Electrical switching device with auxiliary contacts

Abstract

An electrical disconnect device comprises a fuse (14) for disconnecting a power line in which direct current circulates, a movable drawer (16; 16A, 16B) connected to the fuse and capable of moving in a fixed cavity (22; 22A) under the action of a compression spring (28) installed between the fixed cavity and the movable drawer once the fuse is disconnected, and an auxiliary contact, wherein a fixed contact part (320A, 320B) of the auxiliary contact is fixed to the fixed cavity, and a movable contact part (322A, 322B) is fixed to the movable drawer, and movement of the movable contact part will cause the normally closed auxiliary contact to disconnect.

Description

Technical Field

[0001] The present invention relates to the general field of electrical disconnect devices for direct current, preferably high voltage direct current (HVDC), power supply networks and more particularly aircraft propulsion systems. Prior art

[0002] An electrical disconnection system known by the term "high temperature fuse" or "high temperature switch" is an assembly consisting of a pyrotechnic actuator and a fuse triggered by the actuator. It is used to disconnect a power line in which a direct current circulates in the event of a short circuit or excessive current. The pyrotechnic actuator then helps the fuse to disconnect the power line under extreme conditions, through the combined action of the melting of the fuse element and the mechanical action of stretching the fuse, which helps to disconnect the fuse. There are also electrical disconnection systems with mechanical actuators or other systems without any actuator.

[0003] However, if such devices are generally satisfactory, it is difficult to ensure the blowing of fuses or proper triggering of actuators (when they exist), and during the disconnection of the power line, devices that cannot operate without fuses in good operating condition may suffer dormant faults. Summary of the invention

[0004] Therefore, the main object of the present invention is to ensure that the state of the fuse is continuously monitored throughout its life and regardless of its activation mode. Another object is also to ensure that the auxiliary contact detecting the state has reached its limit.

[0005] These objects are achieved by an electrical disconnect device comprising a fuse for disconnecting a power line in which a direct current circulates, characterized in that it further comprises a movable drawer connected to the fuse and capable of moving in a fixed cavity under the action of a compression spring mounted between the fixed cavity and the movable drawer once the fuse is disconnected, and an auxiliary contact, the fixed contact part of the auxiliary contact being fixed to the fixed cavity, and a movable contact part being fixed to the movable drawer, the movement of which will cause the normally closed auxiliary contact to be disconnected.

[0006] Advantageously, the auxiliary contacts are galvanically isolated from the power supply line.

[0007] The addition of an auxiliary open circuit detection circuit with galvanic isolation from the power circuit ensures the ability to monitor the fuse status regardless of its activation mode, short circuit, pyrotechnic or mechanical activation.

[0008] Preferably, the movable drawer is fixed to one end of the fuse by a first fixing screw.

[0009] Advantageously, the movable drawer is composed of a sliding member sliding in the fixing cavity and a stopper abutting against the fixing cavity and fixed to the sliding member by a second fixing screw.

[0010] Preferably, the fixed contact part and the movable contact part of the auxiliary contact are each composed of a copper strip and a silver pad.

[0011] Advantageously, the movable contact member is mounted on a partition plate fixed to the stopper by a third fixing screw.

[0012] Preferably, auxiliary contacts are connected to the Sub-D connector in order to enable external signal processing.

[0013] According to one embodiment, the disconnect device comprises a limit switch contact having a copper strip and a silver pad.

[0014] Preferably, the fuse is triggered by a pyrotechnic or mechanical actuator.

[0015] The invention also relates to a high voltage direct current (HVDC) power supply network comprising a disconnection device as described above, and to an aircraft propulsion system comprising such a high voltage direct current power supply network.

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features and advantages of the present invention will become apparent from the following description given with reference to the accompanying drawings, which show an exemplary embodiment without any limitation, in which:

[0018] Figure 1 is a cross-sectional view of a cutting device according to the present invention in a passive position,

[0019] Figure 2 is a cross-sectional view of a cutting device according to the invention in an active position, and

[0020] Figure 3 yes Figure 1 and 2 External perspective view of the disconnecting device at the level of its auxiliary contacts. DETAILED DESCRIPTION

[0021] The principle of the invention is based on the fact that as soon as an overcurrent passes through a fuse of the electrical disconnecting device and causes it to melt, the drawer provided with the auxiliary contacts is no longer held by this fuse and then moves into the chamber under the action of a pressurized compression spring and then returns to its free position, releasing the auxiliary contacts and thus signaling the opening of the fuse, thus ensuring the monitoring of said fuse.

[0022] As an example, Figure 1 and 2An electrical disconnect device 10 is shown in two different positions and comprises a pyrotechnic or mechanical actuator 12 and a fuse 14 triggered by the actuator and serving to disconnect a power line in which a high voltage direct current circulates. The pyrotechnic or mechanical actuator, known per se, will not be described in detail.

[0023] exist Figure 1 In the first position of the disconnecting device, the disconnecting device is stationary, the fuse 14 of the device is in perfect condition and extends between a first fixed end 14A and a second movable end 14B, which is fixed to the movable drawer 16 by a first fixing screw 18. The drawer can be moved in translation in a housing 20 mounted in a fixed chamber 22 in the body 10A of the disconnecting device. The movable drawer is advantageously made of two parts, a slide 16A and a stop 16B. The slide 16A is mounted in translation in the housing 20 and is in the form of a shaft with a shoulder, the shoulder 160 being permanently positioned in the housing 20. The slide 16A has a first end fixed to the fuse 14 via a first fixing screw 18 and a second end fixed in a blind hole 24 of the stop 16B via a second fixing screw 26. The stopper 16B, fixed to the slide 16A by a second fixing screw 26 , places the compression spring 28 , which then has a length Lp in place, under pressure until it is pressed against the fixing cavity 22 via a connecting ring 30 mounted in the housing 20 and having a thickness corresponding to that of the shoulder 160 .

[0024] An auxiliary contact 32 is provided, whose fixed contact part 32A is fixed to the fixed cavity 22 (more specifically, fixed to the Figure 3 The offset part 22A of the fixed cavity visible therein and the movable contact part 32B facing it are fixed to the movable drawer 16 (more precisely, directly to the stopper 16B, or via a partition plate 34 ( Figure 3 It can be seen that, depending on the material properties of the stopper, it is used to ensure the function of detecting the tearing (melting) of the fuse, and the movement of the fuse via the slider 16A and the compression spring 28 will cause the normally closed auxiliary contact (NC) to be disconnected in the static position of the disconnection device. Each fixed or movable contact part is composed of a copper strip 320A, 320B and a silver pad 322A, 322B, and the contact of the two silver pads indicates the closure of the auxiliary contact. It should be noted that since there is no conductive connection between the auxiliary contact and the power line, a galvanic isolation is formed between the two.

[0025] The two copper strips of the two fixed and movable contact parts are connected by wiring to a Sub-D type connector (not shown) which can read the state of the auxiliary contacts and thus monitor and know the state of the fuse of the electrical disconnect device.

[0026] exist Figure 2In the second position, the fuse 14 has been blown by heat or disconnected due to any other undesirable reason, so the slider 16A sliding in the fixed cavity 22 is translated under the action of the compression spring 28, and the compression spring 28 then returns to its free length L0.

[0027] In fact, when the disconnecting device 10 moves from its rest (and therefore passive) position to the active operating position, the slider 16A fixed to one end of the fuse 14 can be driven in translation under the action of the release of the compression spring, so that its shoulder 160 abuts against the connecting ring 30 held against the fixed cavity 22 by the compression spring 28. The bearing surface 162 of the stopper 16B is now separated from the fixed cavity, against which it once abutted via the connecting ring 30, and this separation activates the normally closed auxiliary contact 32 (set in motion). The movable contact part 32B fixed to the stopper 16B is then activated and separated from the opposite fixed contact part 32A fixed to the fixed cavity 5, the auxiliary contact then being in the open position.

[0028] It will be noted that when the normally closed auxiliary contact is coupled to a normally open auxiliary contact consisting of another copper strip 380 and a silver pad 382, ​​as shown, it is possible to ensure that the system reaches its limit under the action of the compression spring 28.

Claims

1. An electrical disconnect device comprising a fuse for disconnecting a power line in which direct current circulates, characterized in that It also includes a movable drawer connected to the fuse, once the fuse is disconnected, the movable drawer can move in a fixed cavity under the action of a compression spring installed between the fixed cavity and the movable drawer, and an auxiliary contact, the fixed contact part of the auxiliary contact is fixed to the fixed cavity, and the movable contact part is fixed to the movable drawer, and the movement of the movable contact part will cause the normally closed auxiliary contact to be disconnected.

2. The cutting device according to claim 1, wherein: The auxiliary contacts are electrically isolated from the power line.

3. The cutting device according to claim 1, wherein: The movable drawer is fixed to one end of the fuse by a first fixing screw.

4. The cutting device according to claim 1, wherein: The movable drawer is composed of a sliding member sliding in the fixing cavity and a stopper abutting against the fixing cavity and fixed to the sliding member by a second fixing screw.

5. The cutting device according to claim 1, wherein: The auxiliary contacts are connected to the Sub-D connector to enable external signal processing.

6. The cutting device according to claim 4, wherein: The fixed contact part and the movable contact part of the auxiliary contact are respectively composed of a copper strip and a silver pad.

7. The cutting device according to claim 6, wherein: The movable contact member is mounted on a partition plate fixed to the stopper by a third fixing screw.

8. The disconnect device of claim 1, further comprising a limit switch contact having a copper strip and a silver pad.

9. The cutting device according to claim 1, wherein: The fuse is triggered by a pyrotechnic or mechanical actuator.

10. A high voltage direct current (HVDC) power supply network comprising a disconnection device according to claim 9.

11. An aircraft propulsion system comprising the high voltage direct current power supply network according to claim 10.

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