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EP-4738407-A1 - ELECTRIC SWITCH

EP4738407A1EP 4738407 A1EP4738407 A1EP 4738407A1EP-4738407-A1

Abstract

An electric switch comprising a frame (2), a first stationary contact (41), a roll element (6) adapted to rotate relative to the frame (2), a rotating contact (8) stationarily fixed to the roll element (6), and an arc shutter system adapted to enhance extinguishing of an electric arc between the first stationary contact (41) and the rotating contact (8) during an opening event of the electric switch. The arc shutter system comprises a first arc shutter (91) movable relative to the frame (2) between a first position and second position, and a counterpart member (92) adapted to cooperate with the first arc shutter (91) in order to enhance extinguishing of the electric arc by squeezing the electric arc between the first arc shutter (91) and the counterpart member (92).

Inventors

  • Mäki, Markus
  • LEHTIMÄKI, Jarmo
  • UUSITALO, KAI

Assignees

  • ABB SCHWEIZ AG

Dates

Publication Date
20260506
Application Date
20241030

Claims (14)

  1. An electric switch comprising: a frame (2); a first stationary contact (41) stationarily fixed to the frame (2), and adapted to be connected to a power supply; a roll element (6) rotatable relative to the frame (2) around a rotation axis (16) between a first position and a second position; a rotating contact (8) stationarily fixed to the roll element (6), and comprising a first contact portion (81) such that in the first position of the roll element (6) the first contact portion (81) is electrically conductively connected to the first stationary contact (41), and in the second position of the roll element (6) the rotating contact (8) is disconnected from the first stationary contact (41), an arc shutter system adapted to enhance extinguishing of an electric arc between the first stationary contact (41) and the first contact portion (81) of the rotating contact (8) during an opening event of the electric switch, wherein the arc shutter system comprises a first arc shutter (91) movable relative to the frame (2) between a first position and second position, characterized in that the arc shutter system comprises a counterpart member (92) adapted to cooperate with the first arc shutter (91) in order to enhance extinguishing of the electric arc by squeezing the electric arc between the first arc shutter (91) and the counterpart member (92).
  2. The electric switch as claimed in claim 1, wherein at the final stage of the movement of the first arc shutter (91) from the first position to the second position, the first arc shutter (91) moves towards the counterpart member (92).
  3. The electric switch as claimed in claim 1 or 2, wherein in the second position of the first arc shutter (91), a distance between the first arc shutter (91) and the counterpart member (92) is less than or equal to 1.5 mm.
  4. The electric switch as claimed in claim 1 or 2, wherein in the second position of the first arc shutter (91), the first arc shutter (91) is in contact with the counterpart member (92) such that a route of the electric arc is closed.
  5. The electric switch as claimed in claim 4, wherein a contact surface of the first arc shutter (91) and/or a contact surface of the counterpart member (92) is made of elastic material, wherein said contact surfaces are surfaces that are adapted to be in contact with each other in the second position of the first arc shutter (91).
  6. The electric switch as claimed in any one of the preceding claims, wherein the first arc shutter (91) is rotatable relative to the frame (2) around a shutter axis between the first position and second position.
  7. The electric switch as claimed in claim 6, wherein the shutter axis is spaced apart from the rotation axis (16) such that in a longitudinal direction perpendicular to the rotation axis (16), an arc section (417) of the first stationary contact (41) is located between the rotation axis (16) and the shutter axis, wherein the arc section (417) is a section of the first stationary contact (41) on which an end of the electric arc is located during the opening event.
  8. The electric switch as claimed in claim 6 or 7, wherein a rotational angle between the first position and second position of the first arc shutter (91) is greater than a rotational angle between the first position and second position of the roll element (6).
  9. The electric switch as claimed in any one of the preceding claims, wherein the electric switch comprises a transmission mechanism for transferring power to the arc shutter system from a component of the electric switch adapted to move during the opening event.
  10. The electric switch as claimed in claim 9, wherein the transmission mechanism is adapted for transferring power from the roll element (6) to the first arc shutter (91) such that rotation of the roll element (6) moves the first arc shutter (91) relative to the frame (2).
  11. The electric switch as claimed in claim 10, wherein the transmission mechanism comprises a first cogwheel (11) stationarily connected relative to the roll element (6), and a second cogwheel (12) stationarily connected relative to the first arc shutter (91).
  12. The electric switch as claimed in any one of the preceding claims, wherein a lateral dimension of the first arc shutter (91) is greater than a lateral dimension of the first contact portion (81) and greater than a lateral dimension of an arc section (417) of the first stationary contact (41), wherein the arc section (417) is a section of the first stationary contact (41) on which an end of the electric arc is located during the opening event, and wherein the lateral dimensions are parallel to the rotation axis (16).
  13. The electric switch as claimed in any one of the preceding claims, wherein the first stationary contact (41) and the first contact portion (81) of the rotating contact (8) are adapted to cooperate as knife contacts.
  14. The electric switch as claimed in any one of the preceding claims, wherein a rotational angle of the roll element (6) around the rotation axis (16) is limited to an angle less than or equal to 120°.

Description

FIELD OF THE INVENTION The present invention relates to an electric switch. BACKGROUND OF THE INVENTION An electric switch is a device adapted to open and close an electric circuit it is connected to. When an electric circuit is opened by an electric switch, an electric arc whose temperature is thousands of degrees may occur in the electric switch. An electric arc includes ionized gas, which contains a large number of free electrons. Such a gas plasma is electrically conductive. An electric arc delays transfer of an electric switch from a conducting state to a non-conducting state. Further, an electric arc is often harmful for an electric switch and for an electric assembly comprising the electric switch. It is known in the art to use an arc shutter system to enhance extinguishing of an electric arc during an opening event of an electric switch. Examples of known electric switches provided with arc shutter systems are described in publications EP4376038A1 and EP3985700A1. The arc shutter systems described in said publications are especially efficient in electric switches in which a rotational angle of a rotating contact is relatively large, approximately 90° or larger. BRIEF DESCRIPTION OF THE INVENTION An object of the present invention is to provide an electric switch with an arc shutter system capable of efficiently extinguishing an electric arc even when a rotational angle of a rotating contact is relatively small. The objects of the invention are achieved by an electric switch which is characterized by what is stated in the independent claim. The preferred embodiments of the invention are disclosed in the dependent claims. The invention is based on the idea of providing an arc shutter system which is adapted to enhance extinguishing of the electric arc by squeezing the electric arc between a first arc shutter and a counterpart member. The arc shutter system is adapted to reduce a cross-sectional area of a route of the electric arc such that the electric arc extinguishes. An advantage of the electric switch of the invention is that the arc shutter system thereof is capable of efficiently extinguishing an electric arc even when a rotational angle of a rotating contact is relatively small, for example 45°. BRIEF DESCRIPTION OF THE DRAWINGS In the following the invention will be described in greater detail by means of preferred embodiments with reference to the attached drawings, in which Figures 1 to 3 show a switch assembly comprising an electric switch according to an embodiment of the invention;Figure 4 shows a portion of the switch assembly shown in Figure 3;Figure 5 is a side view of the portion of the switch assembly shown in Figure 4;Figure 6 shows a side view of a mechanism of an electric switch according to another embodiment of the invention;Figure 7 shows a side view of a mechanism of an electric switch according to yet another embodiment of the invention; andFigures 8 and 9 show side views of a mechanism of an electric switch according to yet another embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION Figure 1 shows a switch assembly comprising an electric switch according to an embodiment of the invention, and a control module 101 adapted to control the electric switch. In Figure 1, the switch assembly is partly disassembled in order to show an internal structure of the switch assembly. The electric switch shown in Figure 1 comprises a frame 2, a first stationary contact 41, a second stationary contact 42, a roll element 6, a rotating contact 8, an arc shutter system and a transmission mechanism. The first stationary contact 41 is stationarily fixed to the frame 2 and is adapted to be connected to a power supply. The second stationary contact 42 is stationarily fixed to the frame 2 and is adapted to be connected to a load. The roll element 6 is adapted to rotate relative to the frame 2 around a rotation axis between a first position and second position. A rotational angle of the roll element 6 between the first position and the second position is 45°. In an alternative embodiment, a rotational angle of the roll element around the rotation axis is limited to an angle less than or equal to 70°. In another alternative embodiment, a rotational angle of the roll element around the rotation axis is limited to an angle less than or equal to 120°. The rotating contact 8 is stationarily fixed to the roll element 6, and comprises a first contact portion 81. In Figure 1, the roll element 6 is in the first position thereof, in which the first contact portion 81 is electrically conductively connected to the first stationary contact 41. The first position of the roll element 6 provides an on-position or connected position of the electric switch in which the rotating contact 8 electrically conductively connects the first stationary contact 41 and the second stationary contact 42. The first stationary contact 41 and the first contact portion 81 of the rotating contact 8 are adapted to cooperat