breaker is switched off. Instead, it is then only expedient to allow the test current to flow if the control lever is in its ON position.

A preferred embodiment of the invention is described below with reference to the drawings, in which; FIG 1 shows a perspective interior view of a fault current circuit breaker according to the invention, in which the control lever and the test lever element are both in the OFF position, FIG 2 shows the fault current circuit breaker from FIG 1 in the situation in which the control lever and the test lever element are in the ON position, FIG 3 shows a cross-sectional view through the fault current circuit breaker from FIG 1, in which the control lever is in the ON position and the test lever element is in such a position that a test current circuit is closed, FIG 4 shows a perspective view of the fault current circuit breaker from FIG 1 in the situation in that the control lever is in the ON position and the test lever element is in the OFF position, FIG 5 shows a cross-sectional view of the situation from FIG 4 without the control lever, FIG 6 shows a perspective view of the test lever element used in the invention, FIG 7 shows a perspective view of the control lever used in the invention.

A fault current circuit breaker designated in its entirety with 10 conventionally has a control lever 12, with the aid of which the fault current circuit breaker can be closed and opened. The control lever 12 is shown in its entirety in FIG 7. It interacts with other components of the fault current circuit breaker by way of a transfer rod 14, which is not shown in FIG 1, because the functionality of the control lever 12 in this respect does not differ from the prior art.

A test lever element 16 is arranged directly adjacent to the control lever 12. The test lever element 16 can be pivoted about the same axis of rotation as the control lever 12. It is shown in its entirety in FIG 6. The control lever 12 has a grip surface 18 which can be manipulated by an operator. The test lever element 16 has a similar grip surface 20, which has precisely the same cross-sectional profile as the grip surface 18. The grip surface 20 joins directly with the grip surface 18 and lengthens this in a direction parallel to the axis of rotation of the control lever 12 and the test lever element 16. The control lever 12 and test lever element 16 can thus be pivoted with one another in a particularly effective manner.

This joint pivoting action is to take place in particular be-tween the OFF position of the control lever 12 shown in FIG 1 and the ON position of the control lever 12 shown in FIG 2. To facilitate the coupled movement, the control lever 12 has a projection 2 shown in FIG 7 on an annular base body 22, which could also be referred to as a stud. A partial ring 26 embod-ied on the test lever element 16 is narrower than the annular base body 22 of the control lever, which allows the projection 24 to engage below the partial ring 26. A second partial ring 28 of the test lever element 16 which joins the partial ring 26 is however wider, for instance as wide as the annular base body 22 of the control lever 12. A driving edge 30 is herewith provided. If the test lever element 16 is pivoted, the driving edge 30 acts on the projection 24, so that the control lever 12 is forcedly pivoted together with the test lever element.

With the changeover from the situation according to FIG 1 to the situation according to FIG 2, the operator must essen-tially thus exclusively actuate the test lever element 16, and the control lever 12 rotates therewith.

If the control lever 12 automatically snaps back from the ON position into its OFF position, when a fault current exists, it also for its part drives the test lever element 16 back-wards in this direction. This is however expedient because the test lever element 16 is to revert back to the basic position if the fault current circuit breaker 10 is switched off.

The projection 24 does not prevent the test lever element 16 from being able to pivot back in the direction of the OFF po-sition of the control lever independently of the control lever 12. J\ test current circuit can be closed with this pivoting process. This takes place with the aid of a metal stirrup 32.

The metal stirrup 32 can be seen particularly well in FIG 1.

It engages with a recess 34 of the test lever element 16 shown in FIG 6, with this engagement process also being shown in FIG and FIG 3. The recess 34 is positioned such that the stirrup 32 in the OFF position of the test lever element 16 does not touch two contact elements 36 and 36' and that also in the ON position, which can be seen in FIG 2, it does not touch the contact elements 36 and 36' such that in an intermediate posi-tion shown in FIG 3, it bridges the two contact elements 36 and 36' with its free end and herewith closes the test current circuit so that a test current is able to flow. When the test lever element is pivoted backwards from the ON position into the OFF position, a test current thus flows briefly. The du-ration of the test current flow is sufficiently long to test the functionality of the fault current circuit breaker.

The test current would however flow permanently if it was es-sentially also possible for the contacts 36 and 36' to be bridged in the OFF position of the test lever element 16. It is thus advantageous for the constructive measure to prevent a permanent flow of the test current such that the contact ele- ments 36 and 36' are bridged by the stirrup 32 only in an in-termediate position which is not permanently taken up by the test lever element 16.

Whereas test keys are used in the prior art to close the test current circuit, the use of the test lever element 16 is ad-vantageous in that the space otherwise available exclusively to the control lever is used optimally for two elements.

Problems with the arrangement of a test key do not apply as a result and the fault current circuit breaker can be con- structed in a particularly compact manner. There is suffi- cient space available for labels which are visible to an op-erator.

Claims

CLAIMS: 1. A fault current circuit breaker or differential-current circuit breaker, with a test lever element which can be piv-oted between a first end position and a second end position by an operator, with a test current circuit being closed when the test lever element is in a predetermined position, such that a test current, which simulates a fault current, flows; wherein the test lever element can be pivoted about the same axis of rotation as an opening/closing control lever of the fault current or differential current circuit breaker; and wherein a surface of the test lever element which can be manipu-lated by the operator has the same cross-sectional profile as a surface of the control lever which can be manipulated by the operator.
2. The fault current or differential current circuit breaker as claimed in claim 1, characterized in that the predetermined position of the test lever element is an intermediate position of the test lever element between the first end position and the second end position.
3. The fault current or differential current circuit breaker as claimed in claim 1 or 2, characterized in that a stirrup engages with the test lever element at a point which is dis-tanced from an axis of rotation of the test lever element, said stirrup causing the completion of an electrical circuit between two contact elements when the test lever element is in the predetermined position.
4. The fault current or differential current circuit breaker as claimed in claim 3, characterized in that the stirrup is an electrical conductor and forms part of the electrical circuit between the two contact elements when the test lever element is in the predetermined position.
5. The fault current or differential current circuit breaker as claimed in claim 3, characterized in that the stirrup acts on a push button switch arranged between the live contact ele- ments, such that the electrical circuit between the two con-tact elements is completed when the test lever element is in the predetermined position.
6. The fault current or differential current circuit breaker as claimed in any of the preceding claims, characterized in that the first end position of the test lever element has the same angular position in respect of the axis of rotation as an OFF position of the control lever and the second end position of the test lever element has the same angular position in re-spect of the axis of rotation as an ON position of the control lever.
7. The fault current or differential current circuit breaker as claimed in any of the preceding claims, characterized in that a driving element effects a movement of the control lever from its OFF position into its ON position by pivoting the test lever element from the first end portion into the second end position.
8. The fault current or differential current circuit breaker as claimed in any of the preceding claims, characterized in that a driving element causes the test lever element to move into its first end position when the control lever is pivoted from its ON position into its OFF position.
9. A combined instrument comprising a circuit breaker and a fault current or differential current circuit breaker as claimed in any of the preceding claims.
10. A fault current or differential circuit breaker substan-tially as described herein with reference to and as shown in the accompanying drawings.
11. A combined instrument comprising a circuit breaker and a fault current or differential circuit breaker substantially as described herein with reference to and as shown in the accom-panyirig drawings.