JP7303010B2 - Filter capacitor short-circuit device, short-circuit method - Google Patents

Description

The present invention relates to a filter capacitor short-circuiting device and a short-circuiting method.
For example, in a high-voltage inverter device, the capacitor terminals (positive P terminal, negative N terminal) of a filter capacitor that cannot be removed from the main body of the device during voltage application are connected to the main circuit wiring (P, N terminal) of the high-voltage inverter device. ) and is suitable for safely storing a filter capacitor built in a unit that can be removed from the high-voltage inverter device according to specifications .

2. Description of the Related Art In a high-voltage inverter device that converts DC power into AC power, a filter capacitor is mounted on the DC circuit side as a smoothing circuit. In some high-voltage inverter devices, the filter capacitor can be taken out and replaced for maintenance or the like.
The problem in such cases is electric shock due to the high voltage charged on the filter capacitor.
That is, when the high-voltage inverter device is energized, the filter capacitor is pressurized, and a high voltage is generated between the positive P terminal and the negative N terminal of the filter capacitor. This high voltage causes charge to remain in the filter capacitor even after the supply of electricity is stopped. As a result, a high voltage is left between the P and N terminals as a residual charge, and there is a danger that an operator will receive an electric shock during maintenance.
Therefore, in order to ensure safety, there is a method to naturally discharge the residual charge of the capacitor by using the internal resistance component of the capacitor or a discharge resistor connected in parallel before maintenance work, is forced to discharge by using a mechanism that short-circuits with a conductor connected to a discharge resistor. For example, as a method of forcibly discharging, there is a technique described in Japanese Patent Publication No. 2012-090720 (Patent Document 1).
This publication describes a discharge mechanism for discharging residual electric charge in a high-voltage inverter device, which includes a pair of discharge terminals connected to the positive and negative sides of a capacitor provided in an inverter circuit of the high-voltage inverter device, and a discharge resistor. and short-circuiting means for discharging the residual charge of the capacitor by short-circuiting the pair of discharge terminals in a conductive state."

Japanese Patent Publication No. 2012-090720

When performing maintenance on a high-voltage inverter, for example, a unit without built-in filter capacitor (see unit 108 without built-in filter capacitor in FIG. 9) is replaced with a unit with built-in filter capacitor (see unit 106 with built-in filter capacitor in FIG. 8). sometimes.
In such a case, there is a method of removing the filter capacitor which becomes the surplus capacity. However, there are cases in which it is impossible to remove the filter capacitor from the high-voltage inverter due to the specifications so that the filter capacitor can be returned to the existing system or for structural reasons.
Therefore, it is necessary to leave the filter capacitor, which has a surplus capacity, inside the device and electrically insulate the filter capacitor from the main circuit (main circuit wirings P, N) of the high-voltage inverter device. Also, insulated filter capacitors, like capacitors stored as replacement parts, increase the risk of electric shock due to spontaneous charging. Therefore, it is necessary to short-circuit the P and N terminals.
However, Patent Literature 1 does not consider the problem in the case described above.
Therefore, in Patent Document 1, when the residual charge of the high-voltage inverter device is discharged, a pair of discharge terminals connected to the positive electrode side and the negative electrode side of the capacitor of the cell inverter are short-circuited in a state of continuity with the discharge resistor, and the high-voltage inverter device is discharged. The effect is that the residual charge of the capacitor can be discharged by

Therefore, in the present invention, a technology that can be used properly according to the situation of the high-voltage inverter device, for example, one short-circuiting device can be used as a device having a short-circuiting function and a device having both insulation and short-circuiting functions according to the situation. To provide a technology that enables a high-voltage inverter device to operate normally before and after replacement of a unit with a built-in filter capacitor, thereby avoiding the risk of electric shock to a worker during replacement.

In order to solve the above-mentioned problems, one typical short-circuiting device and short-circuiting method of the present invention is a short-circuiting device that short-circuits between the P and N terminals of a filter capacitor, and is attached to the P and N terminals of the filter capacitor. , a terminal short-circuit holding unit that short-circuits the P and N terminals and holds the P and N terminals, and insulates the main circuit wiring P and/or the main circuit N wiring that are connected to the P and N terminals, It has a wiring insulation holding portion for holding the main circuit P wiring and/or the main circuit N wiring.

1 is a schematic diagram of a high-voltage inverter device according to an embodiment; FIG. FIG. 2 is an external perspective view showing the mounting state of main circuit wiring, filter capacitors, and short-circuiting devices that constitute the main circuit of the high-voltage inverter device according to the present embodiment. FIG. 4 is a diagram for explaining the connection relationship between the short-circuiting device, the filter capacitor, and the main circuit wiring according to the embodiment; 1 is an external perspective view showing a short-circuiting device according to an embodiment; FIG. FIG. 4 is a schematic diagram showing the relationship between a short-circuiting device and a unit that incorporates a filter capacitor and is detachable from the device body according to the specifications of the present embodiment when the unit is removed from the device body; FIG. 10 is a diagram showing the filter circuit in an energized state in which the filter capacitor, which cannot be removed due to specifications, cannot be short-circuited; A filter capacitor circuit diagram showing a state in which a filter capacitor that cannot be removed due to specifications is insulated and short-circuited. The figure which shows a filter circuit when using the unit which incorporated the filter capacitor which cannot be removed by specification. The figure which shows the filter circuit using the unit which does not contain a filter capacitor.

The present embodiment will be described below with reference to the drawings.

First, a description will be given on the premise that the short-circuiting device of the present embodiment is applied to a high-voltage inverter device for railway vehicles.
In this case, products mounted on railroad vehicles, including high-voltage inverter devices, are constantly exposed to vibrations. For this reason, high vibration resistance is required. In addition, there is a limitation that a vehicle electronic component such as a capacitor needs to be arranged in an extremely small space, and there is little spatial freedom around it. In addition, since there is a constant demand for reduced mass, a structure that is as light as possible is preferred.

For example, among the high-voltage inverter configuration units for railway vehicles, the power unit, which contains power semiconductor elements, which are core components, has recently been changed from silicon (Si) IGBTs to silicon carbide (SiC) MOSFETs. , a configuration for performing a switching operation at a higher speed can be seen.
When a silicon carbide (SiC) MOSFET is used as a power semiconductor, it is necessary to minimize the inductance between the semiconductor element and the filter capacitor to suppress noise and stabilize the inverter during operation.
For this purpose, a configuration in which the filter capacitor is built in the power unit is desirable. Therefore, for the same high-voltage inverter device, a power unit with a built-in capacitor (see filter capacitor built-in unit 106 in FIG. 8) and a power unit with no built-in capacitor (filter capacitor non-built-in unit 108 in FIG. 9) can be installed. ) are assumed.
Here, for example, when replacing a unit without built-in filter capacitor with a unit with built-in filter capacitor, there is a problem that the total combined capacity of the high-voltage inverter device increases. Therefore, when using a power unit with a built-in filter capacitor, it becomes necessary to insulate the filter capacitor built into the high-voltage inverter device.

In other words, it is only necessary to short-circuit the capacitor inside the high-voltage inverter device when the power unit with built-in filter capacitor is attached to the device main body. As a means for this, for example, as shown in the above-mentioned Patent Document 1, a discharge mechanism having a structure capable of switching between the main circuit insulation/capacitor short-circuited/capacitor energized state is prepared in advance at the filter capacitor terminal portion inside the high-voltage inverter device. and short the capacitor.

That is, in order to switch between the main circuit insulation/capacitor short-circuited state and the capacitor energized state, the short-circuiting conductor that contacts the P and N terminals of the capacitor terminal part is rotated around a rotating shaft with a built-in discharge resistor to cause a short-circuit. This is a method of short-circuiting a capacitor by means of a discharge mechanism having a structure capable of short-circuiting the terminal portions of the P and N terminals of the capacitor via a discharge resistor with a conductor.
However, it is practically difficult to add a discharge mechanism as described in Cited Document 1 to a high-voltage inverter device that has already been delivered to a customer and is in operation at the customer.

In addition, as described above, railroad vehicles are required to be vibration resistant, have limited space, and have a reduced mass. Then, after stopping, the system waits for a specified period of time without touching the device to allow the capacitor to discharge naturally. Therefore, it is not necessary to use a discharge resistor in the circuit that short-circuits the P terminal and the N terminal.
Therefore, the member (short-circuiting member) that short-circuits the P and N terminals of the capacitor may be a general conductor member without any problem. A device having an insulating/short-circuiting function formed in a structure added to the conductor member of (1) can sufficiently perform the required function. In other words, a device having an insulating/short-circuiting function with a simpler structure than the discharge mechanism described in Patent Document 1 is sufficient.

The structure of the device having the insulating/short-circuiting function should be such that it can be easily inserted into the terminal portion of the filter capacitor. As a result, the device having the insulating/short-circuiting function can be easily and simply added to the existing high-voltage inverter device.
That is, by attaching/removing the device having this insulating/short-circuiting function between the filter capacitor and the main circuit wiring, the capacitor can be easily switched from the main circuit to the main circuit isolation/capacitor short-circuit/capacitor energization.

On the other hand, when storing a filter capacitor alone as a replacement part without attaching it to a high-voltage inverter device, if the circuit between the P terminal and the N terminal (capacitor terminal part) is left open, the capacitor will be charged naturally, Electric charge accumulates, and eventually a high voltage is generated between the P and N terminals. For this reason, there is a danger that the operator will receive an electric shock during maintenance. Therefore, in order to ensure safety, conventionally, a method of short-circuiting the P terminal and the N terminal with a conductor such as a wire has been adopted.
In a high-voltage inverter device, by replacing a unit that is detachable according to specifications, it is possible to improve performance while using an existing system. For example, in a power unit with built-in power semiconductor elements, which are core components, switching from silicon (Si) IGBTs to silicon carbide (SiC) MOSFETs will enable faster switching. . At this time, in order to minimize the inductance between the semiconductor element and the filter capacitor, suppress noise during inverter operation, and stabilize the inverter, it is desirable to incorporate the filter capacitor in the power unit.
Similarly, when there is a filter capacitor built in a detachable unit due to specifications, it is necessary to short-circuit the P terminal and the N terminal with a conductor such as a wire during storage.
On the other hand, if the filter capacitor non-incorporated unit is replaced with the filter capacitor incorporated unit, there is a problem that the combined capacity of the filter capacitors incorporated in the high-voltage inverter increases. As a solution to this problem, there is a method of removing filter capacitors that have excess capacity. However, there are cases where it is not possible to remove the filter capacitor due to the specifications, in order to be able to return it to the existing system, or for the reason that the filter capacitor cannot be removed easily due to its structure.
In this case, it is necessary to leave the filter capacitor, which is an excess capacity, in the device and electrically insulate it from the main circuit. Furthermore, insulated filter capacitors, like capacitors that are stored as replacement parts, have an increased risk of electric shock due to spontaneous charging, so it is necessary to short-circuit between the P and N terminals.

In short, in view of the above-mentioned point, when the built-in filter capacitor unit is incorporated into the high-voltage inverter device and the capacity of the capacitor built into the high-voltage inverter device is increased, in this embodiment, the filter capacitor P To easily realize a structure for insulating a terminal and an N terminal and at the same time short-circuiting a P terminal and an N terminal of a filter capacitor.
Specifically, as shown in FIG. 9, a filter capacitor non-incorporating unit 108 that does not incorporate a filter capacitor and a filter capacitor incorporating unit 107 that incorporates a filter capacitor (Fc) that cannot be removed due to specifications. When replacing the filter capacitor non-built-in unit 108 in FIG. 9 with the filter capacitor built-in unit 106 with a built-in filter capacitor (Fc) in FIG. do. Therefore, isolation of any capacitors on the circuit is required. In such a case, the isolation of the filter capacitor is performed safely.

A high voltage is applied to the main circuit of the high voltage inverter. Therefore, in order to insulate the filter capacitor, it is necessary to keep the P terminal and N terminal of the filter capacitor (Fc) away from the main circuit by keeping an appropriate insulation distance or taking measures such as inserting an insulator between them. There is Furthermore, it is necessary to short-circuit the P terminal and N terminal of the insulated filter capacitor (Fc) with a short-circuiting member (conductor) so that they have the same potential. FIG. 7 is a circuit diagram showing this.

FIG. 7 shows a state in which the P terminal side of the filter capacitor (Fc) is insulated (marked with x) and the P terminal and N terminal sides of the filter capacitor (Fc) are short-circuited (both terminals are connected).
It can be seen that when the filter capacitor (Fc) is not insulated, a circuit as shown in FIG.
FIG. 6 shows a state in which the filter capacitor (105/Fc in FIG. 8), which cannot be removed due to specifications, is energized.

Also, in this embodiment, the P terminal and the N terminal are short-circuited by a short-circuiting member (conductor) during storage of the additional filter capacitor built in a detachable unit according to specifications.

The details of this embodiment will be described below with reference to FIGS. 1 to 9. FIG.
First, consider the case where the filter capacitor 101 is isolated from the main circuit (not shown) of the high-voltage inverter device.
FIG. 1 is a schematic diagram of a high-voltage inverter device according to this embodiment.
A device main body 100 of the high-voltage inverter includes a filter capacitor 101 that cannot be removed from the device main body 100 due to specifications, and a filter capacitor 103 that can be removed from the device main body 100 due to specifications.

First, the main circuit P terminal 1031 and the N wiring 1032 connected to the P terminal and N terminal of the filter capacitor 101 are once removed.

Next, the short-circuiting device 104 is attached to the capacitor terminal portion of the filter capacitor 101 from which the main circuit P wiring 1031 and N wiring 1032 have been removed, that is, to the P terminal 1011 and N terminal 1012 .
Then, the short-circuit member (conductor) 1041 of the short-circuit device 104 short-circuits the P terminal 1011 and the N terminal 1012 of the filter capacitor 101 . The configuration of the shorting device 104 will be described later.
At this time, as a premise, the main circuit P wiring 1031 and the main circuit N wiring 1032 need to be composed of members such as flexible electric wires.

Next, either one of the main circuit P wiring 1031 and the main circuit N wiring 1032 removed from the filter capacitor 101, for example, the main circuit P wiring 1031 is placed on the short-circuiting member (conductor) 1041, and the insulating member (insulator) 1042 is provided. Attach to Attachment to the insulating member (insulator) 1042 is performed via a terminal (conductor bar) 10511, for example.
Thereby, the main circuit P wiring 1031 and the P terminal 1011 of the filter capacitor 101 can be insulated.
Also, the other main circuit N wiring 1032 is connected to a terminal (conductor bar) 10512 that connects to the N terminal 1012 of the filter capacitor 101 .
In this embodiment, it is assumed that the main circuit P wiring 1031 is insulated, but the main circuit N wiring 1032 may be insulated.

As described above, the main circuit and the filter capacitor 101 can be insulated, and the P terminal 1011 and the N terminal 1012 of the filter capacitor 101 can be short-circuited (see FIGS. 2 and 3). The details will be described below with reference to FIGS. 2 and 3. FIG.

2 shows the installation of main circuit P wiring 1031 and main circuit N wiring 1032, P terminal 1011 of filter capacitor 101, N terminal 1012, short circuit member 1041 of short circuit device 104, and insulating member 1042, which constitute the main circuit of the high-voltage inverter device. FIG. 3 is an external perspective view showing the state, and FIG. 3 is a diagram for explaining the connection relationship between the short circuit device 104, the filter capacitor 101, the main circuit P wiring 1031, and the main circuit N wiring 1032. As shown in FIG.

In the figure, the main circuit P wiring 1031 is fixed to an insulating member (insulator) 1042 of the short-circuit device 104 via a terminal 10511 with a fixture 1052 such as a bolt or nut.

The main circuit N wiring 1032 is fixed to the short-circuiting member (conductor) 1041 of the short-circuiting device 104 via the terminal 10512 by means of fasteners 1052 such as bolts and nuts.

A short-circuit member (conductor) 1041 of the short-circuit device 104 is fixed by a fixture 1052 such as a bolt or nut so as to come into contact with the P terminal 1011 and N terminal 1012 of the filter capacitor 101 inserted into the terminal insertion hole 1043 .

The short-circuiting member (conductor) 1041 constitutes a terminal short-circuit holding portion that holds the P terminal 1011 and the N terminal 1012 of the filter capacitor 101 , and the insulating member (insulator) 1042 is a wiring insulation holding portion that holds the main circuit P wiring 1031. configure.

FIG. 4 is an external perspective view showing an example of the short circuit device 104 according to this embodiment.
The shorting device 104 has one shorting member 1041 and a plurality of insulating members 1042 .

The short-circuit member 1041 short-circuits the P terminal 1011 and the N terminal 1012 of the filter capacitor 101, and is made of a plate-like conductor (conductive material). Short-circuit member 1041 includes a plurality of terminal insertion holes 1043 formed for inserting P terminal 1011 and N terminal 1012 of filter capacitor 101 .

The insulating member 1042 insulates the main circuit wirings 10 31 and 10 32 from the capacitor terminal portion of the filter capacitor 101 , and consists of, for example, a pair of insulators formed at one end of the short-circuit member 1041 .

Next, let us consider short-circuiting of the P/N terminals of the extension filter capacitor 103 in the unit 102 (power unit) which is detachable in terms of specifications and which incorporates the filter capacitor 103 .
At this time, it is necessary to short-circuit the P and N terminals of the built-in filter capacitor 103 in the detachable unit 102, which is detached from the high-voltage inverter device.
Therefore, the P and N terminals of the filter capacitor 103 inside the unit must be short-circuited by the short-circuiting device 104 (short-circuiting member) in the same way as when the filter capacitor 101 inside the high-voltage inverter is short-circuited. Likewise, the capacitor in the high-voltage inverter does not need to be short-circuited via a discharge resistor or the like.
Therefore, there is no problem as long as the conductor has a shape that allows short-circuiting between the P terminal and the N terminal of the capacitor terminal portion.

The details will be described below with reference to FIGS. 1 to 4. FIG.
In FIG. 1, an apparatus main body 100 has an internal filter capacitor 101 that cannot be removed due to specifications, and an additional filter capacitor 103 incorporated in a unit 102 that can be removed due to specifications.

The detachable unit 102 according to specifications has a unit P terminal 1021 and a unit N terminal 1022 made of conductors attached to the P terminal and N terminal of the filter capacitor 103 for addition in an electrically conductive state. The unit P terminal 1021 and the unit N terminal 1022 are designed to be exposed from the detachable unit 102 as shown in the drawing.

First, it is considered that the unit 102, which is detachable in terms of specifications, is detached from the apparatus body 100 together with the built-in additional filter capacitor 103 for maintenance or long-term storage.
At this time, a short-circuiting device 104 shown in FIG. 4 is prepared. In this embodiment, an insulating member 1042 made of an insulator is attached to the short-circuiting device 104. This is intended to share the insulating member 1042 and the short-circuiting member 1041 of the capacitor inside the high-voltage inverter. .
If the purpose is only to short-circuit the filter capacitor 103 built in the unit 102, the short-circuit device 104 as shown in FIG. In this case, the insulating member 1042 of the insulator can be eliminated.

As shown in FIG. 5, the shorting device 104 is attached to a unit P terminal 1021 and a unit N terminal 1022 provided in the unit 102 connected to the P terminal and N terminal of the additional filter capacitor 103 . Thereby, the P terminal and the N terminal of the additional filter capacitor 103 can be short-circuited.

According to the embodiment described above, the following effects can be expected.

When storing the unit 102 with a short-circuiting member 1041 for short-circuiting the P terminal and N terminal of the filter capacitor 103 for extension built in the unit 102 which is detachable due to specifications, the unit 102 is stored. By clearly indicating in the instruction manual, caution nameplate, etc. in advance that this member should be installed in a place corresponding to the P/N terminal of the filter capacitor 103 built in 102, the operator can install the member in the relevant place. You can install it without forgetting.
In instruction manuals and caution nameplates, for example, there are photographs showing the state of insulation, along with the message, "In addition to insulating the filter capacitor, it is necessary to short-circuit between P and N of the capacitor. is attached to the terminal of the capacitor, and the capacitor is isolated from the main circuit while short-circuiting between P and N of the capacitor.

In addition, while the voltage is being applied to the high-voltage inverter device, it is possible to safely short-circuit the P and N terminals of the filter capacitor 101, which cannot be removed due to specifications, while insulating the P and N terminals (terminal section). can.
The operation required at this time is a structure in which the P terminal and N terminal (capacitor terminal portion) of the filter capacitor 101 are simply inserted into the terminal insertion hole 1043 of the short circuit device 104 having the short circuit member 1041 and the insulating member 1042, that is, The short-circuiting device 104 has a terminal insertion hole 1043 formed in a short-circuiting member 1041 into which the P terminal 1011 and the N terminal 1012 of the filter capacitor 101 are inserted. If the main circuit P wiring 1031 and the main circuit N wiring 1032 connected to , are flexible members such as electric wires, they can be easily applied to the existing system without modification.

In addition, the P terminal and the N terminal can be safely short-circuited during long-term storage of the additional filter capacitor 103 incorporated in the unit 102 which is detachable due to specifications.
At that time, even though the filter capacitor 103 is built into the unit 102 and placed in a location that is not easily accessible, the unit P terminal connected to the capacitor P terminal, the unit N terminal (conductor) 1021, and the unit N terminal (conductor) 1021 , 1022 are exposed to the outer surface of the unit 102. By connecting the short circuit member 1041 to the unit P terminal and the unit N terminal (conductors) 1021 and 1022, the P terminal and N terminal of the capacitor itself are connected. The same effect can be obtained as when the short-circuit member 1041 is connected to the .

Further, by setting the short-circuiting device 104 to be attached to the interface between the unit 102 and the device main body 100 when the unit is stored, the short-circuiting device 104 and the device main body 100 interfere with each other when the unit 102 is attached to the main device 100. The risk of forgetting to attach the short-circuiting device 104 to the main unit 100 can be eliminated at the same time that the operator can notice the presence of the short-circuiting device 104 again.

Further, by adopting a structure in which the short-circuiting device 104 is attached to the unit 102 itself during storage of the unit 102, loss of the short-circuiting device 104 including the short-circuiting member 1041 can be prevented.
The short-circuiting device 104 is difficult to store and manage when removed from the device main body 100 or the unit 102 . For example, even if the short-circuiting device 104 is attached to the unit 102, if the operator does not know the presence of the short-circuiting device 104, the existence of the short-circuiting device 104 is forgotten, and the operator forgets to short-circuit even though the short-circuiting is required. There are risks. With respect to this risk, the risk of forgetting to short-circuit can be prevented by clearly indicating in advance, in an instruction manual or a caution nameplate, the locations of members to be attached in the unit 102 of the short-circuiting device 104 .

100 device main body 101 filter capacitor 102 detachable unit 103 filter capacitor built in detachable unit 104 short circuit device 1041 short circuit member (conductor)
1042 insulating member (insulator)
1043 Terminal insertion holes 106 and 107 Filter capacitor built-in unit 108 with built-in filter capacitor Filter capacitor non-built-in unit with no built-in filter capacitor

Claims (5)

In a short-circuiting device that short-circuits between the P terminal and the N terminal of a filter capacitor,
a terminal short-circuit holding unit that short-circuits the P terminal and the N terminal of the filter capacitor and holds the P terminal and the N terminal; and a main circuit P wiring connected to the P terminal and the P terminal or the N terminal. A short-circuiting device, comprising: a wiring insulation holding part that insulates the N terminal from the main circuit N wiring connected to the main circuit P wiring and holds the main circuit P wiring or the main circuit N wiring. A short circuiting device according to claim 1,
The terminal short-circuit holding unit,
It has a short-circuit member that short-circuits the P terminal and N terminal of the filter capacitor that cannot be removed from the device body due to specifications and the additional filter capacitor provided in the unit that can be removed from the device body due to specifications,
The wiring insulation holding part is
an insulating member for insulating the non-removable filter capacitor from the main circuit P wiring or the main circuit N wiring;
A short-circuiting device characterized by: A short-circuiting device according to claim 2,
The short-circuiting member is made of a plate-shaped conductor including a terminal insertion hole for inserting the P terminal and the N terminal of the filter capacitor,
The insulating member is made of an insulator,
A short-circuiting device characterized by: A terminal short-circuit holding unit that short-circuits the P terminal and the N terminal of the filter capacitor and holds the P terminal and the N terminal, and a main circuit P wiring connected to the P terminal and the P terminal or the N terminal. A short-circuiting device having a wiring insulation holding part that insulates the connected main circuit N wiring from the N terminal and holds the main circuit N wiring or the main circuit P wiring between the P terminal and the N terminal of the filter capacitor. A short-circuit method for short-circuiting the
Remove the main circuit P wiring and the main circuit N wiring from the P terminal and N terminal of the filter capacitor that cannot be taken out from the device main body,
The short-circuiting device is attached to the P terminal and the N terminal of the non-removable filter capacitor from which the main circuit P wiring and the main circuit N wiring are removed, and the non-removable filter capacitor is connected to the non-removable filter capacitor by the short-circuiting member in the terminal short-circuit holding portion of the shorting device. Short-circuit between the P terminal and N terminal of the filter capacitor,
When the detachable unit is taken out from the device main body, the P terminal and N terminal of the filter capacitor built in the unit are connected through the unit P terminal and the unit N terminal formed in the unit by the short circuit member in the terminal short circuit holding portion. A short-circuiting method characterized by short-circuiting between terminals. The short-circuiting method of claim 4 , wherein
Further, one of the main circuit P wiring and N wiring removed from the P terminal and N terminal of the filter capacitor that cannot be taken out is connected to the insulating member of the wiring insulation holding part,
connecting the other of the main circuit P wiring and N wiring to the P terminal or N terminal of the filter capacitor;
A short circuit characterized in that the non-removable filter capacitor is insulated from the main circuit P wiring or N wiring, and the P terminal and N terminal of the non-removable filter capacitor are short-circuited. Method.

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