EP0866484A2 - Magnetothermal low voltage circuit breaker with sensitive element made from shape-memory material - Google Patents
Magnetothermal low voltage circuit breaker with sensitive element made from shape-memory material Download PDFInfo
- Publication number
- EP0866484A2 EP0866484A2 EP97203780A EP97203780A EP0866484A2 EP 0866484 A2 EP0866484 A2 EP 0866484A2 EP 97203780 A EP97203780 A EP 97203780A EP 97203780 A EP97203780 A EP 97203780A EP 0866484 A2 EP0866484 A2 EP 0866484A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- shape
- memory material
- magnetothermal
- circuit breaker
- low voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
- H01H71/10—Operating or release mechanisms
- H01H71/12—Automatic release mechanisms with or without manual release
- H01H71/14—Electrothermal mechanisms
- H01H71/145—Electrothermal mechanisms using shape memory materials
Definitions
- the present invention relates to a magnetothermal low voltage circuit breaker with sensitive element made from shape-memory material.
- magnetothermal low voltage circuit breakers are made with two separate trip devices, more precisely a thermal trip device that is time-dependent and trips in the event of a current overload and a time-independent or instantaneous electromagnetic trip device which trips in the event of short-circuit.
- the thermal trip device is made with a bimetallic strip which exhibits considerable limits of applicability, on account of its poor versatility for being adapted to protection for the various uses.
- thermal trip device is made from a shape-memory material which is used instead of the bimetallic strip and which is normally obtained from NiTi alloys or alloys based on CuNiTi which are made with different structural configuration.
- the current passes through the shape-memory material and when the current exceeds the rated value, the overheating produced by the Joule effect on the material heats it above the temperature of activation (or phase-transition) in a time which depends on the magnitude of the current, so that the circuit is opened.
- shape-memory materials generally have transition temperatures which close to ambient temperature; it is therefore difficult to guarantee that operation is always efficient and correct.
- the task addressed by the invention is precisely that of eliminating the above undesirable drawbacks, by making a magnetothermal low voltage circuit breaker with sensitive element made from shape-memory material which affords the possibility of considerably simplifying all the constructional aspects, without having the need to provide devices for protection against short-circuit currents.
- a particular objective of the invention is that of making a thermal trip device which is very stable, having an activation temperature considerably above ambient temperature.
- Another objective of the present invention is that of making a magnetothermal circuit breaker in which the thermal trip device is able to afford the widest guarantees of reliability and safety during use.
- the said thermal trip device consisting of an element made from shape-memory material, characterised in that the said shape-memory material exhibits a temperature of transition between the martensite phase and the austenite phase of greater than 90°C and a thermal shock resistance temperature of greater than 600°C.
- the magnetothermal low voltage circuit breaker which is denoted in its entirety by the reference number 1, comprises a boxlike body 2 with a configuration which is known per se, inside which is provided a coil 3 traversed by the current and operationally interconnected with a magnetic trip device 4 which acts on the trigger device 5 of the circuit breaker, opening the contacts and breaking the flow of current.
- a thermal trip device 10 which, in the embodiment shown in Figure 1, consists of a strip made from shape-memory alloy which is represented under rest conditions in the martensite phase.
- the shape-memory material strip is to modify its shape so that a portion of it acts on the trigger mechanism of the circuit breaker.
- the shape-memory alloy is subject to phase transition to the austenite phase and the strip returns to an initial memorised curved shape in which the left end, referring to the drawing, is raised and acts on the opening mechanism.
- An important novel feature of the invention consists in the fact that the alloy used exhibits a temperature of transition between the martensite phase and the austenite phase which is greater than 90°C and has a thermal shock resistance temperature which is greater than 600°C.
- a preferred but non-limiting embodiment provides for the use of an alloy based on hafnium; more specifically, in a prefered formulation thereof, the alloy consists of nickel from 30 to 51%, titanium from 20 to 66.5% and hafnium from 3.5 to 40% as, for example, explained in patent US 5114504.
- the device can also be provided with a system for restoring the shape typical of the rest condition when the shape-memory material has reverted to the martensite phase; the restoring mechanism can be incorporated within the manual resetting mechanism of the circuit breaker, thus further increasing the compactness of the circuit breaker.
- the thermal trip device described above can be provided with external means of restoring the typical rest shape in the martensite phase such as for example return springs or the like, or can be made in such a way that the material recovers its typical rest shape at the change of phase (austenite to martensite), so that the material is defined as having a 2-way shape memory.
- the shape-memory material instead of acting directly on the trigger mechanism, acts on an actuator which can engage with the trigger mechanism.
- the thermal trip device is able to adopt a first configuration in which it latches the actuator, and a second configuration in which it unlatches the actuator.
- the shape-memory material thermal trigger element made with an alloy containing hafnium, provides for a retention device referenced with 20, which under rest conditions exhibits a contracted configuration so that an actuating actuator 21, thrust by a spring 22, counteracts with it.
- the deformable element 20 changes its shape by expanding and allows the movement of the actuator 21 which thrust by the spring passes through the retention device and interacts with the trigger mechanism.
- the retention device 20 is a shape-memory alloy based ring whose internal diameter in the austenite phase is greater than the external diameter of the actuator 21.
- the element 20 In the rest condition (Fig. 2) the element 20 is in the martensite phase and has a contracted configuration.
- the activated condition (Fig. 3) the element 20 In the activated condition (Fig. 3) the element 20 is in the austenite phase and has recovered its memorised configuration thus unlatching the actuator 21.
- the plunger is always subject to the thrust of the spring, so that when the deformable shape-memory element 20 is subject to phase transition to the austenite phase said element 20 recovers its memorised configuration, thus unlatching the actuator (or plunger) that interacts with the trigger mechanism.
- the invention allows considerable improvements to be made to thermal trip devices for magnetothermal circuit breakers, overcoming all the drawbacks associated both with bimetallic strips and with existing devices made from shape-memory alloy, by using a particular shape-memory alloy based on hafnium which allows a transition phase which is very far from ambient temperature and moreover allows a particularly high resistance to thermal shocks from short-circuit currents, so that it does not suffer irreversible damage.
Abstract
Description
Claims (9)
- A magnetothermal low voltage circuit breaker with sensitive element made from shape-memory material comprising a coil traversed by current and operationally interconnected with a magnetic trip device for instantaneously breaking the flow of current for short-circuit and a thermal trip device for breaking the flow of current for overload, the said thermal trip device consisting of an element made from shape-memory material, characterised in that the said shape-memory material exhibits a temperature of transition between the martensite phase and the austenite phase of greater than 90°C and a thermal shock resistance temperature of greater than 600°C.
- A magnetothermal low voltage circuit breaker according to claim 1, characterised in that the shape-memory material is an alloy containing hafnium.
- A magnetothermal low voltage circuit breaker according to any of the preceding claims, characterised in that the said shape-memory material is an alloy containing nickel, titanium and hafnium.
- A magnetothermal low voltage circuit breaker according to one or more of the preceding claims, characterised in that the said shape-memory material is an alloy containing nickel from 30 to 51% titanium from 20 to 66.5% and hafnium from 35 to 40%.
- A magnetothermal low voltage circuit breaker according to one or more of the preceding claims, characterised in that the said thermal trip device comprises a strip made from the said shape-memory material and able to modify its shape so that a portion of it acts on the trigger mechanism of the said magnetothermal circuit breaker.
- A magnetothermal low voltage circuit breaker according to one or more of the preceding claims, characterised in that the said thermal trip device made from shape-memory material acts on an actuator which can engage with the trigger mechanism, the said thermal trip device being able to adopt a first configuration in which it latches the said actuator, and a second configuration in which it unlatches the said actuator.
- A magnetothermal low voltage circuit breaker according to claim 6, characterised in that the said thermal trip device comprises a shape memory alloy retention device which, in a first contracted configuration, latches the said actuator, and in a second expanded configuration, in unlatches the said actuator.
- A magnetothermal low voltage circuit breaker according to one or more of the preceding claims, characterised in that it comprises a mechanism for restoring the shape typical of the rest condition of the thermal trip device made from the said shape-memory material, said mechanism being incorporated within the resetting mechanism of the circuit breaker.
- A magnetothermal low voltage circuit breakers according to one or more of the preceding claims, characterised in that it comprises a mechanism for restoring the original shape of the thermal trip device made from shape-memory material, said mechanism being obtained from a 2-way shape-memory material able to restore its typical shape under rest conditions upon the return to the temperature corresponding to the martensite phase.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ITMI962530 | 1996-12-03 | ||
IT96MI002530A IT1286425B1 (en) | 1996-12-03 | 1996-12-03 | LOW VOLTAGE MAGNETOTHERMAL SWITCH WITH SENSITIVE ELEMENT MADE OF SHAPE MEMORY MATERIAL |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0866484A2 true EP0866484A2 (en) | 1998-09-23 |
EP0866484A3 EP0866484A3 (en) | 1999-03-10 |
Family
ID=11375332
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP97203780A Withdrawn EP0866484A3 (en) | 1996-12-03 | 1997-12-03 | Magnetothermal low voltage circuit breaker with sensitive element made from shape-memory material |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0866484A3 (en) |
IT (1) | IT1286425B1 (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2002013220A1 (en) * | 2000-08-04 | 2002-02-14 | Siemens Aktiengesellschaft | Switching device with a component consisting of a shape memory alloy and with means for heating the same; and corresponding joining technique |
US6603386B2 (en) | 2000-06-22 | 2003-08-05 | Alcatel | Bi-stable microswitch including shape memory alloy latch |
WO2006056335A1 (en) * | 2004-11-22 | 2006-06-01 | Abb Patent Gmbh | Switching equipment comprising an electromagnetic trip device |
DE102010014280A1 (en) * | 2010-04-08 | 2011-10-13 | Eto Magnetic Gmbh | Overcurrent switching device |
EP2472548A1 (en) * | 2010-12-30 | 2012-07-04 | General Electric Company | Shape memory alloy actuated circuit breaker |
CN114792613A (en) * | 2022-03-30 | 2022-07-26 | 中群电气有限公司 | Overload quick recovery circuit breaker |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5061914A (en) * | 1989-06-27 | 1991-10-29 | Tini Alloy Company | Shape-memory alloy micro-actuator |
EP0484805A1 (en) * | 1990-11-05 | 1992-05-13 | Johnson Service Company | High transformation temperature shape memory alloy |
-
1996
- 1996-12-03 IT IT96MI002530A patent/IT1286425B1/en active IP Right Grant
-
1997
- 1997-12-03 EP EP97203780A patent/EP0866484A3/en not_active Withdrawn
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5061914A (en) * | 1989-06-27 | 1991-10-29 | Tini Alloy Company | Shape-memory alloy micro-actuator |
EP0484805A1 (en) * | 1990-11-05 | 1992-05-13 | Johnson Service Company | High transformation temperature shape memory alloy |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6603386B2 (en) | 2000-06-22 | 2003-08-05 | Alcatel | Bi-stable microswitch including shape memory alloy latch |
WO2002013220A1 (en) * | 2000-08-04 | 2002-02-14 | Siemens Aktiengesellschaft | Switching device with a component consisting of a shape memory alloy and with means for heating the same; and corresponding joining technique |
WO2006056335A1 (en) * | 2004-11-22 | 2006-06-01 | Abb Patent Gmbh | Switching equipment comprising an electromagnetic trip device |
DE102010014280A1 (en) * | 2010-04-08 | 2011-10-13 | Eto Magnetic Gmbh | Overcurrent switching device |
US8860534B2 (en) | 2010-04-08 | 2014-10-14 | Eto Magnetic Gmbh | Overcurrent switching device |
DE102010014280B4 (en) | 2010-04-08 | 2021-11-25 | Eto Magnetic Gmbh | Overcurrent switching device |
EP2472548A1 (en) * | 2010-12-30 | 2012-07-04 | General Electric Company | Shape memory alloy actuated circuit breaker |
CN102568955A (en) * | 2010-12-30 | 2012-07-11 | 通用电气公司 | Shape memory alloy actuated circuit breaker |
US8830026B2 (en) | 2010-12-30 | 2014-09-09 | General Electric Company | Shape memory alloy actuated circuit breaker |
CN102568955B (en) * | 2010-12-30 | 2016-01-20 | 通用电气公司 | The circuit breaker of shape memory alloy actuated |
CN114792613A (en) * | 2022-03-30 | 2022-07-26 | 中群电气有限公司 | Overload quick recovery circuit breaker |
CN114792613B (en) * | 2022-03-30 | 2023-07-25 | 中群电气有限公司 | Overload quick recovery circuit breaker |
Also Published As
Publication number | Publication date |
---|---|
EP0866484A3 (en) | 1999-03-10 |
ITMI962530A1 (en) | 1998-06-03 |
ITMI962530A0 (en) | 1996-12-03 |
IT1286425B1 (en) | 1998-07-08 |
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