WO2021110914A1

WO2021110914A1 - Hydraulic device for testing electromagnetic compatibility and/or other characteristics of an electric motor

Info

Publication number: WO2021110914A1
Application number: PCT/EP2020/084630
Authority: WO
Inventors: Shinichiro Nishizawa
Original assignee: TDK Europe GmbH
Priority date: 2019-12-06
Filing date: 2020-12-04
Publication date: 2021-06-10
Also published as: DE102019133393A1

Abstract

A hydraulic device for testing electromagnetic compatibility and/or other characteristics of an electric motor (2) comprises a hydraulic unit (3) for mechanical coupling to the electric motor under test (2), a fluid tank (8) for holding a hydraulic fluid (9), fluid pipelines (6, 7) connecting the fluid tank (8) with the hydraulic unit (3), an electric motor (14) for driving pumping the hydraulic fluid (9) through the fluid pipelines (6, 7) and a shielding device (15) for electromagnetic shielding of the electric motor (14) which is configured for driving pumping, such that the hydraulic device (1) is arrangeable in an electromagnetic shielding room (16) together with the electric motor under test (2) without electromagnetic interference by the electric motor (14) which is configured for driving pumping.

Description

Hydraulic device for testing electromagnetic compatibility and/or other characteristics of an electric motor

The present invention relates to a hydraulic device for testing electromagnetic compatibility (EMC) of an electric motor. The device may be also suitable for testing other characteristics of an electric motor, such as acoustic or electric characteristics. The electric motor may be an electric drive for an automobile or bicycle, for example. The electric motor may be alternatively used in consumer or industrial applications.

The electromagnetic compatibility of electric motors is a key issue of their proper functionality and also regulated by legal provisions. EMC testing ensures that the electric device does not generate or is not affected by electromagnetic disturbance.

For EMC testing or measuring other characteristics, the electric motor may be coupled to a test load and/or a test drive which simulates a load and/or a drive according to the intended use of the electric motor. The test load and/or test drive may comprise electric components producing electromagnetic radiation which may disturb the testing environment or which may be disturbed by outside electromagnetic radiation.

German utility model DE 202016 008 598 U1 discloses a facility for testing electric drives, in which a hydraulic unit working as a pump or a motor is used. The hydraulic unit is connected to the electric motor under test. By using the hydraulic unit, disturbing electromagnetic radiation is reduced which occurs when an electric motor is directly connected to the electric motor under test. The hydraulic unit is positioned in an EMC chamber together with the electric motor under test and is coupled via fluid pipelines to an electric motor positioned outside the EMC chamber.

German patent application DE 4120 665 A discloses a compact hydraulic pump driven by an electric motor, the pump having a compact size. Furthermore, compact hydraulic motors are known for driving lifting platforms, for example.

It is an object of the present invention to provide an improved hydraulic device for testing electromagnetic compatibility of an electric motor.

In one aspect, the present invention relates to a hydraulic device for testing electromagnetic compatibility of an electric motor. In particular, the hydraulic device may simulate a load and/or a drive for the electric motor under test. The hydraulic device may also be suitable for testing other characteristics of the motor under test, such as acoustic and electric characteristics.

The hydraulic device comprises a hydraulic unit for being mechanically coupled to the motor under test. The hydraulic unit may be operable as a hydraulic pump and/or a hydraulic motor. The hydraulic unit may be coupled to the shaft of the electric motor. The coupling may be directly or indirectly.

As an example, a shaft of the hydraulic unit may be directly coupled to a shaft of the electric motor. As a further example, a shaft of the hydraulic unit may be coupled to a shaft of the electric motor by a coupling device. The coupling device may comprise a roller conveyer, for example.

The hydraulic device may comprise a fluid tank for holding a hydraulic fluid. The fluid tank is connected by fluid pipelines to the hydraulic unit. The hydraulic device thus comprises a closed fluid loop leading from the fluid tank via one of the fluid pipelines to the hydraulic unit and back to the fluid tank via another one of the fluid pipelines.

The hydraulic device comprises an electric motor for simulating a recuperation mode of the electric motor under test. The electric motor may drive a further hydraulic unit for conveying the fluid in the fluid pipeline, thereby driving the hydraulic unit and the electric motor under test.

The hydraulic device may comprise further electric components, such as control and communication devices for controlling the operation of the electric motor or other parts of the hydraulic device and electric cables.

The hydraulic device comprises a shielding device for electromagnetic shielding of the electric motor which is configured for driving pumping. The shielding device may also shield other electric components of the hydraulic device. The shielding device is configured to shield the electric motor and optionally other components such that the electric motor does not electromagnetically interfere during the measurements. In particular, disturbing emission, e.g. conducted or radiated emission, of these electric components is avoided and the immunity of these electric components is ensured. In particular, the shielding refers to electromagnetic high frequency noises. The hydraulic device may be positioned together with the electric motor in an electromagnetic (EMC) chamber in which the measurements are conducted. Alternatively, the hydraulic device may be positioned in the vicinity of the electric motor during open area measurements.

As an example, at least some of the electric components may be located in a shield box, such as a metal box. The hydraulic unit may be located outside the metal box. In some embodiments, the hydraulic unit may be located inside the shield box.

In an embodiment, the fluid tank comprises metal and the electric motor is at least partially located inside the fluid tank such that the shielding device is at least partially provided by the fluid tank.

In a first mode of operation, the hydraulic unit may be operated as a hydraulic pump driven by the electric motor under test. Accordingly, the electric motor under test is connected to a load.

In a second mode of operation, the hydraulic unit may be operated as a hydraulic motor. The electric motor may drive a further hydraulic unit which pressurizes and circulates the fluid in the fluid pipeline and, thereby, drives the hydraulic unit which transforms the fluidic pressure and movement in a mechanical movement such as a rotation of a shaft. The second mode of operation may be used for testing EMC or other characteristics during recuperation, i.e., recovery of electrical energy from mechanical energy. The hydraulic device may have a compact size such that the hydraulic device is portable and/or arrangeable in an electromagnetic shielding room (EMC chamber) together with the electric motor under test. In particular, the hydraulic device may have dimensions not larger than 200 cm x 150 cm x 150 cm.

The oil tank may have a capacity not larger than 501. Depending on the required power output, the oil tank may have also a smaller capacity, such as 21, for example. The power output of the hydraulic device may be in the range of 0.1 to 200 kW. As an example, the hydraulic device may be suitable for testing electric motors having an output of electric power of 10 to 100 kW.

The compact size of the hydraulic device enables using the device in different environments. The hydraulic device may be portable such that it can be easily transported from one facility to another facility and may also be used in open area measurements. In some embodiments, the hydraulic device may be transportable by taking the whole device with both hands. Accordingly, the parts of the hydraulic device may be firmly connected and close to each other.

The hydraulic device may comprise an outer housing. The fluid tank and the electric motor may be located in the outer housing. The outer housing may also function as a shielding device for electromagnetic shielding of the electric motor and other electric components of the hydraulic device.

In some embodiments, the hydraulic unit and/or the fluid pipelines may be located within the outer housing. In other embodiments, the hydraulic unit may be located outside the outer housing.

The hydraulic device including the fluid tank, pipelines and the hydraulic unit may be arrangeable in the EMC chamber together with the electric motor under test. In this case, the fluid pipelines have not to be led from outside into the EMC chamber. This has the advantage that the disturbance by providing a lead-through into the EMC chamber is avoided. In addition to that, handling of the device is easier because short hydraulic pipelines can be used. Furthermore, large EMC testing facilities are not required, allowing space and costs to be saved.

The electric motor for driving pumping may be connectable to a power supply. The power supply may be part of the hydraulic device or may be separate from the hydraulic device. The power supply may be a battery, e.g. a mobile battery pack. In other embodiments, the power supply may be a generator or a standard network power supply for electrical power mode AC and DC.

In some embodiments, the power supply may also be located in the outer housing of the device. In other embodiments, the power supply may be located outside the outer housing and power supply lines may be led into the housing. The power supply lines may be electromagnetically shielded.

The hydraulic device including the fluid tank, the fluid pipelines and the hydraulic unit may be arrangeable on a rotary table together with the electric motor under test. During EMC testing, the electric motor may be rotated such that EMC testing can be done from all sides with a static testing device. Positioning the hydraulic device on the rotary table makes the handling of the testing assembly much easier as a rotation of the rotary table is not hampered by the fluid pipelines. Alternatively, the hydraulic device may be placed under the rotary table, for example.

According to a further aspect, an assembly for testing EMC and/or other characteristics of an electric motor is disclosed. The assembly may comprise the hydraulic device as described in the foregoing and further comprises the electric motor under test coupled to the hydraulic device, in particular to a hydraulic unit of the device. The electric motor may be coupled directly or indirectly to the hydraulic unit.

The assembly may further comprise a rotary table and/or rotary floor, wherein the electric motor under test and at least some components of the hydraulic device are positioned on the rotary table and/or rotary floor. In an alternative embodiment, the electric motor may be positioned on the rotary table and/or rotary floor and at least some components of the hydraulic device may be positioned under the rotary table and/or rotary floor. The rotary table may be positioned in an EMC chamber. The rotary floor may be the floor of the EMC chamber. Some components of the hydraulic device may be located under a storage area of the rotary floor and, thus, outside the EMC chamber.

According to a further aspect, an assembly for testing electromagnetic compatibility and/or other characteristics of an electric motor under test is disclosed. The assembly comprises a hydraulic device and the electric motor under test coupled to the hydraulic device. The assembly comprises a rotary floor on which parts of the hydraulic device and the electric motor under test are positioned. Further components of the hydraulic device and/or a power supply for the hydraulic device may be located in a storing area below the rotary floor. The hydraulic device may be the device described in the foregoing.

According to a further aspect, a use of a hydraulic device for EMC testing and/or testing other characteristics of an electric motor is disclosed. In particular, the hydraulic device is used for simulating a load and/or a drive for testing characteristics of an electric motor. The hydraulic device may be the device as described in the foregoing.

In this use, the hydraulic device may be located in an EMC chamber together with the electric motor under test.

Alternatively, the hydraulic device may be used in an open area measurement, such that the electric motor under test and the hydraulic device are not located in an EMC chamber.

According to a further aspect, a method for testing electromagnetic compatibility and/or other characteristics of an electric motor is disclosed. The method comprises the steps of providing a hydraulic device and coupling the hydraulic device to the electric motor under test. The hydraulic device may be the device described in the foregoing .

At least parts of the hydraulic device and the electric motor under test may be positioned on a rotary table and/or a rotary floor, wherein the rotary table is rotated during measurements . The present disclosure comprises several aspects of an invention. Every feature described with respect to one of the aspects is also disclosed herein with respect to the other aspect, even if the respective feature is not explicitly mentioned in the context of the specific aspect.

Further features, refinements and expediencies become apparent from the following description of the exemplary embodiments in connection with the figures.

Figure 1 schematically shows a hydraulic device connected to an electric motor under test,

Figure 2 schematically shows an assembly for EMC testing according to an embodiment,

Figure 3 schematically shows an assembly for EMC testing according to a further embodiment,

Figure 4 schematically shows an assembly for EMC testing according to a further embodiment,

Figure 5 schematically shows an assembly for EMC testing according to a further embodiment,

Figure 6 schematically shows a further embodiments of a hydraulic device connected to an electric motor under test,

Figure 7 schematically shows a further embodiments of a hydraulic device connected to an electric motor under test. In the figures, elements of the same structure and/or functionality may be referenced by the same reference numerals. It is to be understood that the embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale.

Figure 1 shows a hydraulic device 1 connected to an electric motor under test 2 for testing electromagnetic compatibility (EMC) of the electric motor under test 2. As an example, EMC testing may be in accordance with Automotive Electromagnetic Compatibility standard CISPR 25. The hydraulic device 1 may also be suitable for testing other motor characteristics of the electric motor under test 2. A motor is also denoted by "M" in the figure. As examples, acoustic or driving characteristics such as engine speed or current-voltage functions may be tested.

The hydraulic device 1 may simulate a load for the electric motor under test 2. Additionally or alternatively, the hydraulic device 1 may simulate a drive for the electric motor under test 2 for simulating a recuperation operational mode. The hydraulic device 1 may be configured to be switchable between the two modes.

The hydraulic device 1 comprises a hydraulic unit 3 working as a pump and/or a motor, depending on the operational mode. The hydraulic unit 3 is connected to the electric motor under test 2, in particular to a shaft 5 of the electric motor under test 2. The hydraulic device 1 may comprise a coupling device 4, in which the shaft 5 of the electric motor 2 can be plugged-in, for example. The electric motor under test 2 may be used as an electric drive for an automobile or a bicycle, for example. The electric motor under test 2 may alternatively be used as an electric drive for industrial or consumer applications. The electric motor under test 2 may be suitable for delivering 10 to 100 kW of electric power.

The hydraulic device 1 comprises fluid pipelines 6, 7 being connected with a fluid tank 8. The fluid tank 8 may contain a hydraulic fluid 9 such as oil or water. The hydraulic fluid 9 is conveyed in the fluid pipelines 6, 7 from and into the fluid tank 8 in a closed loop.

In a first operational mode, the hydraulic unit 3 functions as a pump driven by the electric motor under test 2. The hydraulic unit 3 thus transforms a mechanical movement provided by the electric motor under test 2 into a conveyance of the hydraulic fluid 9 in the fluid pipelines 6, 7, in the direction of the arrows, for example.

The amount of hydraulic energy can be controlled by a control valve 10. A pressure relief valve 11 controls overpressure in the system. Further auxiliary equipment 12 may be present such as a line filter selecting out dust and particles in the system or a heat exchanger, for example.

The hydraulic device 1 comprises a second hydraulic unit 13 functioning as a pump. The second hydraulic unit 13 is driven by a further electric motor 14. The further electric motor 14 may include electronic, in particular power electronic, for controlling the motor functions. In the first operational mode, the second hydraulic unit 13 serves to maintain a pre- defined pressure of the hydraulic fluid 9 such that cavitations in the hydraulic fluid 9 are prevented.

In a second operational mode, the hydraulic device 1 functions as a drive for the electric motor under test 2.

This mode allows testing the electric motor 2 in recuperation, i.e., recovery of electric energy from mechanical energy. The hydraulic fluid 9 is pressurized and conveyed by the further hydraulic unit 13 driven by the electric motor 14. The conveyance and pressure of the hydraulic fluid 9 is converted into mechanical motion by the hydraulic unit 3, which drives the electric motor under test 2.

The hydraulic device 1 may comprise further auxiliary equipment such as a further pump and pump motor for facilitating conveyance of the fluid from the tank 8 into the fluid pipelines 6, 7. This may be particularly useful when the hydraulic device 1 is configured to be operated in both directions, i.e., in the first and second operational mode.

The hydraulic device 1 may further comprise electronic control facilities (not depicted) and a power supply 20 (also denoted by AC/DC in the Figure) for supplying electric power to the electric motor 14. The power supply 20 may be integrated in the hydraulic device 1. The power supply 20 and supply lines 27 leading from the power supply 20 to the electric motor 14 may be located within an outer housing 25 and/or within the shield box 15. In this case, the hydraulic device 1 may be free from electric cables leading to the outside. In other embodiments, the power supply 20 may be located outside an outer housing 25 and may be separate from the hydraulic device 1. The supply lines 27 may lead through an outer housing 25 to the outside. In this case, an additional shielding device may be provided for shielding the supply lines 27 and/or the power supply 20.

The power supply 20 may be a battery, e.g. a mobile battery pack. In other embodiments, the power supply may be a generator or a standard network power supply for electrical power mode AC and DC. The power supply 20 may have low and high voltage of 6 V to 2000 V, for example.

The hydraulic device 1 may be compact. In particular, the hydraulic device 1 may have dimensions not larger than 200 cm x 200 cm x 200 cm. In particular, the hydraulic device 1 may have dimensions not larger than 200 cm x 150 cm x 150 cm. The oil tank may have a capacity not larger than 5001. In particular, the oil tank may have a capacity not larger than 50 1. Depending on the required power output, the oil tank may have a smaller capacity, such as 21, for example.

The hydraulic device 1 may comprise an outer housing 25. The components of the hydraulic device 1 shown in Figure 1, in particular the hydraulic unit 3, the electric motor 14, the further hydraulic unit 13, the fluid tank 8, the fluid pipelines 6, 7, the valves 11, 12 and the auxiliary equipment 12 may be located in the outer housing 25. In this case, the hydraulic device 1 may be easily portable by gripping the outer housing 25. In a further embodiment, the fluid pipelines 6, 7 and the hydraulic unit 3 may not be fully located in the outer housing 25. This may enable positioning the hydraulic device 1 more flexible. The outer housing 25 may comprise a metal. The outer housing 25 may have a shielding function such that it shields the electric motor 14 and further electric components. This enables positioning the hydraulic device 1 including the electric motor 14 and further electric components in vicinity to the electric motor under test 2 without that the electric components of the hydraulic device 1 interfere with the measurements .

The electric motor 14 and other electric components of the device 1 may be positioned in an shield box 15, in particular a metallic shield box 15, in order to achieve electromagnetic shielding and avoid interference with the EMC measurements of the electric motor under test 2. In a specific embodiment, the fluid tank 8 may be metallic and the electric motor 14 and other electric components of the hydraulic device 1 may be at least partially located in the fluid tank 8, serving as a shield box 15.

Accordingly, the outer housing 25, the shield box 15 or the fluid tank 8 may serve as a shielding device 26, for example.

When the fluid pipelines 6, 7 are located in the outer housing 25, the fluid pipelines 6, 7 may have an overall length of 0.2 to 2 meter, for example. In case that the fluid pipelines 6, 7 are positioned outside the outer housing 25, they may have an overall length of more than 2 meter.

The hydraulic device 1 together with the electric motor under test 2 may be located in an electromagnetic shielding room (EMC chamber) 16 and thus being shielded from outside electromagnetic radiation, in particular against high frequency electromagnetic radiation, or may be used in open area measurements. This is possible due to the compact size of the hydraulic device 1 and due to the shielding device 26 ensuring that the electric components of the hydraulic device 1 do not interfere with the measurements.

The electric motor under test 2 may be positioned on a rotary table, such that testing the electromagnetic compatibility is enabled from all sides with a static testing equipment. Due to the small dimensions, the hydraulic device 1 may be positioned on the rotary table.

Figure 2 shows an assembly 17 and a method for EMC testing comprising a hydraulic device 1 and an electric motor under test 2. The assembly may be suitable for testing other characteristics of the electric motor under test 2. The hydraulic device 1 may be the hydraulic device 1 described in connection with the hydraulic device 1 of Figure 1, for example.

The electric motor under test 2 is coupled to the hydraulic device 1, in particular to the hydraulic unit (see Figure 1). The coupling may be directly by the shaft 5 of the electric motor under test 2 being plugged into a coupling device of the hydraulic device 1. As a further example, a shaft of the hydraulic device leading out of the outer housing 25 of the hydraulic device may be connected to the shaft 5 of the electric motor.

In the depicted embodiment, the power supply 20 is located outside of the outer housing 25 of the hydraulic device and is connected by power supply lines 27, which lead to the electric motor 14 for driving pumping located inside the outer housing 25. The power supply lines 27 are shielded by an EMC filter, for example, such that no interference is created with the measurements.

In a further embodiment, the power supply 20 and the power supply lines 27 are located inside the outer housing 25.

Both the hydraulic device 1 and the electric motor under test 2 are positioned on a rotary table 18 which rotates during EMC testing. The rotational movement is denoted by "w" in the figure. A static EMC testing equipment 19 emitting and/or receiving electromagnetic radiation is located at a fixed position .

The assembly 17 may be located within an EMC chamber 16. Alternatively, the assembly 17 may be used without an EMC chamber 16, i.e., for open area EMC testing.

Figure 3 shows a further assembly 17 and a method for EMC testing comprising a hydraulic device 1 and an electric motor under test 2. In the following, only the main differences to the embodiment of Figure 2 are described.

The hydraulic device 1 and the electric motor under test2 are located on a rotary floor 18 of the EMC chamber 16. The rotary floor is configured to rotate during the measurements. The power supply 20 is located in a storage area 22 under the rotary floor 18. The storage area 22 is outside the EMC chamber 16. The power supply lines 27 are led from the storage area 22 into the EMC chamber 16. The power supply lines 27 are electromagnetically shielded. In further embodiments, the power supply 20 may be located outside a side wall of the EMC chamber 16 and the power supply lines 27 may be led through the wall. The power supply 20 may be also integrated in the hydraulic device 1 as shown in Figure 1.

The motor 2 is positioned on a mounting device 23 which holds the motor 2 firmly in place. The motor 2 and the mounting device 23 are located on the hydraulic device 1. Accordingly, the outer housing 25 of the hydraulic device 1 provides a suitable surface for locating the motor 2 and the mounting device 23. In an embodiment, the mounting device 23 may be integrated in the hydraulic device, in particular in the outer housing 25.

Figure 4 shows a further assembly 17 and a method for EMC testing comprising a hydraulic device 1 and an electric motor under test 2. In the following, only the main difference to the foregoing embodiments are described.

The hydraulic unit 3 (also denoted by "H" in the figure) is located outside an outer housing 25 of the hydraulic device 1. The fluid pipelines lead 6, 7 lead out of the outer housing 25 to the hydraulic unit 3. Other components of the hydraulic device 1 such as the electric motor for driving pumping and the further hydraulic unit are positioned on a floor of the EMC chamber 26. The components are located within the outer housing 25. The power supply 20 is positioned in a storage area 22 under the rotating floor 18 and power supply lines 27 connect the power supply 20 to the electric motor for driving pumping in the outer housing 25.

Each of the hydraulic unit 3 and the motor under test 2 are positioned by a mounting device 23 on a test table 24 on the rotatory floor 21. Figure 5 shows a further assembly 17 and a method for EMC testing comprising a hydraulic device 1 and an electric motor under test 2. In the following, only the main difference to the foregoing embodiments are described.

The hydraulic unit 3 and the motor 2 are positioned on a test table 24 and held by a single mounting device 23. The test table 24 is positioned on a rotary floor 21.

Other components of the hydraulic device 1 such as the electric motor for driving pumping and the further hydraulic unit are located in a storage area 22 below the rotating floor 21. These components are located in an outer housing 25, for example. Also the power supply 20 and the power supply lines 27 are located in the storage area 22. Fluid pipelines 6, 7 lead through the rotary floor 21 to the hydraulic unit 3.

Figure 6 shows a further embodiment of a hydraulic device 1 connected to an electric motor under test 2. The hydraulic device 1 is configured such that, in a recuperation mode, energy is fed back into a power grid 28. The power grid 28 may be a standard network power supply.

As in the foregoing embodiments, the device 1 may be switchable between a first mode in which the hydraulic device 1 simulates a load for the electric motor under test 2 and a second mode, i.e., the recuperation mode, in which the electric motor under test 2 simulates a load for the hydraulic device 1.

As shown in Figure 6, the electric motor under test 2 is connected via an inverter 29, such as a pulse inverter, to the power grid 28. Accordingly, mechanical energy is converted into electrical energy. Thereby, energy is deduced from the hydraulic device 1 such that overheating of the device can be prevented. In this case, a heat exchanger or other additional cooling facilities may not be required. The inverter 29 may be positioned inside or outside the EMC chamber 16.

Figure 7 shows a further embodiment of a hydraulic device 1 connected to an electric motor under test 2.

In difference from Figure 6, the hydraulic device 1 is configured such that, in a recuperation mode, energy is deduced from the hydraulic device 1 by heating of an ohmic resistance 30 outside the hydraulic device 1. The power grid 28 may only be used for supplying power for driving the electric motor under test 2 in the first operational mode, for example. The ohmic resistance 30 and the inverter 29 may be positioned inside the EMC chamber 16.

In all embodiments, the power grid 28 may be replaced by a battery, e.g. a mobile battery pack. Also in this case, a recuperation mode, in which the battery is recharged, is possible. The battery pack may be positioned within the EMC chamber 16 or in a storage area below the EMC chamber 16, for example.

Furthermore, also the power supply of the electric motor 14 of the hydraulic device 1 may be configured such that mechanical energy is converted into electrical energy and fed back in the power supply. This may be the case, when the hydraulic device 1 is driven in the first operational mode, i.e., when the electric motor 14 acts as a load for the electric motor under teste 2. Also in this case, energy may be deduced by providing an ohmic resistance.

Reference numerals

1 hydraulic device

2 electric motor under test

3 hydraulic unit

4 coupling device

5 shaft

6 fluid pipeline

7 fluid pipeline

8 fluid tank

9 hydraulic fluid

10 control valve

11 pressure relief valve

12 auxiliary equipment

13 further hydraulic unit

14 electric motor for driving pumping

15 shield box

16 electromagnetic shielding room

17 assemb1y

18 rotary table

19 EMC testing equipment

20 electrical power supply

21 rotary floor

22 storage area

23 mounting device

24 test table

25 outer housing

26 shielding device

27 power supply lines

28 power grid

29 inverter

30 resistance

Claims

1. A hydraulic device for testing electromagnetic compatibility and/or other characteristics of an electric motor, the hydraulic device (1) comprising a hydraulic unit (3) for mechanical coupling to an electric motor under test (2), a fluid tank (8) for holding a hydraulic fluid (9), fluid pipelines (6, 7) connecting the fluid tank (8) with the hydraulic unit (3), an electric motor (14) for driving pumping the hydraulic fluid (9) through the fluid pipelines (6, 7) and a shielding device (15) for electromagnetic shielding of the electric motor (14) which is configured for driving pumping, such that the hydraulic device (1) is arrangeable in an electromagnetic shielding room (16) together with the electric motor under test (2).

2. The hydraulic device of claim 1, having outer dimensions not larger than 200 cm x 200 cm x 200 cm.

3. The hydraulic device of any of claims 1 or 2, wherein the electric motor (14) for driving pumping is configured for simulating a recuperation operational mode of the electric motor under test (2).

4. The hydraulic device of claim 3, being switchable between a first operational mode, in which the hydraulic unit (3) is operated as a hydraulic pump driven by the electric motor under test (2), and the recuperation operational mode.

5. The hydraulic device of any of claims 3 or 4, being configured such that, in the recuperation mode, energy is fed back into a power supply (28) for the electric motor under test (2).

6. The hydraulic device of any of claims 3 to 5, being configured such that, in the recuperation mode, energy is deduced into a ohmic resistance (30) located outside an outer housing (25) of the hydraulic device (1).

7. The hydraulic device of any of the preceding claims, comprising an outer housing (25) and a power supply (20), wherein the power supply (20) and the electric motor (14) are located in the outer housing (25).

8. The hydraulic device of any of the preceding claims, comprising an outer housing (25), wherein the fluid pipelines (6, 7) are located within the outer housing (25).

9. The hydraulic device of any of the preceding claims, comprising an outer housing (25), wherein the fluid pipelines (6, 7) are located outside the outer housing (25) and are visible from the outside.

10. The hydraulic device of any of the preceding claims, wherein the fluid tank (8) comprises metal, wherein the electric motor (14) for driving pumping is at least partially located inside the fluid tank (8) such that the shielding device (15) is at least partially provided by the fluid tank (8).

11. An assembly for testing electromagnetic compatibility and/or other characteristics of an electric motor, the assembly (17) comprising the hydraulic device (1) of any of claims 1 to 10 and the electric motor under test (2) coupled to the hydraulic unit (3).

12. The assembly of claim 11, comprising a rotary table (18) and/or a rotary floor (21), wherein at least parts of the hydraulic device (1) and the electric motor under test (2) are positioned on the rotary table (18) and/or the rotary floor (21).

13. A use of the hydraulic device of any of claims 1 to 10 for simulating a load and/or a drive for testing electromagnetic compatibility and/or measuring further characteristics of an electric motor under test (2).

14. The use according to claim 13, wherein the hydraulic device (1) and the electric motor under test (2) are located in an electromagnetic shielding room (16).

15. The use according to claim 13 for testing electromagnetic compatibility and/or measuring further characteristics of the electric motor under test (2) in an open area test site.

16. A method for testing electromagnetic compatibility and/or other characteristics of an electric motor, comprising the steps of providing the hydraulic device of any of claims 1 to 10 and coupling the hydraulic device (1) to the electric motor under test (2).

17. The method of claim 16, comprising the step of positioning at least parts of the hydraulic device (1) and the electric motor under test (2) on a rotary table (18) and/or a rotary floor (21) and rotating the rotary table (18) and/or rotary floor (21).

18. An assembly for testing electromagnetic compatibility and/or other characteristics of an electric motor under test, the assembly (17) comprising a hydraulic device (1) and the electric motor under test (2) coupled to the hydraulic device (1) and a rotary floor (21) on which the electric motor under test (2) and at least parts of the hydraulic device (1) are positioned, wherein further components of the hydraulic device (1) and/or a power supply (20) for the hydraulic device (1) are located in a storage area (22) below the rotary floor (21).