GB2511388A - A trip device for a contactor - Google Patents

Abstract

A trip device for a contactor in the form of an electrical vacuum switch 6 having at least two contacts 7, 8 that can be displaced relative to each other for achieving a current flow comprises an axial component 13 under spring pressure 12 to actuate at least one contact; an interlock that retains the axial component 13 out of engagement in opposition to the spring 12; and a drive 21 to release the interlock. A contact ring (fig 4, 11) connected to the head of axial component 13can be axially displaceable in a housing plate 19 and have electrical connection with moving contact 8 via a spring (fig 5, 20). Tripping device 2 and vacuum switch 6 may be housed in a common housing 1. The interlock can comprise a lever 23 that engages another lever 26 supported in housing 1 and connected to a handle 32 outside the housing, by which the trip device may be reset. Interlock release drive 21 may comprise an electromagnetic, hydraulic or mechanical drive. There may be position sensor (fig 6, 35) indicating whether the switch is held open by the interlock, or tripped.

Description

A trip device for a contactor The invention relates to a trip device for a contactor in the form of an electrical vacuum switch having at least two contacts that can be displaced relative to eaoh other in order to achieve current flow.

A vacuum switch is known from EF 0 045 072 Bl, wherein two contacts protrude into an arcing chamber. The contacts are connected to electrical terminals by means of flexible conductors outside of the arcing charter. One electrical contact is fixed relative to the arcing chamber. The other corresponding contact is pivotally joined by means of an actuation mechanism. The other contact can be displaced between an open position and a closed position by means of the displacement mechanism.

DE 40 05 532 Al discloses a vacuum switch having a vacuum arcing chanber. In order to mount the vacuum arcing chamber, a compliant connection connects the vacuum arcing chamber to an external terminal. The vacuum arcing chamber is in addition connected to the switch construction by means of an axial traction mechanism.

A disadvantage of known vacuum switches is that clearances arise during operation of the switch dile to friction occurring in the linkage elements communicating with each other. Such clearance has a negative effect on parameters such as the opening width and the simultaneously operation of the contacts. The function of the vacuum switch is thereby significantly negatively affected. Another disadvantage of vacuum switches known from the state of the art is the sometimes complex technical construction thereof.

The aim of the invention is therefore to provide a trip device for a contactor having a significantly reduced tripping time.

The device should operate with high reliability and should be produced at an economical price.

The aim is addressed by the features set out in the characterising part of claim 1.

The contactor is a switch that protects electrical lines and devices (such as motors) from overcurrents and excessively low voltages by switching off.

The present specification defines a vacuum switch as a construction of a heavy-duty switch in electrical power engineering. The contacts of such a vacuum switch are disposed in an air-free space (vacuum) in order to reduce undesired switching arcs.

The present invention relates to a trip device for a contactor, wherein the contactor is in the form of an electrical vacuum switch having at least two contacts. The contacts are displaceable relative to each other in order to achieve a current flow. One contact of the vacuum switch may be attached to the switch housing, for example. The other contact of the vacuum switch is indirectly connected to an axial component by means of a contact ring. The axial component, under pressure from a compression spring, actuates at least one of the at least two contacts.

According to the present invention, an interlock holds the axial component out of engagement against the spring pressure, wherein a drive is provided for releasing the interlock. As the compression spring expands, the compression spring transmits the kinetic energy stored in the compressed compression springs to the axial component. The vacuum contactor can be used as a circuit breaker for nearly all high-voltage ranges. The vacuum contactor thereby makes use of the exceptionally high electric strength of the vacuum. The low number of gas molecules available for ionizations makes it possible to eliminate the switching arc that would otherwise occur, even for very short switching element distances. In this manner, very high voltages can be handled without sparkover occurring.

Another preferred embodiment of the invention provides that a contact ring actuating the contacts and axially displaceably guided in a housing plate is disposed at the head of the axial component.

The contact ring may be connected to the at least one contact of the vacuum contactor on the side thereof facing away from the axial component.

Contact springs responsible for maintaining the current-bearing contact between the housing plate and the contact ring may be provided in an opening of the housing plate. The contact springs may be disposed at the inner circumference of the opening in the housing plate and aligned toward the center of the opening. The contact springs ensure that an uninterrupted current flow remains intact between the housing plate and the contact ring, even during axial guiding of the contact ring in the housing plate.

A further preferred embodiment of the invention provides that the interlock may be made of a lever works supported in a housing, one lever thereof engaging on the drive and another lever straining the compression spring. Both levers comprise an arm engaging with the corresponding other lever.

Depending on the size and scope of the contactor, the compression spring and the lever can be implemented in different strengths and shapes. It is also thereby possible to adapt the lever works to the size of the compression spring, so that the compression spring remains compressed in the rest state of the trip device. The lever engaging with the drive may be implemented as a closure lever, and may be pivotally joined to a component of the trip device. The other lever of the lever works may have the form of a support lever. The closure lever comprises at least one receiving notch in which the support lever engages when the compression spring is compressed in the rest state.

The closure lever and the support lever may be each implemented as a double-ended lever. In the rest state in which the compression spring is compressed the support lever latches in the closure lever. The support lever may be pivotally disposed on a U-profile, forming an inner chamber together with an opposing U-profile.

In addition, a preferred variant of the invention provides that the trip device comprises a pneumatic and/or hydraulic and/or mechanical drive. Depending on the field of application of the trip device, an electromagnetic drive can also be used.

The trip device thereby comprises lines that provide the compressed air or the hydraulic oil. For the electromagnetic drive, a solenoid is provided, in which a magnetic field is formed when current flows through.

The drive preferably comprises an extendable piston engaging with the arm of the closure lever.

The piston may be tripped in that a remote controlled contact is closed at the pneumatic, hydraulic, or electromagnetic drive. The contact causes the extendable piston to be displaced out of the housing of the drive. The piston acts on the arm of the closure lever, so that the closure lever is pivoted about the center of gravity thereof and releases the support lever.

In another preferred embodiment, the contactor and the interlock device may be disposed in a common housing. The interior of the common housing is thereby divided into a mechanical chamber and an electrical chamber. Both chambers are separated from each other by a wall.

A handle for actuating the interlock may be disposed on the outside of the housing. The handle can be implemented as an access panel. The access panel may be pivotally mounted on the outer perimeter of the common housing. In the rest state of the trip device, the access panel contacts the outer perimeter of the common housing. The access panel contacting the common housing covers an opening penetrating the side wall of the common housing. When the compression spring expands, the support lever completes a pivot motion in the direction toward the opening covered by access panel.

Tf the vacuum switch is closed, the upper end of the support lever protrudes through the opening of the common housing. In this manner, the access panel is pivoted about the mounting point thereof on the outer perimeter of the common housing, into a position in which the access panel extends at an angle to the outer wall of the housing.

The access panel can be pressed against the support lever from the outside, and pivoted into a position in which the access panel contacts the outer wall of the housing. The access panel thereby acts in such a manner on the support lever that said lever is pivoted in the direction toward the axial component.

In this manner, the support lever may be brought into a position in which said lever engages in the receiving notch of the closure lever.

In another embodiment of the invention, a panel may be disposed or± the switch housing in the area of the upper end of the support lever. The panel may be pivotally joined to the housing and allows access to the support lever.

The closure lever preferably comprises at least one receiving notch.

Tn another advantageous embodiment of the invention, the support lever comprises at least one hook. The hook serves to latch the support lever on the closure lever.

The support lever is preferably pivotable into a closed position and into an open position. The support lever may be indirectly connected to the compression spring by means of the transverse shaft. Depending on the expansion or contraction of the compression spring, the support lever may be pivoted into a closed position or into an open position.

It can also be provided that the U-profiles comprise pivot points. The pivot points serve for pivoting the closure lever and the support lever relative to the U-profile.

An example of a trip device which embodies the present invention is described in further detail below, by way of example and without limiting the generality thereof, using an embodiment example shown in the drawings, in which: Figure 1 shows a side view of a trip device in accordance with the present invention with the support lever in the open position, Figure 2 shows a side section view of the trip device shown in Figure 1, with the support lever in the closed position, Figure 3 shows an exploded view of the trip device shown in Figures 1 and 2, Figure 4 shows a contact ring guided in a housing plate of the device shown in Figures 1 to 3, Figure 5 shows the housing plate shown in Figures 1 to 4 with contact springs, and -10 -Figure 6 is a schematic view of the trip device.

Figure 1 shows a switch housing 1 of the electrical switch according to the invention. The electrical switch comprises an electrical chamber 3 and a mechanical chamber 4. The two chambers 3; 4 are separated from each other by a wall 5.

A vacuum switch 6 is disposed in the electrical chamber 3 and comprises two switch contacts 7 and 8. The two switch contacts 7 and 8 are disposed in the switch housing 1 of the vacuum switch 6. The upper switch contact 7 of the vacuum switch 6 is connected to an electrically conductive circuit board 10. At the lower end thereof, adjacent to the mechanical chamber 4, the switch contact 8 is mounted on a contact ring 11.

A compression spring 12 is shown in the mechanical chamber 4.

An axial component 13 is disposed axially within the coils of the compression spring 12. The reference numeral 14 shows a transverse shaft penetrating the axial component 13. The axial component 13 is supported on the compression spring 12 by means of the transverse shaft thereof.

An inner chamber 16 is disposed in the interior of the mechanical chamber 4, comprising a first and a second U-profile 17; 18. The U-profiles 17; 18 engage in each other and -11 -are connected to each other at the legs thereof. The axial component 13 penetrates the two U-profiles 17; 18 in the area of the upper and lower legs thereof contacting each other. The foot of the axial component 13 is anchored in the legs of the U-profile 17; 18, which are spaced apart from the contact ring 11. The compression spring 12 enclosing the axial component 13 in the coils thereof acts indirectly on contours 34 of the support lever 26 by means of the transverse shaft 14 (Figure 1).

The axial component 13 extends axially within the mechanical chamber 4 of the switch housing 1 and penetrates the wall 5 separating the two chambers 3 and 4 from each other. The axial component 13 penetrates the contact ring 11 within the electrical chamber 3. The contact ring 11 is thereby attached to the axial component 13. The contact ring 11 is guided in a housing plate 19. Contact springs 20 are disposed on the inner perimeter of the housing plate 19, as shown in Figure 4.

The contact ring 11 is axially and/or radially displaceable within the housing plate 19 while maintaining the electrical contact. The contact springs 20 serve for maintaining the electrical contact between the contact ring 11 and the housing plate 19, both during axial and during radial displacement of the contact ring 11 within the housing plate 19.

-12 -The contact ring 11 is attached to the axial component 13 on one side, and to the switch contact 8 of the vacuum switch 6 on the other side. An axial displacement of the axial component 13 in and opposite to the direction of displacement of the compression spring 12 within the switch housing 1 causes an axial displacement of the contact ring 11 within the housing plate 19.

The distance of the switch contact 8 of the vacuum switch 6 from the switch contact 7 of the vacuum switch 6 is changed by the axial displacement of the axial component 13 within the switch housing 1. It is thereby possible to reduce or increase the distance of the switch contact 7 from the switch contact 8.

A drive 21 acting on a long leg 22 of the closure lever 23 by means of a piston 40 is provided in the mechanical chamber 4.

The closure lever 23 is pivotally supported about a pivot point 24 on the U-profile 18. The piston 40 of the drive 21 can actuated by remote control or by any other means. By actuating the piston 40, the closure lever 23 is pivoted about the pivot point 24. The long leg 22 of the closure lever 23 thereby pivots in the direction toward the mechanical chamber 4. The short leg 25 of the closure lever 23 is pivoted -13 -downward, oppositely, in the direction toward the compression spring 12.

By pivoting the closure lever 23 about the pivot point 24, the short leg 25 of the closure lever 23 releases a support lever 26. The support lever 26 is pivotally joined about a pivot point 27 on the U-profile 18. The support lever 26 comprises hooks 28 on the end of the support lever 26 away from the pivot point 27. The hooks 28 of the support lever 26 are provided for engaging in the receiving notches 29 of the closure lever 23 in the closed position of the support lever 26. The closed position of the support lever 26 is shown in Figure 2. In Figure 1, the support lever 26 is in the open position 31.

The upper end of the support lever 26 having the hooks 28 protrudes through an opening 33 of the switch housing 1 in the open position 31. In the open position 31 the support lever 26 presses against a panel 32. The panel 32 is joined to the switch housing 1 by a hinge and the lower end thereof is spaced apart from the switch housing 1 in Figure 1.

Figure 1 shows the compression spring 12 in the relaxed state.

The compression spring 12 presses against the transverse shaft 14 and displaces the axial component 13 in the direction of -14 -the electrical chamber 3. The transverse shaft 14 engages on a contour 34 of the support lever 26, whereby the support lever 26 is pivoted about the pivot point 27 in the direction toward the opening 33.

Reference numeral 35 shows a position sensor providing information about the current position of the axial component 13.

Figure 2 shows an electrical switch corresponding to that of Figure 1, with the difference that the switch is shown in a section view longitudinal to the closure lever 23. The support lever 26 is pivoted about the pivot point 27 back into the closed position 30, and extends approximately parallel to the axial component 13. The contour 34 of the support lever 26 presses the compression spring 12 indirectly against the leg of the U-profiles 17; 18 by means of the transverse shaft. The hooks 28 of the support lever 26 engage in the receiving notches 29 of the closure lever 23 in the closed position 30 of the support lever 26. The drive 21 is not activated, and the closure lever 23 extends approximately horizontally relative to the pivot point 24. The closure lever 23 is retained in an approximately horizontal position by the piston of the drive 21 in the closed position 30 of the support lever 26. The closure lever 23 thereby secures the support -15 -lever 26 against pivoting about the pivot point 27, counteracting the expansion force of the compression spring 12.

Because the support lever 26 is in the closed position 30, the panel 32 is olosed and contaots the switoh housing at the hinge point thereof. Figure 2 shows screws 36 by means of which the corresponding upper switch contact 7 of the vacuum switch 6 is attached to the electrically conductive circuit board 10. A further screw 36 connects the switch contact 8 of the vacuum switch 6 to the contact ring 11.

Reference numeral 1 indicates the switch housing in Figure 3.

Tn the installed state, the switch housing 1 is closed by means of a cover 37. The axial component 13 is disposed above the compression spring 12 and comprises the transverse shaft 14 running transverse to the axial component 13. The position sensor 35 is mounted below the transverse shaft 14. A retaining ring is provided for mounting the axial component 13 relative to the legs of the U-profiles 17; 18. At the end of the axial component 13 opposite the compression spring 12, a contact surface can be seen, with which the contact ring makes contact in the installed state.

-16 -The housing plate 19 is shown above the contact ring 11 relative to the axial component 13 and comprises an opening 33 having contact springs 20 aligned toward the opening side. The vacuum switch 6 is shown between the housing plate 19 and the circuit board 10. The vacuum switch 6 comprises the upper switch contact 7 and the lower switch contact 8 on the axial component side. When the switch contacts 7; 8 of the vacuum switch 6 are connected by closing the trip device according to the invention, the electrical circuit is closed in order to implement the function of the switch as a bypass switch. The U-profiles 17; 18 are shown on both sides of the axial component 13, forming the inner chamber 16.

To this end, the legs of the U-profiles 17; 18 engage with each other in a form-fit manner. The closure lever 23 is shown on one side of the axial component 13 and is pivotally joined about the pivot point 24 of the U-profile 18 in the installed state. The receiving notches 29 are disposed on the short legs of the closure lever 23. The support lever 26 is shown on the opposite side of the axial component 13 and is pivotally joined about the pivot point 27 of the U-profile 18 in the installed state.

Figure 3 shows the arrangement of the pivot points 24 and 27 at different heights on the side of the U-profile 18. The -17 -support lever 26 is shown behind the U-profile 18 relative to the axial component 13. The support lever 26 comprises the hooks 28 at the upper end thereof, said hooks being provided for actively connecting to the receiving notches 29 of the closure lever 23. The panel 32 is disposed behind the support lever 26 relative to the axial component 13, said panel being joined with a hinge at the side of the switch housing 1 in the installed state.

The inner chamber 16 of the drive 21 extends approximately parallel to the axial component 13 within the U-profiles 17; 18. The drive 21 is actively connected to the closure lever 23 by means of a piston 40.

Guides 38 for the circuit board 10, the housing plate 19, and the axial component 13 can be seen in the interior of the switch housing. In order to mount the switch housing 1 on a support structure, a mounting rail 39 is provided on the front face of the switch housing 1.

The contact ring 11 and the housing plate 19 are connected to each other in Figure 4 by means of the contact springs 20.

When the contact ring 11 is axially displaced within the housing plate 19, a current flow between the housing plate 19 and the contact ring 11 remains intact in this manner. The -18 -contact ring II comprises holes 42; 43. The hole 42 is for the screw connection of the contact ring 11 to the switch contact 7 and the hole 43 is for the screw connection of the contact ring 11 to the axial component 13.

The housing plate 19 is shown in a perspective view in Figure 5. The contact ring II attached to the axial component 13 is guided in the opening 33 of the housing plate 19 in the installed state. In case of axial and/or radial displacement of the contact ring 11 within the housing plate 19, the current-carrying contact between the contact ring 11 and the housing plate 19 remains intact. The current-carrying contact is ensured by the contact of contact ring 11 with The contact springs 20 of the housing plate 19.

A position sensor is provided, which is shown in the schematic view of Figure 6 and indicated by reference numeral 35. If the interlock of the trip device for the contactor is in the rest state, the compression spring 12 holds the axial component 13 out of engagement against the spring pressure. For releasing the interlock, a drive 21 is provided, which is illustrated in the form of a magnet. In addition, a position sensor 35 provides information on whether the trip device for the contactor is interlocked or whether the interlock of the trip device is released.

-19 -The position sensor 35 has two switch positions. Normally, the trip device for the contactor is not actuated, and the switch contacts 7 and 8 of the vacuum switch 6 are interrupted.

In this position, the switch contact 49 of the position sensor is open, whereas the switch contact 50 of the position sensor 35 is closed. A circuit 46 between a driver 47 and an element 48 is closed.

Once the trip device is activated by the drive 21, the switch contact 50 is opened. The switch contact 49 is closed simultaneously and voltage thereby applied to the circuit 51.

A magnet 54 of a further drive 52 is disposed in the circuit 51. If the circuit 51 is closed, voltage is applied to the magnet 54 of the further drive 52.

Figure 6 shows the position sensor 35 configured in the form of a micro switch with a magnet 54 of a mechanical interrupter device 53. The mechanical interrupter device 53 is only shown schematically.

The magnet 54 trips the mechanical interruption device 53, which in turn generates a signal that the trip device for the contactor is activated by releasing the interlock of the drive 21. The interrupter device 53 simultaneously disconnects the -20 -power supply of the magnet 54 of the further drive 52 by interrupting the circuit 51.

In Figure 6, a safety switch (snap switch) 55 is further provided, maintaining continuous voltage in the circuit 46.

The driver 47 is connected to a low-side driver 55 via the safety switch 55.

-21 -Reference numerals 1 Switch housing 3 Electrical chamber 4 Mechanical chamber Wall 6 Vacuum switch 7; 8 switch contact Circuit board 11 Contact ring 12 Compression spring 13 Axial component 14 Transverse shaft 16 Tnner chamber 17, 18 U-Profile 19 Housing plate Contact spring 21 Drive 22 Long leg 23 Closure lever 24 Closure lever pivot point Short leg 26 Support lever 27 Pivot point 28 Hook -22 - 29 Receiving notch closed position 31 Open position 32 Panel 33 Opening 34 contour Position sensor 36 Screws 37 cover 38 Guide 39 Mcunting rail Piston 42; 43 Hole 46 circuit 47 Driver 48 Element 49 Switch contact 51 circuit 52 Drive Interrupter device 54 Magnet