Load testing apparatus

Abstract

To provide a load testing device.SOLUTION: The load testing device includes a first resistor unit having a plurality of first resistors, and a first cooling unit including a cooling device that sends cooling air to the plurality of first resistors. A diffusion part for diffusing cooling air is provided between the first cooling part and the first resistance unit, the diffusion part is composed of an opening / closing door for closing an exhaust port of the first cooling part by energization, and the opening / closing door is opened by the cooling air discharged from the first cooling part. Alternatively, the exhaust port of the first resistance unit is provided with an exhaust port hood, and the exhaust port hood is biased to be in a closed state and is brought into an open state by the cooling air from the first cooling unit.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a load testing device. [Background technology]

[0002] Conventionally, as disclosed in Patent Document 1, a load testing device for performing a load test on a generator has been proposed, which is made up of a plurality of cooling devices and a plurality of resistance units. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 09-15307 Summary of the Invention [Problem to be solved by the invention]

[0004] However, it was not adequately adapted to various load tests.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a load testing apparatus that can handle a variety of load tests. [Means for solving the problem]

[0006] A load testing device according to the present invention includes a first resistor unit having a plurality of first resistors, and a first cooling section including a cooling device that sends cooling air to the plurality of first resistors. A load testing device in which a diffusion section for diffusing cooling air is provided between the first cooling section and the first resistance unit, and the diffusion section is composed of an opening / closing door that closes the exhaust port of the first cooling section when biased, and the opening / closing door is opened by the cooling air discharged from the first cooling section, or an exhaust port hood is provided at the exhaust port of the first resistance unit, and the exhaust port hood is biased to a closed state and opened by the cooling air from the first cooling section.

[0007]

[0008]

[0009]

[0010]

[0011]

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030] [Effects of the Invention]

[0031] As described above, according to the present invention, it is possible to provide a load testing device that can handle a variety of load tests. [Brief explanation of the drawings]

[0032] [Figure 1] 1 is a perspective view of a load testing device according to an embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view of an area including a cooling section and a resistance unit. [Figure 3] FIG. 1 is an exploded perspective view of an area including a cooling section and a resistance unit. [Figure 4] FIG. 2 is an exploded perspective view of an area including a cooling section, a first housing, a first resistance unit, a second resistance unit, and a third resistance unit. [Figure 5] FIG. 1 is a schematic diagram illustrating a configuration of a load testing device. [Figure 6] FIG. 10 is a diagram showing wiring of a resistor group and a switching device in a load testing device. [Figure 7] FIG. 10 is a perspective view of a load testing device provided with a first exhaust port hood and a first intake port hood. [Figure 8] FIG. 1 is a perspective view of a load testing device provided with a roof portion, a base portion, a first exhaust port hood, and a first intake port hood. [Figure 9] 10 is an exploded perspective view of a region including a cooling section including a diffusion section, a first housing, a first resistor unit, a second resistor unit, and a third resistor unit including protrusions, and an insulator. FIG. [Figure 10] FIG. 10 is an exploded perspective view of a region including a cooling section including a diffusion section and a resistance unit including a protrusion section. [Figure 11] 10 is an exploded perspective view of a region including a cooling section including a diffusion section configured with an opening / closing door and a resistance unit including a protrusion portion. FIG. [Figure 12] FIG. 10 is a perspective view of a load testing device provided with a second exhaust port hood and a second intake port hood. [Figure 13] FIG. 10 is a perspective view of a load testing device provided with a roof portion, a second exhaust port hood, and a second intake port hood. [Figure 14]FIG. 1 is a perspective view of a load testing device including a first resistor group and a second resistor group including a relay section. [Figure 15] FIG. 1 is a perspective view of a load testing device including a first resistor group and a second resistor group that does not include a relay section. [Figure 16] 1 is a schematic diagram of a load testing device including a first resistor group and a second resistor group that does not include a relay section, showing in detail the portion where the first resistor group is located. [Figure 17] 1 is a schematic diagram of a load testing device including a first resistor group and a second resistor group that does not include a relay section, showing in detail the portion where the second resistor group is located. [Figure 18] FIG. 10 is an exploded perspective view of a region including a cooling section including a constriction section and a resistance unit including a protrusion section. [Figure 19] 10 is an exploded perspective view of a region including a cooling section including a constricted section provided with a diffusion section and a resistance unit including a protrusion section; FIG. [Figure 20] FIG. 10 is an exploded perspective view of a region including a cooling section including a diffusion section and a resistance unit including a rod-shaped protruding region. [Figure 21] FIG. 10 is an exploded perspective view of a region including a cooling section including a diffusion section and a resistance unit including a frame-shaped protruding region. DETAILED DESCRIPTION OF THE INVENTION

[0033] The present embodiment will be described below with reference to the drawings. The embodiments are not limited to the following embodiments. Furthermore, the content described in one embodiment is generally applicable to other embodiments as well. Furthermore, the embodiments and modifications can be combined as appropriate. The dry load testing device 1 of this embodiment includes a resistance unit 30, a cooling section 50, a control section 70, and a relay section 90 (see FIGS. 1 to 6).

[0034] The resistor unit 30 includes a first housing 2a, a first resistor unit 30a, a second resistor unit 30b, and a third resistor unit 30c. The first housing 2a covers the first resistor unit 30a, the second resistor unit 30b, and the third resistor unit 30c. The cooling section 50 has a second housing 2b, a first cooling section 50a, a second cooling section 50b, and a third cooling section 50c. The second housing 2b covers the first cooling section 50a, the second cooling section 50b, and the third cooling section 50c.

[0035] In addition, the first resistance unit 30a and the first cooling section 50a will be described as the first load testing section 1a, the second resistance unit 30b and the first cooling section 50b will be described as the second load testing section 1b, and the third resistance unit 30c and the third cooling section 50c will be described as the third load testing section 1c.

[0036] To explain the directions, one of the horizontal directions will be referred to as the x direction (left-right direction, first direction), the direction perpendicular to the x direction will be referred to as the y direction (vertical direction, second direction), and the horizontal direction perpendicular to the x and y directions will be referred to as the z direction (front-back direction, third direction). The control unit 70, the relay unit 90, and the load test unit are arranged in the x direction. The first load testing unit 1a, the second load testing unit 1b, and the third load testing unit 1c are arranged in the y direction. The cooling section 50 and the resistance unit 30 in the load testing section are aligned in the z direction. This arrangement allows the components of the load testing device 1 to be arranged efficiently in a small space, making it easy to assemble each part, and to wire from the control unit 70 to the resistance unit 30 and from the control unit 70 to the cooling unit 50.

[0037] 1, 7, 12, 14, and 15, parts that cannot be seen from the outside are not shown. In addition, a solid line is shown between the third housing 2c and the fourth housing 2d to indicate the boundary between the control unit 70 and the relay unit 90, but the third housing 2c and the fourth housing 2d may also be configured as a single unit. In FIG. 2, resistors are not shown, and outlines of the first to third resistance units 30a to 30c and the first to sixth cooling devices 53a to 53f that cannot be seen from the outside are shown by dotted lines. In Figure 3, except for the terminals on the relay section 90 side (areas protruding in the x direction from the first holding section 31a to the third holding section 31c), parts of the resistor that cannot be seen from the outside are not shown, and the outline parts of the first resistor unit 30a to the third resistor unit 30c and the first cooling device 53a to the sixth cooling device 53f that cannot be seen from the outside are shown with dotted lines. In Figures 4 and 9, for the first resistor unit 30a and the second resistor unit 30b, the parts of the resistor that cannot be seen from the outside are omitted, and for the third resistor unit 30c, the parts of the resistor that cannot be seen from the outside are shown with dotted lines. In addition, in FIGS. 4 and 9, the outlines of the first to sixth cooling devices 53a to 53f, which cannot be seen from the outside, are shown by dotted lines.

[0038] In addition, in order to show the positional relationship between the cooling section 50 and the resistance unit 30, Figures 3, 4 and 9 show the housing (first housing 2a) of the first resistance unit 30a, the second resistance unit 30b and the third resistance unit 30c and the housing (second housing 2b) of the first cooling section 50a, the second cooling section 50b and the third cooling section 50c in a separated state, but after assembly, the first housing 2a and the second housing 2b are fixed as shown in Figures 1 and 2. Furthermore, the first housing 2a and the second housing 2b may be integrally formed. In FIGS. 8 and 13, the outline of the first housing 2a and other parts hidden by the roof portion 2e is shown by dotted lines, and other parts that cannot be seen from the outside are not shown. In addition, in Figures 10, 11, 18, 20 and 21, the front side portion of the first housing 2a is omitted so that the internal structure can be seen, and parts of the resistor that cannot be seen from the outside are not shown except for the terminals on the relay unit 90 side (areas protruding in the x direction from the first holding portion 31a to the third holding portion 31c), and the outline portions of the first resistor unit 30a to the third resistor unit 30c and the first cooling device 53a to the sixth cooling device 53f that cannot be seen from the outside are shown with dotted lines. In addition, in Figure 19, the side portion on the front side of the first housing 2a is omitted so that the internal structure can be seen, and parts of the resistor that are not visible from the outside are not shown, except for the terminals on the relay unit 90 side (the areas protruding in the x direction from the first holding portion 31a to the third holding portion 31c).The first resistor unit 30a to the third resistor unit 30c are shown with dotted lines, and only the outline portions of the first cooling device 53a to the sixth cooling device 53f that are visible from the outside are shown with solid lines.

[0039] The configuration of the first load testing section 1a will be described. The first load testing section 1a is used to perform a load test on one of the three phases (in this embodiment, the T phase) of the power supply under test (a three-phase AC generator), and has a first resistance unit 30a and a first cooling section 50a (a first cooling device 53a, a second cooling device 53b).

[0040] The first cooling section 50a and the first resistance unit 30a are aligned in the z direction so that the intake port of the first resistance unit 30a (first opening 31a1 of the first holding section 31a) faces the exhaust port of the first cooling section 50a (first cooling device 53a, second cooling device 53b).

[0041] The configuration of the second load testing section 1b will be described. The second load testing section 1b is used to perform a load test on one of the three phases (in this embodiment, the S phase) of the power supply under test (a three-phase AC generator), and is placed on top of the first load testing section 1a, and has a second resistance unit 30b and a second cooling section 50b (a third cooling device 53c, a fourth cooling device 53d).

[0042] The second cooling section 50b and the second resistance unit 30b are arranged in the z direction so that the intake port of the second resistance unit 30b (second opening 31b1 of the second holding section 31b) faces the exhaust port of the second cooling section 50b (third cooling device 53c, fourth cooling device 53d).

[0043] The configuration of the third load testing section 1c will be described. The third load testing section 1c is used to perform a load test on one of the three phases (in this embodiment, the R phase) of the power supply under test (a three-phase AC generator), and is placed on the second load testing section 1b, and has a third resistance unit 30c and a third cooling section 50c (a fifth cooling device 53e and a sixth cooling device 53f).

[0044] The third cooling section 50c and the third resistance unit 30c are arranged in the z direction so that the intake port of the third resistance unit 30c (the third opening 31c1 of the third holding section 31c) faces the exhaust port of the third cooling section 50c (the fifth cooling device 53e, the sixth cooling device 53f).

[0045] Electrical connections for the resistor groups of the first resistor unit 30a (first W-phase resistor group RW1 to third W-phase resistor group RW3), the resistor groups of the second resistor unit 30b (first V-phase resistor group RV1 to third V-phase resistor group RV3), and the resistor groups of the third resistor unit 30c (first U-phase resistor group RU1 to third U-phase resistor group RU3) are made using connection members 3 such as cables or connection bars from the power supply terminal unit 73 of the control unit 70 (see Figures 5 and 6).

[0046] The switching devices of the first resistor unit 30a (first W-phase switching device SW1 to third W-phase switching device SW3), the switching devices of the second resistor unit 30b (first V-phase switching device SV1 to third V-phase switching device SV3), and the switching devices of the third resistor unit 30c (first U-phase switching device SU1 to third U-phase switching device SU3) are controlled using a cable (control line 4) from the control terminal unit 75 of the control unit 70.

[0047] The control line 4 is a cable used to control the on / off of the switching devices (SU1 to SU3, SV1 to SV3, SW1 to SW3) provided in the relay unit 90 from the control unit 70 (not shown in the perspective views of Figures 1 to 4 and 7 to 15).

[0048] The configuration of the first resistor unit 30a will be described. The first resistor unit 30a includes a plurality of resistors (first resistors), a first holding portion 31a that holds the plurality of first resistors, and a first insulator 33a.

[0049] The resistors of the first resistor unit 30a are held by the side surfaces of a first holding portion 31a which is formed of a frame body with openings on the front and back sides. The front opening of the first holding part 31a functions as an exhaust port, and the rear opening (first opening 31a1, the surface facing the first cooling part 50a) functions as an intake port. Insulators (first insulators 33a) are provided at the four corners of the lower surface of the first holding portion 31a. The first holding portion 31a is placed on the bottom surface of the first housing 21 via the first insulator 33a.

[0050] The multiple resistors (first resistors) included in the first resistor unit 30a are arranged in one or more rows in the y direction, with multiple rod-shaped resistors parallel to the x direction lined up at predetermined intervals in the z direction, and are used to perform a load test on the T phase of a power supply under test, such as a three-phase AC generator, connected via the power terminal unit 73 of the control unit 70.

[0051] Of the multiple resistors (first resistors) included in the first resistor unit 30a, one or more resistors connected in series or in parallel form a resistor group, and the resistor group is connected in parallel with other resistor groups, and a switching device is provided for controlling the on / off of power supply for each resistor group. A load test is carried out while changing the number of resistor groups to which voltage is applied from the T phase of the power supply under test.

[0052] In this embodiment, the first resistor unit 30a is configured such that six resistor rows are arranged in the y direction, each row including eight rod-shaped resistors parallel to the x direction and arranged at predetermined intervals in the z direction. In addition, the resistor group including 16 resistors in the top two rows constitutes the first W-phase resistor group RW1, the resistor group including 16 resistors in the middle two rows constitutes the second W-phase resistor group RW2, and the resistor group including 16 resistors in the bottom two rows constitutes the third W-phase resistor group RW3.

[0053] In addition, a first W-phase switching device SW1 is provided as a switching device that controls the on / off of the power supply to the first W-phase resistor group RW1, a second W-phase switching device SW2 is provided as a switching device that controls the on / off of the power supply to the second W-phase resistor group RW2, and a third W-phase switching device SW3 is provided as a switching device that controls the on / off of the power supply to the third W-phase resistor group RW3.

[0054] The first W-phase switching device SW1 to the third W-phase switching device SW3 are housed in a relay unit 90 and connected to a control terminal unit 75 of the control unit 70 via a control line 4, and are controlled to be on or off in response to the on / off operation of an operating unit 71 of the control unit 70.

[0055] The configuration of the second resistor unit 30b will be described. The second resistor unit 30b includes a plurality of resistors (second resistors), a second holding portion 31b that holds the plurality of second resistors, and a second insulator 33b.

[0056] The resistors of the second resistor unit 30b are held by the side surfaces of a second holding portion 31b which is formed of a frame body with openings on the front and back sides. The front opening of the second holding part 31b functions as an exhaust port, and the rear opening (second opening 31b1, the surface facing the second cooling part 50b) functions as an intake port. Insulators (second insulators 33b) are provided at the four corners of the lower surface of the second holding portion 31b. The second holding portion 31b is placed on the upper surface of the first holding portion 31a of the first resistor unit 30a via the second insulator 33b.

[0057] The multiple resistors (second resistors) included in the second resistor unit 30b are arranged in one or more rows in the y direction, with multiple rod-shaped resistors parallel to the x direction lined up at predetermined intervals in the z direction, and are used to perform a load test on the S phase of a power supply under test, such as a three-phase AC generator, connected via the power terminal unit 73 of the control unit 70.

[0058] Of the multiple resistors (second resistors) included in the second resistor unit 30b, one or more resistors connected in series or parallel form a resistor group, and the resistor group is connected in parallel with other resistor groups, and a switching device is provided for controlling the on / off of power supply for each resistor group. A load test is carried out while changing the number of resistor groups to which voltage is applied from the S phase of the power supply under test.

[0059] In this embodiment, the second resistor unit 30b is configured such that six resistor rows are arranged in the y direction, each row including eight rod-shaped resistors parallel to the x direction and arranged at predetermined intervals in the z direction. In addition, the resistor group including 16 resistors in the top two rows constitutes the first V-phase resistor group RV1, the resistor group including 16 resistors in the middle two rows constitutes the second V-phase resistor group RV2, and the resistor group including 16 resistors in the bottom two rows constitutes the third V-phase resistor group RV3.

[0060] In addition, a first V-phase switching device SV1 is provided as a switching device that controls on / off the power supply to the first V-phase resistor group RV1, a second V-phase switching device SV2 is provided as a switching device that controls on / off the power supply to the second V-phase resistor group RV2, and a third V-phase switching device SV3 is provided as a switching device that controls on / off the power supply to the third V-phase resistor group RV3.

[0061] The first V-phase switching device SV1 to the third V-phase switching device SV3 are housed in the relay unit 90 and connected to the control terminal unit 75 of the control unit 70 via the control line 4, and are controlled to be on or off in response to the on or off operation of the operating unit 71 of the control unit 70.

[0062] The configuration of the third resistor unit 30c will be described. The third resistor unit 30c includes a plurality of resistors (third resistors), a third holding portion 31c that holds the plurality of third resistors, and a third insulator 33c.

[0063] The resistors of the third resistor unit 30c are held by the side surfaces of a third holding portion 31c which is formed of a frame body with openings on the front and back sides. The front opening of the third holding part 31c functions as an exhaust port, and the rear opening (third opening 31c1, the surface facing the third cooling part 50c) functions as an intake port. Insulators (third insulators 33c) are provided at the four corners of the lower surface of the third holding portion 31c. The third holding portion 31c is placed on the upper surface of the second holding portion 31b of the second resistor unit 30b via the third insulator 33c.

[0064] In this embodiment, the first to third insulators 33a to 33c are shown to have a rectangular parallelepiped shape, but the shape of the insulators is not limited to a rectangular parallelepiped shape, and may be another shape such as a substantially cylindrical shape.

[0065] The multiple resistors (third resistors) included in the third resistor unit 30c are arranged in one or more rows in the y direction, with multiple rod-shaped resistors parallel to the x direction lined up at predetermined intervals in the z direction, and are used to perform a load test on the R phase of a power supply under test, such as a three-phase AC generator, connected via the power terminal unit 73 of the control unit 70.

[0066] Of the multiple resistors (third resistors) included in the third resistor unit 30c, one or more resistors connected in series or parallel form a resistor group, and the resistor group is connected in parallel with other resistor groups, and a switching device is provided for controlling the on / off of power supply for each resistor group. A load test is carried out while changing the number of resistor groups to which voltage is applied from the R phase of the power supply under test.

[0067] In this embodiment, the third resistor unit 30c is configured such that six resistor rows are arranged in the y direction, each row including eight rod-shaped resistors parallel to the x direction and arranged at predetermined intervals in the z direction. In addition, the resistor group including 16 resistors in the top two rows constitutes the first U-phase resistor group RU1, the resistor group including 16 resistors in the middle two rows constitutes the second U-phase resistor group RU2, and the resistor group including 16 resistors in the bottom two rows constitutes the third U-phase resistor group RU3.

[0068] In addition, a first U-phase switching device SU1 is provided as a switching device that controls the on / off of the power supply to the first U-phase resistor group RU1, a second U-phase switching device SU2 is provided as a switching device that controls the on / off of the power supply to the second U-phase resistor group RU2, and a third U-phase switching device SU3 is provided as a switching device that controls the on / off of the power supply to the third U-phase resistor group RU3.

[0069] The first U-phase switching device SU1 to the third U-phase switching device SU3 are housed in a relay unit 90 and connected to a control terminal unit 75 of the control unit 70 via a control line 4, and are controlled to be on or off in response to the on or off operation of an operating unit 71 of the control unit 70.

[0070] Due to the neutral point connection, the first U-phase resistor group RU1, the first V-phase resistor group RV1, the first W-phase resistor group RW1, the second U-phase resistor group RU2, the second V-phase resistor group RV2, the second W-phase resistor group RW2, the third U-phase resistor group RU3, the third V-phase resistor group RV3, and the third W-phase resistor group RW3 are short-circuited.

[0071] In this embodiment, as an example, a configuration will be described in which each of the first resistor unit 30a to the third resistor unit 30c has three resistor groups (RW1 to RW3, RV1 to RV3, RU1 to RU3) and switching devices (SW1 to SW3, SV1 to SV3, SU1 to SU3) that control the on / off of power supply to each resistor group, but the number of resistor groups and switching devices is not limited to three.

[0072] Furthermore, the resistor arrays in the first resistor unit 30a to the third resistor unit 30c have been described as being formed by multiple rod-shaped resistors parallel to the x direction lined up at predetermined intervals in the y direction, but may also be formed by multiple rod-shaped resistors parallel to the y direction lined up at predetermined intervals in the x direction.

[0073] The configuration of the first cooling section 50a will be described. The first cooling section 50a has a first cooling device 53a and a second cooling device 53b.

[0074] The front surface of the first cooling section 50a (the surface facing the first opening 31a1 of the first holding section 31a of the first resistance unit 30a) is opened as an exhaust port, and the rear surface is opened as an intake port.

[0075] The first cooling device 53a and the second cooling device 53b are cooling fans or the like that expel air (see the dashed arrow in Figure 2) in the horizontal direction (z direction), and send the air introduced from the intake port through the exhaust port to the first resistance unit 30a.

[0076] The first cooling device 53a and the second cooling device 53b are arranged side by side in the x direction. The first cooling device 53a cools the area of ​​the resistor of the first resistor unit 30a that is closer to the relay section 90. The second cooling device 53b cools the area of ​​the resistor of the first resistor unit 30a that is away from the relay section 90.

[0077] In order for the cooling air from the plurality of cooling devices of the first cooling section 50a to reach almost the entire area of ​​the first opening 31a1 of the first holding portion 31a of the first resistor unit 30a, it is desirable to determine the dimensions of each member so that the width in the x direction (diameter of the area) w1 of the area from which the cooling air is discharged in each of the two or more cooling devices (first cooling device 53a, second cooling device 53b) of the first cooling section 50a is shorter than two-thirds of the width in the x direction w2 of the area of ​​the resistor of the first resistor unit 30a that is covered by the first holding portion 31a (see FIG. 4, w1 <w2×2 / 3)。

[0078] The configuration of the second cooling section 50b will be described. The second cooling section 50b has a third cooling device 53c and a fourth cooling device 53d.

[0079] The front surface of the second cooling section 50b (the surface facing the second opening 31b1 of the second holding section 31b of the second resistance unit 30b) opens as an exhaust port, and the rear surface opens as an intake port.

[0080] The third cooling device 53c and the fourth cooling device 53d are cooling fans or the like that expel air (see the dashed arrow in Figure 2) in the horizontal direction (z direction), and send the air introduced from the intake port to the second resistance unit 30b via the exhaust port.

[0081] The third cooling device 53c and the fourth cooling device 53d are arranged side by side in the x direction. The third cooling device 53c cools the area of ​​the resistor of the second resistor unit 30b that is closer to the relay section 90. The fourth cooling device 53d cools the area of ​​the resistor of the second resistor unit 30b that is away from the relay section 90.

[0082] In order for the cooling air from the plurality of cooling devices of the second cooling section 50b to reach almost the entire area of ​​the second opening 31b1 of the second holding portion 31b of the second resistor unit 30b, it is desirable to determine the dimensions of each member so that the width in the x direction (diameter of the area) w1 of the area from which the cooling air is discharged in each of the two or more cooling devices (third cooling device 53c, fourth cooling device 53d) of the second cooling section 50b is shorter than two-thirds of the width in the x direction w2 of the area covered by the second holding portion 31b of the resistor of the second resistor unit 30b (w1 <w2×2 / 3)。

[0083] The second cooling section 50b is provided above the first cooling section 50a.

[0084] The configuration of the third cooling section 50c will be described. The third cooling section 50c includes a fifth cooling device 53e and a sixth cooling device 53f.

[0085] The front surface of the third cooling section 50c (the surface facing the third opening 31c1 of the third holding section 31c of the third resistance unit 30c) opens as an exhaust port, and the rear surface opens as an intake port.

[0086] The fifth cooling device 53e and the sixth cooling device 53f are cooling fans or the like that expel air (see the dashed arrow in Figure 2) in the horizontal direction (z direction), and send the air introduced through the intake port to the third resistance unit 30c via the exhaust port.

[0087] The fifth cooling device 53e and the sixth cooling device 53f are arranged side by side in the x direction. The fifth cooling device 53e cools the area of ​​the resistor of the third resistor unit 30c that is closer to the relay section 90. The sixth cooling device 53f cools the area of ​​the resistor of the third resistor unit 30c that is away from the relay section 90.

[0088] In order for the cooling air from the plurality of cooling devices of the third cooling section 50c to reach almost the entire area of ​​the third opening 31c1 of the third holding portion 31c of the third resistor unit 30c, it is desirable to determine the dimensions of each member so that the width in the x direction (diameter of the area) w1 of the area from which the cooling air is discharged in each of the two or more cooling devices (fifth cooling device 53e, sixth cooling device 53f) of the third cooling section 50c is shorter than two-thirds of the width in the x direction w2 of the area covered by the third holding portion 31c of the resistor of the third resistor unit 30c (w1 <w2×2 / 3)。

[0089] The third cooling section 50c is provided above the second cooling section 50b.

[0090] The first to sixth cooling devices 53a to 53f may be attached to a housing (second housing 2b) that covers the first to sixth cooling devices 53a to 53f, or may be attached to the first housing 2a.

[0091] The configuration of the control unit 70 will be described. The control unit 70 includes a third housing 2 c, an operation unit 71 , a power supply terminal unit 73 , a control terminal unit 75 , and a power supply control unit 77 . The operation unit 71, the power supply terminal unit 73, the control terminal unit 75, and the power supply control unit 77 are housed in a third housing 2c (housing for the control unit 70). The third housing 2c covers the operation unit 71, the power supply terminal unit 73, the control terminal unit 75, and the power supply control unit 77.

[0092] The switching devices (SW1 to SW3, SV1 to SV3, SU1 to SU3) of the first resistor unit 30a to the third resistor unit 30c, the first cooling device 53a to the fifth cooling device 53e, and the power supply control unit 77 are driven by a power supply (power supply for driving the load testing device) separate from the power supply under test (see Figure 5). Operation of the operation unit 71, cable connection between the operation unit 71 and the power supply for driving the load test device, and cable connection between the power supply terminal unit 73 and the power supply under test are performed with the door provided on the third housing 2c open.

[0093] The operation unit 71 has a mode switch MS, a fan switch FS, and a first operation switch S1 to a third operation switch S3 (not shown).

[0094] The mode switch MS is a rotary or sliding (or toggle or push button) operating switch used to turn the load testing device 1 on or off, but may also be configured to be used to select the type of power supply to be tested (switch modes).

[0095] When a load test is to be performed, the mode switch MS is set to the ON operating position. When the load test device 1 is to be turned off, the mode switch MS is set to the OFF operating position.

[0096] The fan switch FS is a slide-type (or toggle-type or push-button-type) operation switch that controls the on / off of the first to sixth cooling devices 53a to 53f when the mode switch MS is in the on state. The fan switch FS may be omitted, and the first to sixth cooling devices 53a to 53f may operate when the mode switch MS is set to the on operation position.

[0097] The first operation switch S1 to the third operation switch S3 are slide-type (or toggle-type or push-button-type) operation switches for controlling on / off of the switching devices (first W-phase switching device SW1 to third W-phase switching device SW3) of the resistor groups (first W-phase resistor group RW1 to third W-phase resistor group RW3) of the first resistor unit 30a, the switching devices (first V-phase switching device SV1 to third V-phase switching device SV3) of the resistor groups (first V-phase resistor group RV1 to third V-phase resistor group RV3) of the second resistor unit 30b, and the switching devices (first U-phase switching device SU1 to third U-phase switching device SU3) of the resistor groups (first U-phase resistor group RU1 to third U-phase resistor group RU3) of the third resistor unit 30c.

[0098] When the mode switch MS is in the on state and the first operating switch S1 is turned on, the first W-phase switching device SW1, the first V-phase switching device SV1, and the first U-phase switching device SU1 are turned on (conducting), allowing current to flow from the T-phase of the power supply under test connected to the load testing device 1 via the W-phase terminal WT to the first W-phase resistor group RW1, allowing current to flow from the S-phase of the power supply under test connected to the load testing device 1 via the V-phase terminal VT to the first V-phase resistor group RV1, and allowing current to flow from the R-phase of the power supply under test connected to the load testing device 1 via the U-phase terminal UT to the first U-phase resistor group RU1.

[0099] The same is true for the second operating switch S2 to the third operating switch S3; when the mode switch MS is in the on state and is turned on, the switching device of the corresponding resistor group is turned on (conducting), allowing current to flow through the resistor group from the power supply under test connected to the load testing device 1 via the W-phase terminal WT, V-phase terminal VT, and U-phase terminal UT.

[0100] When the mode switch MS is set to the ON operating position and the fan switch FS is set to the ON operating position, the first cooling device 53a to the sixth cooling device 53f are driven, and the on / off control of the switching devices of each resistor group of the first resistor unit 30a to the third resistor unit 30c is performed based on the operating states of the first operating switch S1 to the third operating switch S3.

[0101] The power supply terminal section 73 is a terminal for connecting a power supply to be tested, and has a U-phase terminal UT, a V-phase terminal VT, and a W-phase terminal WT used for connecting to a three-phase AC generator.

[0102] When performing a load test on a three-phase AC generator, the cables from the R, S, and T phases of the three-phase AC generator are connected to the U-phase terminal UT, V-phase terminal VT, and W-phase terminal WT, respectively.

[0103] The control terminal unit 75 has terminals for connecting the control lines 4 to the switching devices of the relay unit 90 (the first W-phase switching device SW1 to the third W-phase switching device SW3, the first V-phase switching device SV1 to the third V-phase switching device SV3, and the first U-phase switching device SU1 to the third U-phase switching device SU3).

[0104] When the control terminal unit 75 is connected to the switching devices (first W-phase switching device SW1 to third W-phase switching device SW3, first V-phase switching device SV1 to third V-phase switching device SV3, and first U-phase switching device SU1 to third U-phase switching device SU3) of the relay unit 90 via the control line 4, the first W-phase switching device SW1 to third W-phase switching device SW3, first V-phase switching device SV1 to third V-phase switching device SV3, and first U-phase switching device SU1 to third U-phase switching device SU3 are on / off controlled according to the on / off states of the first operation switch S1 to third operation switch S3.

[0105] For example, when the mode switch MS and the fan switch FS are set to the on operating position, the second operating switch S2 is turned on, and the first operating switch S1 and the third operating switch S3 are turned off, the second W-phase switching device SW2, the second V-phase switching device SV2, and the second U-phase switching device SU2 are turned on, and the other switching devices are turned off.

[0106] At this time, if cables from the R phase, S phase, and T phase of the three-phase AC generator are connected to the U-phase terminal UT, V-phase terminal VT, and W-phase terminal WT, respectively, a state is created in which current from the R phase of the three-phase AC generator can flow through the resistors of the second U-phase resistor group RU2, current from the S phase of the three-phase AC generator can flow through the resistors of the second V-phase resistor group RV2, and current from the T phase of the three-phase AC generator can flow through the resistors of the second W-phase resistor group RW2.

[0107] The power supply control unit 77 is a device such as a vacuum circuit breaker that controls the power supply from the power supply under test to the first resistor unit 30a to the third resistor unit 30c depending on the on / off state of the mode switch MS and the fan switch FS (cutting off the power supply when at least one of the mode switch MS and the fan switch FS is off).

[0108] Specifically, the power supply control unit 77 is arranged on the lines extending from the U-phase terminal UT to the resistors of the first U-phase resistor group RU1 to the third U-phase resistor group RU3, the line extending from the V-phase terminal VT to the resistors of the first V-phase resistor group RV1 to the third V-phase resistor group RV3, and the line extending from the W-phase terminal WT to the resistors of the first W-phase resistor group RW1 to the third W-phase resistor group RW3, and cuts off these three lines via a relay (not shown) when at least one of the mode switch MS and the fan switch FS is turned off.

[0109] The configuration of the relay section 90 will be described. Relay unit 90 has a fourth housing 2d, first W-phase switching device SW1 to third W-phase switching device SW3, first V-phase switching device SV1 to third V-phase switching device SV3, and first U-phase switching device SU1 to third U-phase switching device SU3. The fourth housing 2d covers the first through third W-phase switching devices SW1 through SW3, the first through third V-phase switching devices SV1 through SV3, and the first through third U-phase switching devices SU1 through SU3.

[0110] In this embodiment, the first U-phase switching device SU1 is arranged between the power supply control unit 77 and the first U-phase resistor group RU1, the second U-phase switching device SU2 is arranged between the power supply control unit 77 and the second U-phase resistor group RU2, and the third U-phase switching device SU3 is arranged between the power supply control unit 77 and the third U-phase resistor group RU3 (see Figure 6). In addition, the first V-phase switching device SV1 is arranged between the power supply control unit 77 and the first V-phase resistor group RV1, the second V-phase switching device SV2 is arranged between the power supply control unit 77 and the second V-phase resistor group RV2, and the third V-phase switching device SV3 is arranged between the power supply control unit 77 and the third V-phase resistor group RV3. In addition, the first W-phase switching device SW1 is arranged between the power supply control unit 77 and the first W-phase resistor group RW1, the second W-phase switching device SW2 is arranged between the power supply control unit 77 and the second W-phase resistor group RW2, and the third W-phase switching device SW3 is arranged between the power supply control unit 77 and the third W-phase resistor group RW3.

[0111] However, each switching device may be arranged between the short-circuit point of the resistor group and the resistor group itself. For example, the first U-phase switching device SU1 is arranged between the first U-phase resistor group RU1 and the point where the first U-phase resistor group RU1, the first V-phase resistor group RV1, and the first W-phase resistor group RW1 are short-circuited.

[0112] The fourth housing 2d has an opening on the side when viewed from the x direction, and cables for connecting electrical components included in the resistance unit 30, cooling section 50, control section 70, and relay section 90 are made through the opening area. For this reason, a first opening 2a1 for passing at least a cable is provided on the surface of the first housing 2a that comes into contact with the fourth housing 2d. Furthermore, a second opening 2b1 for passing at least a cable is provided on the surface of the second housing 2b that contacts the fourth housing 2d. Furthermore, at least an opening for passing a cable is provided on the surface of the third housing 2c that contacts the fourth housing 2d.

[0113] The fourth housing 2d houses switching devices (first W-phase switching device SW1 to third W-phase switching device SW3, first V-phase switching device SV1 to third V-phase switching device SV3, and first U-phase switching device SU1 to third U-phase switching device SU3).

[0114] In this embodiment, a plurality of cooling devices are provided to cool one resistance unit (to send cooling air into the opening of one resistance unit). Therefore, compared to a configuration in which one cooling device cools one resistance unit, a cooling device with a smaller size and rated capacity can be used. Since the size and rated capacity of the cooling device can be reduced, even when multiple cooling devices are used, noise caused by the cooling devices can be reduced compared to a configuration in which one large cooling device is used.

[0115] Furthermore, since cooling air can be applied directly to many areas of the resistor group, the temperature rise of the resistor group can be suppressed compared to a configuration in which cooling is performed by a single cooling device. Furthermore, since a small cooling device can be used, the dimension in the thickness direction (axial direction of the cooling fan) can be reduced, which contributes to making the load testing device 1 more compact.

[0116] In particular, when a plurality of cooling devices are arranged in the direction in which the resistors extend (x direction), it becomes possible to configure a resistance unit using resistors that are long in the x direction.

[0117] In this embodiment, the multiple cooling devices that cool one resistance unit are described as being arranged in the direction in which the resistor extends (x direction), but in cases where the resistance unit is long in the vertical direction (y direction), the multiple cooling devices may also be arranged in the direction in which the resistors are arranged (y direction).

[0118] Furthermore, a configuration may be adopted in which a plurality of cooling devices are arranged in both the direction in which the resistors extend (x direction) and the direction in which the resistors are arranged (y direction), rather than in just one direction. Specifically, an example is conceivable in which four cooling devices are arranged in the x direction and three in the y direction, totaling 4 x 3 = 12 cooling devices, are arranged so as to face the opening of one holding portion of the resistance unit.

[0119] Furthermore, in this embodiment, the cooling device discharges cooling air in a horizontal direction. However, the cooling device may discharge cooling air in a vertical direction. In this case, the resistance unit to be cooled is disposed above a cooling section including a plurality of cooling devices.

[0120] Furthermore, a first exhaust port hood 35a may be provided at the exhaust port of the resistance unit 30, and a first intake port hood 55a may be provided at the intake port of the cooling section 50 (see FIG. 7).

[0121] The first exhaust port hood 35a has a first top surface portion 35a1 and a first side surface portion 35a2. The first exhaust port hood 35a protrudes in the z direction from the exhaust port of the resistance unit 30 and opens downward or obliquely downward.

[0122] The first intake port hood 55a has a second top surface portion 55a1 and a second side surface portion 55a2. The first intake port hood 55a protrudes in the z direction from within the intake of the cooling unit 50 and opens downward or obliquely downward.

[0123] The cooling section 50 draws in air from below or diagonally below through the first air intake hood 55a, and the drawn-in air is discharged downward or diagonally below through the resistance unit 30 and the first exhaust hood 35a.

[0124] The first exhaust port hood 35a may be configured to always remain protruding from the resistance unit 30 in the z-direction, or may be configured such that when not in use, the first upper surface portion 35a1 and the first side surface portion 35a2 are stored in the resistance unit 30, or at least a portion of the first upper surface portion 35a1 and the first side surface portion 35a2 are folded. In this case, when not in use, the first exhaust port hood 35a can be set to a state in which it does not protrude from the resistance unit 30 in the z direction.

[0125] The first exhaust port hood 35a may be opened and closed manually, or may be opened and closed electrically via an actuator (not shown). The first exhaust port hood 35a may be biased to be in a closed state and may be opened by the cooling air from the cooling unit 50. In this case, it becomes possible to automatically open and close the first exhaust port hood 35a without using electrical energy.

[0126] The first air intake hood 55a may be configured to always be maintained protruding from the cooling section 50 in the z-direction, or may be configured such that when not in use, the second upper surface portion 55a1 and the second side surface portion 55a2 are stored in the cooling section 50, or at least a portion of the second upper surface portion 55a1 and the second side surface portion 55a2 are folded. In this case, when not in use, the first intake port hood 55a can be set to a state where it does not protrude from the cooling part 50 in the z direction.

[0127] The first intake port hood 55a may be opened and closed manually, or may be opened and closed electrically via an actuator (not shown).

[0128] Furthermore, a roof portion 2e may be provided to cover the tops of the first housing 2a to the fourth housing 2d (see FIG. 8). The roof portion 2e has a shape with an inclined surface at the top, such as a hipped roof. This prevents rain and snow from directly hitting the tops of the first housing 2a to the fourth housing 2d when the load testing device 1 is installed outdoors. Also, even if snow accumulates on the roof 2e, it can be easily dropped down using the inclined surface.

[0129] Furthermore, a base 2f for supporting the first housing 2a to the fourth housing 2d may be provided at the bottom thereof. The electrical components contained in the first housing 2a to the fourth housing 2d are disposed at a higher position by the height of the base portion 2f. Therefore, even if the load testing device 1 is installed outdoors and snow accumulates around the load testing device 1, the possibility of snow or melted snow coming into contact with the electrical components that make up the load testing device 1 can be reduced.

[0130] A diffusion section 57 is provided between the cooling devices (first to sixth cooling devices 53a to 53f) of the cooling section 50 and the resistance units 30 (first to third resistance units 30a to 30c). The diffusion section 57 diffuses the cooling air emitted from the resistance units of the first to sixth cooling devices 53a to 53f in the xy directions (particularly the x direction), and is composed of, for example, a rod-shaped member extending in the y direction (see Figures 9 and 10). In this embodiment, the diffusion section 57 is configured by 12 rod-shaped members extending in the y direction, but the number of rod-shaped members is not limited to 12. Furthermore, the diffusion section 57 may be provided separately for each cooling device. However, the diffusion section 57 may be configured such that the xz cross section has a generally V-shape with a sharp point on the cooling section 50 side. By providing the diffusion section 57 between the cooling section 50 and the resistor unit 30, the cooling air can be diffused in the x direction, etc., and the cooling air can be brought into contact with the entire resistor almost uniformly.

[0131] Moreover, the diffusion section 57 may be configured with an opening / closing door that closes the exhaust ports of the cooling devices (first cooling device 53a to sixth cooling device 53f) of the cooling section 50 (see FIG. 11). In this case, when not in use, the diffusion section 57 is forced to close the exhaust ports of the cooling devices (first cooling device 53a to sixth cooling device 53f) of the cooling section 50, and when in use, the opening and closing door is pushed open by the cooling air, and the diffusion section 57 opens the exhaust ports of the cooling devices (first cooling device 53a to sixth cooling device 53f) of the cooling section 50. As a result, when not in use, no air flows through the resistance unit 30, making it difficult for dust and the like to enter from the outside.

[0132] It is desirable that the opening / closing door is provided with a stopper 57a that prevents the opening of the opening / closing door when the cooling devices (first cooling device 53a to sixth cooling device 53f) of the cooling section 50 are in the off state, and that releases this inhibited state when the cooling devices are in the on state (see Figure 11). The stopper 57a is controlled to be turned on and off in conjunction with the on and off states of the first cooling device 53a and the like. Specifically, when at least one of the first to sixth cooling devices 53a to 53f is turned on, the state in which the stopper 57a prevents the opening of the door is released, and the door opens due to the cooling air. Furthermore, when all of the first to sixth cooling devices 53a to 53f are turned off, after the doors are closed, the stoppers 57a prevent the doors from opening, and maintain the doors in a closed state. This prevents the door from being opened by wind when the cooling device is not in use.

[0133] In addition, a door that closes when biased and opens when negative pressure is applied by cooling air may be provided at the intake port of the cooling unit 50 in the same manner as the door. In this case, rather than providing an intake hood, the intake of the cooling unit 50 can be closed when not in use and opened when in use, without protruding from the cooling unit 50 in the z direction.

[0134] In addition, a door that closes when biased and opens when pushed by cooling air in the same manner as the door may be provided at the exhaust port of the resistance unit 30. In this case, rather than providing an exhaust port hood, the exhaust port of the resistor unit 30 can be closed when not in use and opened when in use, without protruding from the resistor unit 30 in the z direction.

[0135] Also, a configuration has been described in which the first insulator 33a connecting the first resistor unit 30a and the first housing 2a is attached to the lower part of the first holding portion 31a. Similarly, the second insulator 33b connecting the second resistor unit 30b and the first resistor unit 30a is attached to the lower part of the second holding portion 31b. Similarly, the third insulator 33c connecting the third resistor unit 30c and the second resistor unit 30b is attached to the lower part of the third holding portion 31c.

[0136] However, it is also possible to provide protrusions that protrude horizontally (x direction, z direction, etc.) from the top and bottom of the rectangular parallelepiped (holding part) that forms the outer shape of each resistance unit, and attach insulators between these protrusions (see Figures 9 and 10).

[0137] Specifically, a first upper protrusion 32a that protrudes in the x direction is provided on the upper portion of the first holding portion 31a. A second upper protrusion 32b protruding in the x direction is provided on the upper portion of the second holding portion 31b. A third upper protrusion 32c that protrudes in the x direction is provided on the upper portion of the third holding portion 31c. A first lower protrusion 32d that protrudes in the x direction is provided on the lower part of the first holding part 31a. A second lower protrusion 32e that protrudes in the x direction is provided on the lower part of the second holding part 31b. A third lower protrusion 32f protruding in the x direction is provided on the lower part of the third holding portion 31c.

[0138] First upper protrusion 32a to third upper protrusion 32c are generally L-shaped when viewed from the x direction, and have a first surface parallel to the xz plane and a second surface parallel to the xy plane extending downward in the y direction from the first surface. First to third lower protrusions 32d to 32f are generally L-shaped when viewed from the x direction, and have a third surface parallel to the xz plane, and a fourth surface parallel to the xy plane extending upward in the y direction from the third surface.

[0139] The first insulator 33a is attached between the third surface of the first lower protrusion 32d and the first housing 2a. The second insulator 33b is attached between the third surface of the second lower protrusion 32e and the first surface of the first upper protrusion 32a. The third insulator 33c is attached between the third surface of the third lower protrusion 32f and the first surface of the second upper protrusion 32b.

[0140] The insulator can be screwed in using the empty spaces below the upper protrusion and above the lower protrusion, making it easier to attach the insulator than in a configuration where the insulator is attached to the lower part of the holding part.

[0141] As shown in Figures 9 to 11, the upper protrusion and lower protrusion protruding in the x direction of one holding part may be separate bodies, or as shown in Figures 20 and 21, they may be configured as one body. When the portion corresponding to the upper protrusion and the portion corresponding to the lower protrusion are integrally formed, the first holding portion 31a is provided with a first protrusion region 32ad that protrudes in the x direction. The second holding portion 31b is provided with a second protruding region 32be that protrudes in the x direction. The third holding portion 31c is provided with a third protruding region 32cf that protrudes in the x direction.

[0142] The first protrusion region 32ad, the second protrusion region 32be, and the third protrusion region 32cf have an approximately U-shape (see FIG. 20) or an approximately rectangular shape (see FIG. 21) when viewed from the x direction, and have upper and lower surfaces parallel to the xz plane, and side surfaces connecting the upper and lower surfaces. The first insulator 33a is attached between the lower part (lower surface) of the first protruding region 32ad and the first housing 2a. The second insulator 33b is attached between the lower part (lower surface) of the second protruding region 32be and the upper part (upper surface) of the first protruding region 32ad. The third insulator 33c is attached between the lower part (lower surface) of the third protruding region 32cf and the upper part (upper surface) of the second protruding region 32be.

[0143] Since the portion corresponding to the upper protrusion and the portion corresponding to the lower protrusion are integrally formed as a protruding region, the strength of the portion where the insulator is attached can be increased compared to a configuration in which the upper protrusion and the lower protrusion are configured as separate bodies. In particular, when the protruding region is configured in a frame shape as shown in FIG. 21, the strength can be further increased compared to the configuration in which the protruding region is configured in a rod shape as shown in FIG.

[0144] Furthermore, a second exhaust port hood 35b may be provided at the exhaust port of the resistance unit 30, and a second intake port hood 55b may be provided at the intake port of the cooling section 50 (see FIG. 12).

[0145] The second exhaust port hood 35b has a first lower surface portion 35b1 and a third side surface portion 35b2. The second exhaust port hood 35b protrudes in the z direction from the exhaust port of the resistance unit 30 and opens upward or obliquely upward.

[0146] The second intake port hood 55b has a second lower surface portion 55b1 and a fourth side surface portion 55b2. The second intake port hood 55b protrudes in the z direction from within the intake of the cooling unit 50 and opens upward or obliquely upward.

[0147] The cooling section 50 draws in air from above or diagonally above through the second air intake hood 55b, and the drawn-in air is discharged upward or diagonally above through the resistance unit 30 and the second air exhaust hood 35b. In this case, the hot air discharged through the second exhaust port hood 35b is less likely to hit workers or the like who are near the second exhaust port hood 35b.

[0148] However, since there is a possibility that rain or snow may enter through the openings that open upward or diagonally upward, it is desirable to provide a roof portion 2e that covers the tops of the first housing 2a to fourth housing 2d, second exhaust port hood 35b, and second intake port hood 55b (see Figure 13).

[0149] Furthermore, in the configurations shown in Figures 1 to 13, a configuration has been described in which only one set of resistance unit 30, cooling section 50, and relay section 90 is provided, but a configuration in which multiple sets are provided and a load test is performed using multiple sets of resistance unit 30, cooling section 50, and relay section 90 using one control section 70 (see Figure 14).

[0150] FIG. 14 shows an example in which the load testing apparatus 1 includes a first resistor group G1 including a relay section 90 adjacent to the control section 70 in the x-direction, and a second resistor group G2 adjacent to the first resistor group G1 in the x-direction. In this case, it is desirable that at least an opening for passing a cable be provided on the surface of the first resistor group G1 in the first housing 2a and the second housing 2b that contacts the second resistor group G2. This makes it possible to assemble the load testing device 1 in a state where most of the cables are not visible outside the housing. Furthermore, a third resistor group (not shown) may be further provided adjacent to the second resistor group G2 in the x direction.

[0151] Each part of the control unit 70 (operation unit 71, control terminal unit 75, power supply control unit 77) is connected to the cooling fan of the first resistor group G1 and also to the cooling fan of the second resistor group G2.

[0152] The number of resistor groups provided in each of the resistor units 30 of the second resistor group G2 may be the same as the number of resistor groups provided in each of the resistor units 30 of the first resistor group G1, or may be less than the number of resistor groups provided in each of the resistor units 30 of the first resistor group G1.

[0153] That is, the number of switching devices (such as the first U-phase switching device SU1) of the relay section 90 in the first resistor group G1 that control the power supply to each resistor group of the first resistor unit 30a to the third resistor unit 30c in the first resistor group G1 is greater than the number of switching devices of the relay section 90 in the second resistor group G2 that control the power supply to each resistor group of the first resistor unit 30a to the third resistor unit 30c in the second resistor group G2.

[0154] In this case, when a load test with a small switching range of the load resistance value is performed, the first resistor group G1 is mainly used, when a load test with a large switching range of the load resistance value is performed, the second resistor group G2 is mainly used, and when a load test with a large load resistance value is performed, both the first resistor group G1 and the second resistor group G2 are used. This makes it possible to perform a load test with a large load while sharing the control unit 70, compared to a configuration in which only the first resistor group G1 is provided.

[0155] When there is one resistor group provided in each resistor unit 30 of the second resistor group G2, a relay unit 90 is not provided in the second resistor group G2, and the power supply control unit 77 of the control unit 70 is connected to the resistor group provided in each resistor unit 30 of the second resistor group G2 via a VCS (vacuum contact switch) without going through the relay unit 90 (see Figures 15 and 17). FIG. 16 shows the connection relationship between the first resistor group G1 and the control unit 70 in the load testing device 1, and omits details of the second resistor group G2. FIG. 17 shows the connection relationship between the second resistor group G2 and the control unit 70 in the load testing device 1, and omits details of the first resistor group G1. The VCS may be provided in the resistor unit 30 of the second resistor group G2, or in the control unit .

[0156] Furthermore, a hood (narrowed portion 58) with a narrowed structure may be provided between the cooling portion 50 and the resistance unit 30 to concentrate the cooling air on the portion of the resistance unit 30 where the resistors are located (see FIG. 18).

[0157] The narrowed portion 58 has a generally quadrangular pyramidal shape with a wide lower base (lower base opening) on ​​the cooling portion 50 side and a narrow upper base (upper base opening) on ​​the resistance unit 30 side, and both the lower and upper bases are open. The upper base of the lower narrowed portion 58 is disposed inside the first holding portion 31a without contacting the first holding portion 31a. The upper base of the middle narrowed portion 58 is disposed inside the second holding portion 31b without contacting the second holding portion 31b. The upper base of the upper narrowed portion 58 is disposed inside the third holding portion 31c without contacting the third holding portion 31c. By providing the narrowed portion 58, it becomes possible to concentrate the cooling air from the cooling portion 50 inside the first holding portion 31a to the third holding portion 31c.

[0158] The narrowed portion 58 may further be provided with a diffusing portion 57 (see FIG. 19). FIG. 19 shows an example in which a rod-shaped diffusing portion 57 is provided at the upper bottom opening of a narrowed portion 58.

[0159] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as the inventions described in the claims and their equivalents. [Explanation of symbols]

[0160] 1 Load test equipment 1a~1c 1st load test section ~ 3rd load test section 2a First housing (resistor unit housing) 2a1 1st opening 2b Second housing (cooling unit housing) 2b1 2nd opening 2c Third housing (control unit housing) 2d Fourth housing (relay housing) 2e Roof 2F base 3 Connecting members 4 Control wire 30 Resistor Units 30a to 30c First resistance unit to third resistance unit 31a~31c 1st holding part~3rd holding part 31a1~31c1 1st opening~3rd opening 32a~32c 1st upper protrusion ~ 3rd upper protrusion 32d~32f 1st lower protrusion ~ 3rd lower protrusion 32ad 1st protruding area 32be 2nd protruding area 32cf 3rd protrusion area 33a~33c 1st insulator~3rd insulator 35a First exhaust hood 35a1 1st top section 35a2 1st side part 35b Second exhaust hood 35b1 1st bottom part 35b2 3rd side part 50 Cooling section 50a~50c 1st cooling section~3rd cooling section 53a~53f 1st cooling device~6th cooling device 55a Hood for first intake 55a1 2nd top part 55a2 2nd side part 55b Second intake hood 55b1 2nd bottom part 55b2 Fourth side part 57 Diffusion section 57a Stopper 58 Stenosis 70 Control Unit 71 Operation section 73 Power terminal section 75 Control terminal section 77 Power supply control unit 90 Relay Section FS Fan Switch G1 First Resistance Group G2 Second Resistance Group MS mode switch RU1~RU3 1st U phase resistor group ~ 3rd U phase resistor group RV1~RV3 1st V phase resistor group ~ 3rd V phase resistor group RW1~RW3 1st W phase resistor group ~ 3rd W phase resistor group S1~S3 1st operation switch~3rd operation switch SU1 to SU3: 1st U-phase switching device to 3rd U-phase switching device SV1~SV3 1st V-phase switching device~3rd V-phase switching device SW1 to SW3: 1st W-phase switching device to 3rd W-phase switching device UT U phase terminal VT V phase terminal WT W phase terminal

Claims

[Claim 1] the first resistor unit having a plurality of first resistors; a first cooling unit including a cooling device that sends cooling air to the plurality of first resistors; Equipped with A load testing device in which a diffusion section for diffusing cooling air is provided between the first cooling section and the first resistance unit, and the diffusion section is composed of an opening / closing door that closes the exhaust port of the first cooling section when biased, and the opening / closing door is opened by the cooling air discharged from the first cooling section, or an exhaust port hood is provided at the exhaust port of the first resistance unit, and the exhaust port hood is biased to a closed state and opened by the cooling air from the first cooling section.

Images