TRIPPING DEVICE FOR A CIRCUIT BREAKER

Abstract

A trip device for a power circuit breaker has a trip element, a trip circuit with a trip coil, which, when energized, is configured to effect a movement of the trip element, and at least one electrical delay element, which can be connected to the trip circuit and reduces the rate of a rise in a current flowing in the trip coil once the trip circuit has been closed and/or delays a rise in a current flowing in the trip coil once the trip circuit has been closed.

Claims

1-15. (canceled)

16. A tripping device for a circuit breaker, the tripping device comprising: a tripping element; a tripping circuit having a tripping coil being configured, upon being energized, to effect a movement of said tripping element; and at least one electrical delay element being able to be connected to said tripping circuit and reducing a steepness of a current increase of a current flowing in said tripping coil after said tripping circuit has been closed and/or delays the current increase of the current flowing in said tripping coil after said tripping circuit has been closed.

17. The tripping device according to claim 16, wherein said at least one electrical delay element includes a delay coil that is able to be connected in series with said tripping coil.

18. The tripping device according to claim 17, wherein an ohmic resistance of said delay coil is lower than an ohmic resistance of said tripping coil.

19. The tripping device according to claim 17, further comprising a magnetic core, around which a winding of said delay coil runs.

20. The tripping device according to claim 19, wherein said magnetic core is disposed so as to be displaceable with respect to said delay coil, with a result that an inductance of said delay coil is able to be changed.

21. The tripping device according to claim 17, wherein a number of turns of said delay coil, in said turns electric current flows when said tripping circuit is closed, is settable.

22. The tripping device according to claim 21, wherein said delay coil has a plurality of taps or an adjustable tap in order to set the number of turns.

23. The tripping device according to claim 17, further comprising an electrical resistor connectable in series with said tripping coil and said delay coil and functioning as a further delay element.

24. The tripping device according to claim 16, wherein said at least one electrical delay element includes a capacitor that is able to be connected in parallel with said tripping coil.

25. The tripping device according to claim 16, wherein said at least one electrical delay element includes a capacitor and an electrical resistor, wherein a series connection of said capacitor and said electrical resistor is connectable in parallel with said tripping coil.

26. The tripping device according to claim 25, wherein said electrical resistor has a settable ohmic resistance.

27. The tripping device according to claim 26, wherein said capacitor has a settable capacitance.

28. The tripping device according to claim 16, further comprising a common housing, said tripping coil and said at least one electrical delay element are disposed in said common housing.

29. The tripping device according to claim 23, wherein said electrical resistor has a settable ohmic resistance.

30. The tripping device according to claim 24, wherein said capacitor has a settable capacitance.

31. A circuit breaker, comprising: a tripping device according to claim 16, said tripping device is configured to trigger a switching process of the circuit breaker.

32. A method for increasing a tripping time of a tripping device for a circuit breaker, the tripping device having a tripping element and a tripping circuit with a tripping coil being configured, upon being energized, to affect a movement of the tripping element, which comprises the step of: connecting at least one electrical delay element to the tripping circuit for reducing a steepness of a current increase of a current flowing in the tripping coil after the tripping circuit has been closed and/or delays the current increase of the current flowing in the tripping coil after the tripping circuit has been closed.

Description

[0029] FIG. 1 shows a schematic illustration of a first exemplary embodiment of a tripping device,

[0030] FIG. 2 shows a circuit diagram of the tripping device shown in FIG. 1,

[0031] FIG. 3 shows a schematic illustration of a second exemplary embodiment of a tripping device,

[0032] FIG. 4 shows a schematic illustration of a third exemplary embodiment of a tripping device,

[0033] FIG. 5 shows a schematic illustration of a fourth exemplary embodiment of a tripping device,

[0034] FIG. 6 shows a circuit diagram of the tripping device shown in FIG. 5,

[0035] FIG. 7 shows a schematic illustration of a fifth exemplary embodiment of a tripping device,

[0036] FIG. 8 shows a circuit diagram of a sixth exemplary embodiment of a tripping device,

[0037] FIG. 9 shows a circuit diagram of a seventh exemplary embodiment of a tripping device,

[0038] FIG. 10 shows a circuit diagram of an eighth exemplary embodiment of a tripping device.

[0039] In the figures, parts corresponding to one another have been provided with the same reference signs.

[0040] FIGS. 1 and 2 (FIG. 1 and FIG. 2) show a first exemplary embodiment of a tripping device 1, according to the invention, for a circuit breaker. FIG. 1 shows a schematic illustration of the tripping device 1, FIG. 2 shows a circuit diagram of the tripping device 1.

[0041] The tripping device 1 comprises a tripping element 3 and a tripping circuit comprising a tripping coil 5 that is designed, upon being energized, to effect a movement of the tripping element 3, and a switching element 7, using which the tripping circuit can be opened and closed (the switching element 7 is not illustrated in FIG. 1). The tripping device 1 also comprises a delay coil 9 that is able to be connected to the tripping circuit by way of a changeover switch 11. FIG. 1 shows a first switching position of the changeover switch 11 in which the changeover switch 11 connects the delay coil 9 in series with the tripping coil 5. In a second switching position, the changeover switch 11 bypasses the delay coil 9, and so the delay coil 9 is not in the current path of the tripping circuit.

[0042] A winding of the tripping coil 5 runs around a first magnetic core 13. The first magnetic core 13 annularly surrounds a section of the tripping element 3. The tripping element 3 has a ferromagnetic magnet armature. If the tripping circuit is closed by the switching element 7, an electric current flowing in the tripping coil 5 generates a magnetic field, by way of which the tripping element 3 is moved. The tripping element 3 moved by the magnetic field releases a switch drive that drives at least one switching contact element of the circuit breaker after being released. By way of example, for this purpose, the tripping element 3 releases a latching element that inhibits a movement of the at least one switching contact element.

[0043] The delay coil 9 has an ohmic resistance that is, for example, considerably lower than an ohmic resistance of the tripping coil 5 if the total power in the tripping circuit is intended to be as low as possible. A winding of the delay coil 9 runs around a second magnetic core 15.

[0044] If the delay coil 9 is connected into the tripping circuit by way of the changeover switch 11, in a time interval in which the current in the tripping circuit increases immediately after the tripping circuit has been closed, the inductive resistance of the delay coil 9 reduces a steepness of a current increase of a current flowing in the tripping coil 5 in comparison with the case in which the delay coil 9 is bypassed by the changeover switch 11. If the current in the tripping circuit stabilizes after a switch-on phase, the delay coil 9 influences the current intensity in the tripping circuit only slightly in comparison with the case in which the delay coil 9 is not connected in, provided that the ohmic resistance of the delay coil 9 is considerably lower than the ohmic resistance of the tripping coil 5 because the inductive resistance of the delay coil 9 only has a significant effect if the current intensity in the tripping circuit changes. Therefore, connecting in the delay coil 9 increases the tripping time of the tripping device 1, but hardly changes the force on the tripping element 3 caused by the magnetic field generated by the tripping coil 5 in comparison with the case in which the delay coil 9 is not connected to the tripping circuit.

[0045] The tripping coil 5, the delay coil 9, the magnetic cores 13, 15 and the tripping element 3 are arranged in a common housing 17, wherein an end section of the tripping element 3 protrudes from the housing 17 through a housing opening 19.

[0046] FIG. 3 (FIG. 3) shows a schematic illustration of a second exemplary embodiment of a tripping device 1, according to the invention, for a circuit breaker. This exemplary embodiment only differs from the exemplary embodiment shown in FIGS. and 2 in that the second magnetic core 15 is arranged so as to be displaceable with respect to the delay coil 9, with the result that an inductance of the delay coil 9 is able to be changed. In the exemplary embodiment shown in FIG. 3, the second magnetic core 15 is displaceable by way of an adjusting screw 21 that is connected to the second magnetic core 15, is guided on the housing 17 and protrudes from the housing 17. The ability of the second magnetic core 15 to be displaced means that the inductive resistance of the delay coil 9, and therefore the increase in the tripping time of the tripping device 1, are settable in comparison with the case in which the delay coil 9 is not connected to the tripping circuit.

[0047] FIG. 4 (FIG. 4) shows a schematic illustration of a third exemplary embodiment of a tripping device 1, according to the invention, for a circuit breaker. This exemplary embodiment only differs from the exemplary embodiment shown in FIGS. 1 and 2 in that the delay coil 9 has a plurality of taps 23 to 26 that are optionally contactable by way of a changeover switch 11. If the changeover switch 11 makes contact with a first tap 23 of the delay coil 9, the delay coil 9 is bypassed, and so said delay coil is not in the current path of the tripping circuit. If the changeover switch 11 makes contact with one of the other taps 24 to 26, a different number of turns of the delay coil 9, in which turns electric current flows when the tripping circuit is closed, is set in each case. In other words, a number of turns of the delay coil 9, in which turns electric current flows when the tripping circuit is closed, is settable by way of the changeover switch 11. By changing this number of turns, an inductance of the delay coil 9, and therefore the increase in the tripping time of the tripping device 1, are able to be changed and able to be set in comparison with the case in which the delay coil 9 is not connected to the tripping circuit.

[0048] FIGS. 5 and 6 (FIG. 5 and FIG. 6) show a fourth exemplary embodiment of a tripping device 1, according to the invention, for a circuit breaker. FIG. 5 shows a schematic illustration of the tripping device 1, FIG. 6 shows a circuit diagram of the tripping device 1.

[0049] The tripping device 1, like the exemplary embodiments shown in FIGS. 1 to 4, comprises a tripping element 3, a magnetic core 13 that annularly surrounds a section of the tripping element 3, a tripping circuit comprising a tripping coil 5 that has a winding running around the magnetic core 13 and is designed, upon being energized, to effect a movement of the tripping element 3, and a switching element 7, using which the tripping circuit can be opened and closed (the switching element 7 is not illustrated in FIG. 5). The tripping device 1 also comprises a capacitor 27 that is able to be connected to the tripping circuit in parallel with the tripping coil 5 by way of a switch 29.

[0050] If the capacitor 27 is connected in parallel with the tripping coil 5, an electric current that charges the capacitor 27 flows into the capacitor 27 in a time interval immediately after the tripping circuit has been closed. As a result, the current flowing in the tripping coil 5 is reduced in comparison with the case in which the capacitor 27 is not connected into the tripping circuit, and therefore the tripping time of the tripping device 1 is conversely increased. When the capacitor 27 is charged, the DC resistance of the capacitor 27 is practically infinite and the current in the tripping circuit flows practically exclusively in the current path with the tripping coil 5, with the result that the tripping coil 5 generates the same magnetic field and therefore effects the same force on the tripping element 3 as in the case in which the capacitor 27 is not connected into the tripping circuit. Therefore, connecting in the capacitor 27 increases the tripping time of the tripping device 1, but hardly changes the force on the tripping element 3 caused by the magnetic field generated by the tripping coil 5 in comparison with the case in which the capacitor 27 is not connected to the tripping circuit.

[0051] FIG. 7 (FIG. 7) shows a schematic illustration of a fifth exemplary embodiment of a tripping device 1, according to the invention, for a circuit breaker. This exemplary embodiment only differs from the exemplary embodiment shown in FIGS. and 6 in that the capacitor 27 has a settable capacitance. The capacitive resistance of the capacitor 27, and therefore the increase in the tripping time of the tripping device 1, are settable in comparison with the case in which the capacitor 27 is not connected to the tripping circuit, due to the ability of the capacitance of the capacitor 27 to be set.

[0052] FIG. 8 (FIG. 8) shows a circuit diagram of a sixth exemplary embodiment of a tripping device 1, according to the invention, for a circuit breaker. This exemplary embodiment only differs from the exemplary embodiment shown in FIGS. 5 and 6 in that, instead of just the capacitor 27, a series connection of a capacitor 27 and an electrical resistor 31 is able to be connected in parallel with the tripping coil 5 by way of the switch 29. The electrical resistor 31 increases the charging duration for charging the capacitor 27 after the tripping circuit has been closed, and therefore the tripping time of the tripping device 1, in comparison with the case in which just the capacitor 27 is connected in parallel with the tripping coil 5.

[0053] FIG. 9 (FIG. 9) shows a circuit diagram of a seventh exemplary embodiment of a tripping device 1, according to the invention, for a circuit breaker. This exemplary embodiment only differs from the exemplary embodiment shown in FIG. 8 in that the electrical resistor 31 has a settable ohmic resistance. The charging time for charging the capacitor 27 after the tripping circuit has been closed, and therefore the increase in the tripping time of the tripping device 1, are settable in comparison with the case in which the capacitor 27 and the electrical resistor 31 are not connected to the tripping circuit, due to the ability of the ohmic resistance of the electrical resistor 31 to be set.

[0054] FIG. 10 (FIG. 10) shows a circuit diagram of an eighth exemplary embodiment of a tripping device 1, according to the invention, for a circuit breaker. This exemplary embodiment only differs from the exemplary embodiment shown in FIGS. 1 and 2 in that a settable electrical resistor 31 is connected in series with the tripping coil 5.

[0055] The exemplary embodiments, shown in FIGS. 1 to 10, of a tripping device 1 according to the invention can be modified in various ways to form further exemplary embodiments. By way of example, the delay coil 9 and the second magnetic core 15 can be arranged outside of the housing 17 instead of inside of the housing 17 as in FIGS. 1 to 4. Accordingly, the capacitor 27, or the capacitor 27 and the electrical resistor 31, can be arranged outside of the housing 17 instead of inside of the housing 17 as in FIGS. 5 to 9. Furthermore, the second magnetic core 15 can be omitted in the exemplary embodiments shown in FIGS. 1 and 4 if the delay coil 9 has a sufficiently high inductance even without the second magnetic core 15. By way of example, the exemplary embodiment shown in FIG. 4 can also be modified in such a way that the delay coil 9 has an adjustable tap instead of a plurality of discrete taps 23 to 26. Moreover, the exemplary embodiments shown in FIGS. 3 and 4 can be combined with one another by virtue of both the second magnetic core 15 being configured so as to be displaceable and the number of turns of the delay coil 9, through which turns current flows, being configured so as to be settable. Analogously, the exemplary embodiments shown in FIGS. 7 and 8 or 9 can be combined with one another by virtue of the capacitor 27 having a settable capacitance and an electrical resistor 31, in particular having a settable ohmic resistance, additionally being able to be connected to the tripping circuit. Furthermore, analogously to the exemplary embodiment shown in FIG. 10, the exemplary embodiments shown in FIGS. 3 and 4 can be extended by an electrical resistor 31 that is connected in series with the delay coil 9. In addition, an exemplary embodiment shown in FIG. 1 to 4 or 10 can be combined with an exemplary embodiment shown in FIGS. 5 to 9 to form an exemplary embodiment that has both a delay coil 9 and a capacitor 27.

[0056] Although the invention has been described and illustrated more specifically in detail by means of preferred exemplary embodiments, the invention is not restricted by the disclosed examples and other variations can be derived therefrom by a person skilled in the art without departing from the scope of protection of the invention.