Frequency converter assembly and frequency converter unit

FIELD OF THE INVENTION

The present invention relates to a frequency converter assembly and to a frequency converter unit.

A known frequency converter unit comprises cable terminals for power supply cabling and load cabling on a front side wall thereof. The known frequency converter unit is adapted to be installed in a frame having power supply cabling and load cabling on a front wall thereof. The power supply cabling is fixedly connected to the cable terminals for power supply cabling on the front side wall of the known frequency converter unit. Similarly, the load cabling is fixedly connected to the cable terminals for load cabling on the front side wall of the known frequency converter unit.

One of the problems associated with the above described known frequency converter unit is that there are considerable difficulties in installing the known frequency converter unit in a frame having the power supply cabling and load cabling on a side wall thereof or on a back wall thereof.

BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention is to provide a frequency converter unit which can easily be installed in a frame having the power supply cabling and load cabling on a side wall thereof. The objects of the invention are achieved by a frequency converter assembly and a frequency converter unit which are characterized by what is stated in the independent claims. The preferred embodiments of the invention are disclosed in the dependent claims.

The invention is based on the idea of providing a frequency converter unit with input side bus bars which are spaced apart in a first direction, and with output side bus bars which are spaced apart in the first direction, the first direction being perpendicular to installation direction of the frequency converter unit.

An advantage of the frequency converter unit of the invention is that the frequency converter unit may be installed in several different positions, wherein a power supply cabling and load cabling may be provided on different sides of a frame in which the frequency converter unit is installed.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be described in greater detail by means of preferred embodiments with reference to the attached drawings, in which

• Figures 1 a and 1 b show axonometric views of a frequency converter unit according to an embodiment of the invention;
• Figures 2a ― 2d show side views of the frequency converter unit of Figure 1;
• Figures 3a and 3b show axonometric views of a frequency converter assembly according to an embodiment of the invention and comprising the frequency converter unit of Figure 1; and
• Figures 4a and 4b show axonometric views of a frequency converter assembly according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Figures 1 a and 1 b show axonometric views of a frequency converter unit 4 according to an embodiment of the invention. Figure 1 a shows that the frequency converter unit 4 comprises a unit body 40, input bus bar means 41 and output bus bar means 42. The input bus bar means 41 have a plurality of input side bus bars 41 a, 41 b, 41 c, 41 d, 41 e protruding from the unit body 40. The input side bus bars 41 a, 41 b and 41 c are adapted to be connected to corresponding phase conductors of a three-phase power supply. The input side bus bars 41 d and 41 e are connected to a direct voltage intermediate circuit of the frequency converter unit 4 thereby providing a direct voltage supply. The output bus bar means 42 have a plurality of output side bus bars 42a, 42b, 42c, 42d, 42e protruding from the unit body 40. The output side bus bars 42a, 42b are 42c adapted to be connected to a corresponding phase conductors of a three-phase load. The output side bus bars 42d and 42e are bus bars of a brake chopper circuit of the frequency converter unit 4. The output side bus bars 42d and 42e are adapted to be connected to an external brake resistor. Brake chopper circuits and external brake resistors are known in the art and therefore they are not discussed herein.

In an alternative embodiment bus bars that are connected to a direct voltage intermediate circuit of the frequency converter unit are situated adjacent bus bars adapted to be connected to a corresponding phase conductors of a three-phase load. In said alternative embodiment bus bars adapted to be connected to an external brake resistor are situated adjacent bus bars adapted to be connected to corresponding phase conductors of a three-phase power supply. In said alternative embodiment bus bars adapted to be connected to an external brake resistor would be categorized as input side bus bars because of their location. Further, bus bars that are connected to a direct voltage intermediate circuit of the frequency converter would be categorized as output side bus bars because of their location. A frequency converter unit according to said alternative embodiment could look exactly like the frequency converter unit of Figure 1a, but functionality of input side bus bars 41 d and 41e would be interchanged with functionality of output side bus bars 42d and 42e.

Both the input side bus bars 41 a, 41 b, 41 c, 41 d, 41 e and the output side bus bars 42a, 42b, 42c, 42d, 42e are located on a bus bar side wall 404 of the unit body 40. This enables connecting both power supply cabling and load cabling on a same side of the frequency converter unit 4.

Figures 2a ― 2d show side views of the frequency converter unit of Figure 1. Figures 2a, 2b and 2c show that the input side bus bars 41 a, 41 b, 41c, 41d, 41e are spaced apart in a first direction DR1, which is parallel to a vertical direction in said figures. Also the output side bus bars 42a, 42b, 42c, 42d, 42e are spaced apart in the first direction DR1.

Figure 2b shows that the input side bus bars 41 a, 41 b, 41 c, 41 d, 41e are situated on an input side bus bar line IL which lies at a first angle α₁ with respect to the first direction DR1. The output side bus bars 42a, 42b, 42c, 42d, 42e are situated on an output side bus bar line OL which lies at a second angle α₂ with respect to the first direction DR1. The absolute value of the first angle α₁ is approximately 65°. The absolute value of the second angle α₂ is substantially equal to the absolute value of the first angle α₁. The first angle α₁ has an opposite sign compared to the sign of the second angle α₂ so that angle between the input side bus bar line lL and the output side bus bar line OL is approximately 50°. The input side bus bar line lL and the output side bus bar line OL are in such an angle that they form an arrowhead shape. In alternative embodiments angle between the input side bus bar line and the output side bus bar line may be between 25° and 75°.

The frequency converter unit 4 comprises a first user interface position 481 on a first side wall 401 of the unit body 40, the first side wall 401 extending perpendicular with respect to the bus bar side wall 404. The frequency converter unit 4 also comprises a second user interface position 482 on a second side wall 402 of the unit body 40, the second side wall 402 extending perpendicular with respect to the bus bar side wall 404 and parallel with respect to the first side wall 401. Each of the user interface positions being adapted to receive a user interface unit for controlling the frequency converter unit 4.

There is a first handle position 51 on the first side wall 401 of the unit body 40. A handle 55 is received in the first handle position 51 for moving the frequency converter unit 4. The frequency converter unit 4 also comprises a second handle position 52 on the second side wall 402 of the unit body 40. The second handle position 52 is adapted to receive a handle for moving the frequency converter unit 4.

Figure 3a shows a frequency converter assembly according to an embodiment of the invention and comprising a frame 2 and the frequency converter unit 4 of Figure 1. The frame 2 comprises an input cabling panel 21 adapted to be connected to a power supply and an output cabling panel 22 adapted to be connected to a load.

The input cabling panel 21 is adapted to electrically connect the input bus bar means 41 of the frequency converter unit 4 to the power supply. The output cabling panel 22 is adapted to electrically connect the output bus bar means 42 of the frequency converter unit 4 to the load. The input cabling panel 21 comprises input contacts 21 a, 21 b, 21 c, 21 d, 21 e adapted to be connected to the input side bus bars 41 a, 41 b, 41 c, 41 d, 41 e of the frequency converter unit 4. The output cabling panel 22 comprises output contacts 22a, 22b, 22c, 22d, 22e adapted to be connected to the output side bus bars 42a, 42b, 42c, 42d, 42e of the frequency converter unit 4.

The input cabling panel may comprise cable terminals for input cables. The output cabling panel may comprise cable terminals for output cables.

The frequency converter unit 4 is adapted to be installed in the frame 2 in an installed position depicted in Figure 3b. The installation of the frequency converter unit 4 is adapted to be carried out in an installation direction ID shown by an arrow in Figure 3a. The installation direction lD is perpendicular to the first side wall 401, the second side wall 402 and the first direction DR1. The installation direction lD is parallel to the third side wall 403 and the bus bar side wall 404.

Figure 3a shows that it is essential that both the input side bus bars and the output side bus bars are spaced apart in the first direction DR1. If the input side bus bars and/or the output side bus bars were not spaced apart in the first direction, it would be impossible to get the input side bus bars adjacent to the input contacts and the output side bus bars adjacent to the output contacts simply by pushing the frequency converter unit into the frame in an installation direction.

In the installed position the input side bus bars 41 a, 41 b, 41 c, 41 d, 41 e are adjacent to the input contacts 21 a, 21 b, 21 c, 21 d, 21 e, respectively, and the output side bus bars 42a, 42b, 42c, 42d, 42e are adjacent to the output contacts 22a, 22b, 22c, 22d, 22e, respectively. The input side bus bars may be secured to the input contacts by bolts and nuts to ensure an appropriate electrical connection. Similarly, the output side bus bars may be secured to the output contacts by bolts and nuts to ensure an appropriate electrical connection. Also other detachable connecting means may be used instead of bolts and nuts.

Figure 3a shows a first cover plate 81 and a second cover plate 82 adapted to be installed on the first side wall 401 of the frequency converter unit 4. There is a user interface unit 85 mounted on the first cover plate 81. The user interface unit 85 is adapted for controlling the frequency converter unit 4. In Figure 3b the first cover plate 81 and the second cover plate 82 are installed on the first side wall 401 of the frequency converter unit 4, and the user interface unit 85 is received in the first user interface position 481.

In Figure 3a the frequency converter unit 4 is placed on a unit car 9 which is provided with wheels 92. The unit car 9 is adapted to facilitate moving of the frequency converter unit 4. Figure 3a further shows a unit ramp 11 which is adapted to facilitate pushing of the frequency converter unit 4 to the installed position.

The frequency converter unit 4 is adapted to be installed in four different types of frames. The frame 2 depicted in Figure 3a is a first type frame which is adapted to receive power supply cabling and load cabling on a left wall thereof due to the location of the input cabling panel 21 and the output cabling panel 22. A second type frame is adapted to receive power supply cabling and load cabling on a right wall thereof, which means that an input cabling panel and an output cabling panel are located on the right wall. A third type frame is adapted to receive power supply cabling and load cabling on a front wall thereof. When the frequency converter unit 4 is installed in the third type frame the power supply cabling and load cabling may be connected to the input bus bar means 41 and output bus bar means 42 directly without any cabling panels by using appropriate cable terminals. A fourth type frame is adapted to receive power supply cabling and load cabling on a back wall thereof.

A left wall of a frame is parallel to a right wall of the frame. A back wall of a frame is parallel to a front wall of the frame. Expressions left wall, right wall, front wall and back wall of a frame refer to the installation direction. The left wall and the right wall are parallel to the installation direction while the front wall and back wall are perpendicular to the installation direction. A front wall is the wall through which the frequency converter unit is moved to the installed position. In Figure 3a a front wall of the frame 2 is closer to the frequency converter unit 4 than a back wall of the frame 2. The front wall of the frame 2 is an open wall enabling pushing the frequency converter unit 4 to the installed position depicted in Figure 3b.

Figure 4a shows a frequency converter assembly according to another embodiment of the invention and comprising a frame 2' and a frequency converter unit 4'. The frame 2' comprises an input cabling panel 21' adapted to be connected to a power supply and an output cabling panel 22' adapted to be connected to a load.

The main difference between the frequency converter assembly of Figure 4a and the frequency converter assembly of Figure 3a is that the installation direction ID' of the frequency converter assembly of Figure 4a is perpendicular to the bus bar side wall of the frequency converter unit 4', and that the input cabling panel 21' and the output cabling panel 22' are located on a back wall of the frame 2'. In other words, the frame 2' is the fourth type frame described earlier.

There are two differences between the frequency converter unit 4' of Figure 4a and the frequency converter unit 4 of Figure 3a. The first difference is that the input side bus bars 41 a - 41 e and the output side bus bars 42a - 42e of the frequency converter unit 4 have been replaced with blade contacts adapted to co-operate with blade receiving input contacts 21 a' - 21 e' and blade receiving output contacts 22a' - 22e', respectively. The use of blade contacts and their counterparts ensure reliable electrical contact between the frequency converter unit 4' and input/output cabling without any additional securing operation. This is an advantageous feature in assemblies where the installed position is such that it would be difficult to carry out any securing actions due to lack of space for example. However, it should be understood that blade contacts or other type of fast coupling connectors may be used in all types of frequency converter assemblies according to present invention. Herein fast coupling connector means any electrical connector type that achieves reliable electrical contact simply by pushing a contact member into its counterpart.

The second difference is that there is a third handle position 53' on a third side wall 403'. A handle 55' is received in the third handle position 53' for moving the frequency converter unit 4'. The handle 55' is identical with the handle 55.

In Figure 4a the frequency converter unit 4' is placed on a unit car 9' which is provided with wheels 92'. The unit car 9' is adapted to facilitate moving of the frequency converter unit 4'.

Several frequency converter assemblies according to above described embodiments may be installed side by side. It is also possible to install several frequency converter assemblies one on the other. Although the first side wall, the second side wall, the third side wall and the bus bar side wall are vertical walls in the above described embodiment, it is clear that in further embodiments the first side wall or the bus bar side wall may be a horizontal wall.

It will be obvious to a person skilled in the art that the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.