Abstract:
Data memories are used to represent the characteristic values of the properties of the circuit-breaker and the associated current transformer. A cable harness uses a writeable electronic memory module which is inserted into one of the interconnecting cables between the current transformer(s) and the overcurrent trip as the data memory.

Description:
This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/DE01/01489 which has an International filing date of Apr. 9, 2001, which designated the United States of America and which claims priority on German Patent Application number DE 100 19 092.8 filed Apr. 12, 2000, the entire contents of which are hereby incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention generally relates to a low-voltage circuit breaker having a data memory. Preferably, the data memory is for passing characteristic values of the circuit breaker and/or of the associated current transformer to an electronic overcurrent release. Additionally, it preferably includes at least one connection line between the current transformer or transformers and the overcurrent release. 
     BACKGROUND OF THE INVENTION 
     Circuit breakers are known which have a data memory which stores unchangeable characteristic values for the circuit breaker such as the type and rating current as well as characteristic values for the connected current transformer. When a release is replaced, data from the data memory is read to the release which has been inserted, and which then need not be reconfigured. 
     EP-B 0 493 272 discloses a circuit breaker which has an adapter board which is permanently connected to it and to which the release is connected. The adapter board includes a device for mapping the type and/or rating of the circuit breaker, as well as an output plug connector, which is connected to the release. 
     WO 97/08 725 discloses a further circuit breaker, whose data memory is mounted detachably on one side of the housing. This means that the data memory is also always included in the testing of the overcurrent release. If only the overcurrent release is intended to be replaced, then the data memory is disconnected from the overcurrent release and is attached to the new release, so that the characteristic values of the circuit breaker are transferred. However, during the process, there is a risk of the data memory being mislaid or confused in the course of the replacement of the release. Furthermore, the arrangement is susceptible to defects, due to the large number of plug connections in it. 
     In order to minimize the plug connections, it has also already been proposed for the data memory to be arranged as component of a two-part plug connection on the connection line between the current transformer and the overcurrent release, whose second component belongs to the overcurrent release. However, accommodation of the data memory in a plug part requires a specially designed component, which must be fitted with resistors individually for each switch type. The number of parameters which can be stored is, furthermore, small in this case. 
     SUMMARY OF THE INVENTION 
     An embodiment of the invention is based on the object of specifying a low-voltage circuit breaker in which the data memory operates in an improved manner, and whose construction is simple. 
     According to this, an electronic memory module which can be written to can be used as the data memory, and can be inserted into one of the connection lines between the current transformer or transformers and the overcurrent release. 
     An EEPROM, by way of example, can be used as the memory module. In order to avoid injected interference, the memory module should expediently be arranged toward the release-side end of the connection line. The memory module can include its own housing, through which the connection line runs. 
     On the one hand, the solution has the advantage that a sufficiently large number of parameters can be stored. The coding can be carried out in the course of testing the switch. On the other hand, normal standard plugs can be used for the plug connector. Overall, the connection line from the current transformer or the current transformers becomes a standard component in the switch manufacturing process in which the parameters of the associated switch are stored in the course of switch testing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be explained in more detail in the following text with reference to an exemplary embodiment. In the associated drawings: 
     FIG. 1 shows a cable harness for connecting the current transformer of a circuit breaker to the overcurrent release. 
     FIG. 2 shows the associated circuit of the cable harness. 
     FIG. 3 shows a schematic illustration of a low-voltage circuit breaker with a cable harness as shown in FIGS.  1  and  2 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a cable harness for the connection of an overcurrent release  18  (FIG. 3) to converter sets  17  (FIG.  3 ). Each converter set  17  in this case includes, in a known manner, a current transformer  19  and a power transformer  20 . Three plugs  2  firstly create the connection for three such transformer sets  17  which supply the measurement current of each pole or of each switching contact system  12  of the three-pole circuit breaker  10  (FIG. 3) for its overcurrent release  18 , and on the other hand provide auxiliary power for the operation of the overcurrent release  18 . The individual lines are connected by cable ties  3  to form the cable harness  1 . The other of the two ends of the cable harness  1  are fitted with plug connectors  4  and  5  for connection to the overcurrent release  18 , on the one hand for the measurement current and on the other hand for the power supply. 
     A housing  6  is inserted in the measurement line run, in which housing  6  an EEPROM 7 is accommodated as a data memory for the characteristic values of the circuit breaker  10  and/or of the current transformers  19 , or of the overall transformer set  17 . 
     FIG. 2 shows the line run within the cable harness  1  and the housing  6 . Two lines for one phase are respectively used as the forward line and return line for the supply current, and two twisted lines are in each case used as the forward line and return line for the measurement current. The twisting is identified by a zigzag line in FIG.  2 . The lines pass through the housing  6  in which the EEPROM 7 is located. In the present case, this is a four-wire element; however, two-wire elements in the form of button cells are also available as EEPROM&#39;s, and these would allow the plug contact points to be further miniaturized. 
     FIG. 3 illustrates the use of the described cable harness  1  for a low-voltage circuit breaker  10 . The circuit breaker  10  has, in a known manner, a housing  11  in which a switching contact system  12  with an associated quenching chamber  13  and a drive apparatus  14  for joint operation of all the switching contact systems  12  which are present are accommodated, for each pole. Each switching contact system  12  has an upper connecting rail  15  and a lower connecting rail  16 , in order to connect the circuit breaker  10  to a circuit. Each lower connecting rail  16  has an associated transformer set  17 , which detects the current flowing via the associated switching contact system  12  and provides auxiliary power for the operation of an electronic overcurrent release  18 . As already mentioned, each transformer set  17  for this purpose has a current transformer  19  and a power transformer  20 . 
     The connection rails  15  and  16  as well as the transformer sets  17  are located on the rear face of the housing  11 , while the electronic overcurrent release  18  is arranged on the opposite front face of the housing  11 . In order to connect the transformer sets  17  to the overcurrent release  18 , the cable harness  1  is made in some suitable manner in the lower region of the housing  11 . As can be seen, the housing  6  for the memory module is located close to the overcurrent release  18 . 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.