Rated current module

Abstract

Rated current module (43, 59, 74, 92), with - a memory in which a value for the rated current is stored, - Interfaces for attachment to an overcurrent release and for transmitting the rated current value to the overcurrent release, characterized in that - the rated current value stored in the memory can be changed when the rated current module (43, 59, 74, 92) is attached to the overcurrent release, and - the rated current module (43, 59, 74, 92) comprises a display and is designed to display the rated current value stored in the memory by means of the display.

Description

[0001] The invention relates to a rated current module, an overcurrent release with a rated current module and a method for changing the rated current of an overcurrent release.

[0002] The standards IEC 60947 Part 1 and Part 2 specify general rules and safety requirements for low-voltage switchgear. Low-voltage circuit breakers, such as molded-case circuit breakers (MCCBs) and air circuit breakers (ACBs), are generally designed according to these standards. The manufacturer specifies a rated current "In" (formerly: nominal current - below, the term is used synonymously with rated current) that the device can continuously carry without damage under standardized conditions (connection cross-sections of the copper conductors and their lengths) at an ambient temperature of up to 40°C. This is how the "circuit breaker" system component of a power distribution system is designed. The product standard DIN EN 60947-1 / -1 stipulates: 4.3.3.3 Rated current (I n ) ...

[0003] For circuit breakers, the rated current is the rated uninterrupted current (I u ) (see IEC 60947-1:2007, 4.3.3.4) and equal to the conventional thermal current in free air (I th ). 4.3.2.1 Conventional thermal flow in free air (I th ) ...

[0004] The conventional free-air thermal current is the maximum test current for temperature-rise tests of open-circuit devices in free air (see 8.3.3.3). The conventional free-air thermal current must be at least equal to the maximum rated operational current (see 4.3.2.3) of the open-circuit device during eight-hour operation (see 4.3.4.1).

[0005] Free air is understood to mean air in normal indoor spaces, almost free from drafts and radiation.

[0006] The circuit breaker, with every connection type intended for its rated current In, must comply with the product standard regarding the maximum permissible heating of its connections and the maximum permissible temperatures of its insulating materials. This is ensured by the circuit breaker manufacturer through test certificates. However, this is always tested under standardized "best-case conditions." If a design or connection type does not yet achieve the intended rated current of the device variant when the temperature limit values ​​are reached, it is only permitted for the next lower rated current. The rated currents follow a preferred series: 630A; 800A; 1000A; 1250A; 1600A; 2000A; 2500A; 3200A; 4000A; 5000A; 6300A. There are no intermediate values. The rated currents can often be changed by changing a part called a “rating plug” in the electronic module of the overcurrent release.Dabei können nur kleinere Nennströme, unterhalb des thermischen Stromes Ith gewählt werden.

[0007] Eine Definition findet sich in der Leistungsschalternorm UL489 (da im amerikanischen Markt seit langer Zeit üblich): 2.66 RATED CURRENT (I n ) - the marked current rating and the maximum RMS current a circuit breaker can carry continuously without tripping and the maximum current the circuit breaker will carry without changing, deleting, or adding a part or parts such as trip units and rating plugs. See also current setting (I r ). 2.24 CURRENT SETTING (I r ) - the rms current an adjustable circuit breaker is set to carry continuously without tripping. It is normally expressed as a percentage of the rated current and is adjustable. 2.86 TRIP UNIT - a self-contained portion of a circuit breaker that is interchangeable and replaceable in a circuit breaker frame by the user. It actuates the circuit breaker release mechanism and it sets the Rated Current (I n ) of the circuit breaker unless a rating plug is used. See also rating plug. 2.70 RATING PLUG - a self-contained portion of a circuit breaker that is interchangeable and replaceable in a circuit breaker trip unit by the user. It sets the Rated Current (In) of the circuit breaker.

[0008] The protective tripping is adapted to the respective load feeders using a setting value for the overload protection Ir on the circuit breaker's overcurrent release. Depending on the standard (IEC, NAFTA), the cross-sections of the cabling or busbar must be designed to the rated value, which cannot be increased by adjusting a knob, e.g., the "In" value of the rating plug. Design of an energy distribution system:

[0009] The design of the "switchgear for power distribution" (power distribution system) system follows the standard DIN EN 61439 Parts 1 and 2. With regard to continuous current load and compliance with temperature rise limits, the power loss contributions of all installed components and any ventilation openings in the enclosure are taken into account. Specifically, the following rated values ​​are specified in the standard DIN EN 61439: Inc. Rated current of a main circuit. Rated current that a main circuit can carry if it is the only circuit in a cubicle of a switchgear and controlgear assembly that carries a current. (Section 3.8.10.5) Approximately: max. load current in a cubicle (maximum single load) Ing Rated operational current of a main circuit Rated current that a main circuit can carry taking into account the Mutual thermal influences of other circuits that are simultaneously loaded in the same panel of the switchgear assembly. (Section 3.8.10.6) e.g.: max. load current of one outgoing circuit if several outgoing circuits in the panel carry load current InA Rated current of a switchgear assembly. Rated current that can be distributed through a switchgear assembly without exceeding the specified temperature limit of the various parts. (Section 3.8.10.7) approximately: max. current load of the main busbars IB: Designated operating current (of a circuit): Electric current intended to be carried by an electrical circuit during normal operation. (Section 3.8.10.8) For example: Design value of a specific outgoing circuit based on the specific load. RDF rated diversity factor Value calculated by dividing the rated operational current of the outgoing main circuit Ing by the rated current Inc of the same outgoing main circuit, where Ing and Inc were determined from tests. (Section 3.8.10.11) for example: Simultaneity factor: How much Ing comes out of the given Inc? RDF = 100% means that one circuit is not influenced by another in the same field. RDF = 50% means that the current carrying capacity is halved due to heating of the neighboring device.

[0010] The design of a power distribution switchgear therefore requires regular tests to determine the permissible continuous currents Inc or Ing of a specific circuit-breaker type in a specific switchgear panel design. Due to the variety of connection types, installation heights, and the heating contributions of other devices, new limits for the continuous current load are constantly emerging. These maximum permissible continuous currents do not follow the coarsely spaced rated current gradations of the circuit-breakers (see above). A more precise adjustment option, which the switchgear panel installer can specify, would be useful here. Example:

[0011] A 4000A circuit breaker (Ith = 4000A; possible In values ​​of the rating plug: 4000A; 3200A; 2500A, ...; protective tripping adjustment knob: Ir = 40%...100% In) is selected. Tests show that this breaker, in the panel's installation situation with standard ventilation according to IP20 protection level, can carry a current Inc of 3700A, whereas with a closed enclosure according to IP55 protection level, it can only carry a current Inc of 3100A. It would be useful to be able to set the circuit breaker to the values ​​In = 3700A or In = 3100A using a rating plug.

[0012] This setting can currently only be changed via the IR setting knob on the protective trip. However, this setting is easily "tricked" because the setting knobs are usually accessible from the outside of the switchgear. A sealable cover is usually available, but it does not prevent incorrect operation or misuse.

[0013] In circuit breakers, primarily ACBs, replaceable rating plugs are mounted in or on an electronic trip unit (ETU). This module contains electronic means for encoding the rated current "In" and communicating it to the ETU. The advantage of outsourcing the storage of the In value to a separate, customer-replaceable module is the ability to create a uniform ETU hardware and firmware across all sizes and rated currents. Changing the rated current requires neither current sensors nor ETUs to be replaced; no modification of the internal wiring is necessary.

[0014] The standard requires protection against the operation of the circuit breaker: - without rating plug; and - with too high current In in the rating plug, which would exceed the free air thermal current Ith of the circuit breaker.

[0015] Furthermore, the standard requires that the rating plug cannot simply be replaced manually; a tool must be used for replacement. This means that only qualified electricians should perform this replacement, who have also tested the current-carrying capacity of the cabling or busbar for the higher continuous current.

[0016] Document DE39 26 414 B4 shows an electrical circuit breaker containing an electronic trip unit connected to a removable digital display and keypad unit via an electrical connector on the outside of the circuit breaker housing. The digital display and keypad unit provides a user interface for displaying the trip unit parameters and entering the trip unit settings. Since the trip unit settings are only accessible via this user interface when connected to the circuit breaker, unauthorized access to the trip unit settings is prevented.

[0017] Furthermore, document EP3 341 953 B1 discloses a circuit breaker comprising a frame, a trip unit, and a frame module. The frame module has a first interface structured for connection to the trip unit, a second interface structured for connection to the frame, and a current rating storage unit structured for storing a current rating associated with the frame and for providing the stored current rating in the trip unit when the trip unit is connected to the first interface.

[0018] Furthermore, document DE 10 2016 221 093 B4 discloses a circuit breaker for interrupting an electrical circuit when adjustable protection parameters are exceeded, comprising an electronic trip unit in which the set protection parameters are stored and a movable sealing disc that covers at least part of the circuit breaker. The circuit breaker has a sensor with which a first state of the sealing disc can be determined. The electronic trip unit is designed such that changes in the protection parameters are only accepted by the electronic trip unit when the sealing disc is in its first state.

[0019] Furthermore, document EP 2 652 765 B1 shows how to read a parameter value to be shown on the display from a device's setting device. The setting device has a device for reading the set value. The parameter value can be transmitted from the setting device to the display at a constant frequency or as a one-time message only when the parameter value has been changed.

[0020] The invention aims to make the setting of a rated current more flexible.

[0021] This object is achieved by a rated current module according to claim 1, an overcurrent release according to claim 6 and a method for changing the rated current of an overcurrent release according to claim 11.

[0022] A rated current module - hereinafter also referred to as "rating plug" - is proposed which has a memory (e.g. EEPROM) in which a value for the rated current is stored, and interfaces for attachment to an overcurrent release - hereinafter also referred to as ETU - and for transmission of the rated current value to the overcurrent release.

[0023] During the assembly of the circuit breaker at the manufacturer's, the rated current module can be programmed for the first time to the maximum possible rated current; this maximum value remains unchanged. According to the invention, the rated current value stored in the memory can be changed when the rated current module is attached to the overcurrent release.

[0024] In addition, the rated current module has a display configured to show the rated current value stored in the memory. This display is preferably an electronic display, e.g., an E-Ink display, i.e., an electrophoretic display. An E-Ink display has the advantage that only the change in the displayed value requires energy, not the display itself.

[0025] The rated current module may be equipped with a device (e.g., a knob or buttons) for changing the rated current value. Protection against unintentional changes to the rated current value may be provided (e.g., a cover that must be removed).

[0026] An alternative or supplementary variant of the subject matter of the invention provides for a change in the rated current value by input means of an overcurrent release to which a rated current module according to the invention is connected. In this case, the overcurrent release has a device (e.g., rotary knob or buttons) for entering a changed rated current value and is designed to transmit the rated current value to the rated current module. The rated current module is then configured to replace the rated current value stored in its memory with the transmitted value. This variant can also provide protection against unwanted changes to the rated current value. This can directly affect the input means (e.g., a cover that must be removed). However, the protection can also consist of requiring a button to be held down during input.Such a solution has the advantage that an input device of the overcurrent release already provided for another purpose can be provided for changing the rated current value. The device for entering the rated current value is then an input device intended for another input (e.g., a rotary coding switch for setting a tripping parameter), and the overcurrent release is then designed to switch to a mode in which the rated current value can be entered using the input device. For this mode change, a button can be arranged on the housing of the overcurrent release, for example, with which the mode change can be carried out (either changing modes by pressing the button or, preferably—as already mentioned above—entering the rated current value only when the button is pressed).

[0027] According to one embodiment, the overcurrent release is configured so that the rated current value can only be changed within a range defined by a predefined rated current value. This could be the initial value of the rated current (i.e., the value stored in the memory of the rated current module upon delivery and possibly indicated on the module). A change could then be provided, for example, in a range from 80% to 120%. However, a variant is preferred in which the range is based on the thermal current Ith stored in the overcurrent release, e.g., a range from 70% to 100% Ith.

[0028] The invention also relates to a circuit breaker (in particular a low-voltage circuit breaker) with an overcurrent release according to the invention, e.g. an ACB or an MCCB.

[0029] The invention also relates to a method for changing the rated current of an overcurrent release according to the invention. This method provides for a rated current value in the memory to be replaced by an entered value and displayed on the display. The display can be updated periodically. In this case, a further development of this method is particularly useful in which an update of the display is triggered by the restoration of the full power supply to the overcurrent release after a power interruption or after a sleep mode phase of the overcurrent release. This ensures that the displayed value is correct immediately after the power supply is restored and not only after a scheduled refresh.

[0030] The invention offers the advantage of more flexible adjustment of the rated current. This is particularly helpful in situations where a manufacturer supplies a circuit breaker according to the invention (with a rated current module) to a switchgear cabinet builder. The switchgear cabinet builder must adapt the rated current to the specific conditions of the respective switchgear cabinet. The adaptability of the rated current according to the invention helps them achieve this. For example, replacing the rated current module typically supplied by the manufacturer with the circuit breaker will be required in fewer cases.

[0031] The invention is described in more detail below within the framework of an exemplary embodiment with reference to the figures. They show: Fig. 1a: a conventional rating plug, with printed setting value, Fig. 1b: a rating plug extended by function settings (also called a “function module” or “function plug”), Fig. 2a, Fig. 2b and Fig. 3a, Fig. 3b: Typical arrangements of a rating plug or a function plug in an ETU module, Fig. 4 and Fig. 5: Mounting a rating plug on an ETU, Fig. 6: schematic representation of a conventional rating plug, Fig. 7: schematic representation of a rating plug according to the invention, and Fig. 8: Possible position of a button on an ETU, which must be pressed to adjust the rated current.

[0032] Fig. Figure 1a shows a conventional rating plug for setting the rated current In to 1250 A. Such rating plugs are inserted into electrical overcurrent trip modules (ETUs) of circuit breakers to set the rated current to the value stored in the module. The ETUs are equipped with corresponding slots or interfaces for this purpose.

[0033] Siemens offers rating plugs that allow for additional settings. These can be used, for example, to determine or set the basic protection functions of a circuit breaker. An example is shown in Fig. 1b. These extended rating plugs are also referred to as "function modules" or "function plugs" and are to be subsumed under the term "rated current module" or "function plug" for the purposes of this application.

[0034] Typical arrangements of rating plugs or rated current modules in ETU modules are shown by Fig. 2a and Fig. 2b and Fig. 3a and Fig. 3b. These show front views of ETUs as used in ACBs (e.g. Siemens 3WL circuit breakers). The rating plugs (in Fig. 2a and Fig. 3a for a rated current In of 3000 A). These rating plugs can be replaced, for example, to reduce the rated current.

[0035] Fig. 4 and Fig. 5 shows variants of the installation of rating plugs. Fig. Figure 4 concerns the installation of a rating plug with a locking hook. Unlocking 100 is performed using a screwdriver 101.

[0036] Circuit breakers are often equipped with a rating plug to protect against the setting of excessively high rated currents. A corresponding procedure is described, for example, in EP 1328955 A1. Rejection of a rating plug with a rated current In > Ith is performed, for example, by a plausibility check of the ETU during commissioning. In the event of a fault, the smallest permissible rated current In is used and signaled by a red "Error" LED. The circuit breaker would then trip and shut down. Fig. Figure 5 shows another variant for installing a rating plug. Locking is achieved using a bayonet bolt that can be rotated 90° using a screwdriver. Pulling the bolt triggers the circuit breaker.

[0037] Fig. Figure 6 shows a very simplified representation of a rating plug. It consists of a memory, e.g., EEPROM, and an interface. This interface represents three interfaces: a mechanical one (for attaching the rating plug to the ETU), an electrical one (for supplying the rating plug with power via the ETU), and a digital one (for reading the rated current value stored in the rating plug's memory or transmitting it to the ETU).

[0038] A more concrete example of the structure of a rating plug is shown in US 6836396 B1, where the rating plug is equipped with an energy storage device (battery). Often, as in Fig. 6 - this was waived and a supply by the ETU was provided.

[0039] According to the invention, a rating plug is proposed which, after being attached to an ETU, can be set to a value less than the thermal current Ith of the circuit breaker within a predetermined range, e.g. by a switchgear cabinet manufacturer, and which displays this setting value on a display located therein. Fig. Figure 7 shows a schematic of such a rating plug. The rating plug is equipped with a display that shows the value of the rated current In stored in the memory. The display is also powered by the ETU (in Fig. 7 not shown). The value for the rated current stored in the memory can be changed or adjusted.

[0040] Preferably, the rated current value is set using the setting means already present on a circuit breaker to which the rating plug has been attached (see Fig. 2 and Fig. 3). In this configuration, the ETU can write a rated current value entered on the ETU to the rating plug's memory, which is then output on the display.

[0041] The adjustability of the rated current of the circuit breaker In, for example, to the rated current of a main circuit Inc or the rated operating current of a main circuit Ing at the location of the circuit breaker, within a specified range smaller than the thermal current Ith of the circuit breaker, makes it easier for a switchgear manufacturer to adapt the circuit breaker to the application situation in a switchgear cabinet. The setting range of the rating plug according to the invention is preferably 70% to 100% of the thermal current Ith of the circuit breaker. An additional reduction of the setting value for the overload trip to adapt it to the connected load at the location of the switchgear can be achieved in the electronic overcurrent release using the setting knob / menu item “Ir” for the overload protection value. A typical setting range for this is 40%....100% of the rated current In.

[0042] It can be provided that the default value for the rated current In can only be set if a laterally positioned button of the circuit breaker, accessible after removing the front cover, is pressed, e.g., for the duration of the setting. This fulfills the requirement of tool-dependent accessibility, as this is necessary for removing the front cover. A possible position of such a button is shown in Fig. 8. With this solution (setting only while the button is pressed), it would also be conceivable that the rated current Ir is set using the setting means for setting the overload release value in the electronic overcurrent release (e.g. setting knob / menu item "Ir" for the overload protection value).

[0043] Generally, the button and setting options can be provided either in the electronic trip unit (ETU) or on the rating plug itself. The ETU often has buttons for parameter setting, the values ​​of which are displayed on screens.

[0044] A permanent display, such as the type known as "e-paper" or "Eink" displays, can be used to indicate the set value for the rated current In on the rating plug. The latter are characterized by the fact that they only require power to change the display and, if necessary, to update or refresh the display. The display can be implemented, for example, as a single-line, four-digit digital display.

[0045] The rating plug display can be updated or refreshed periodically with the currently set value for the rated current In, using the power of the self-powered ETU when the electronic overcurrent release is activated. In particular, an update can also be scheduled whenever the (full) power supply to the ETU is restored after an interruption or a sleep mode of the ETU. Explanation of the figures:Figure 1BFunction module

[0046] The function module determines the rated current and the basic protection functions of the electronic trip unit of the 3WA circuit breaker 1 article number (on the top, not visible when plugged in) 2 Rated current 3 basic protection functions 4 Country of manufacture (on the bottom, not visible when plugged in)

[0047] In order to adapt the circuit breaker to changing requirements, the function module is replaceable. Figure 2A 21 Option: Safety lock prevents accidental pressing of the reset button after overcurrent tripping 22 Option: Alphanumeric display 23 pages down 24 Display error in the overcurrent release 25 Thermal memory On / Off N-conductor protection On / Off Setting value N-conductor overload Switching overload characteristic |2t / |4t 26 Rotary coding switch delay overload release 27 Rotary coding switch delay short circuit release 28 Display trigger cause 1) 29 Sealing eyelet 30 Option: Earth fault protection module 31 Displays Ground fault alarm Ground fault triggered 32 rotary coding switch delay earth fault protection tg / | 2 tg 33 Delete key 34 Test socket 35 Query button 36 Test button 37 Rotary coding switch setting value earth fault alarm 38 Rotary coding switch setting value earth fault protection 39 Earth fault detection switch 2 ) 40 Rotary coding switch setting value short-circuit protection 41 Rotary coding switch setting value short-time delayed 42 Rotary coding switch setting value overload release 43 Rated current module 44 displays Overcurrent release activated Overload alarm COMMUNICATION EXTENDED 45 pages and up 46 Mechanical RESET for restart lock Figure 2B 51 ETU TRIP: Indication of a trip and mechanical RESET of the reclosing lock after a trip by the electronic trip unit ETU300 52 Lockable cover with safety lock, prevents manual resetting of the restart lock (option) 53 function keys CLEAR and TEST 54 LED displays 55 rotary coding switches 56 Query button to display the last trigger reason when the ETU300 is not activated 57 Interface for activation with an external voltage 58 Sealing eyelet for sealable cover (option) 59 Function module Rated current module Figure 3A 61 Option: Safety lock prevents accidental pressing of the reset button after overcurrent tripping 62 Graphic display 63 Display error in the overcurrent release 64 control buttons for setting the trigger parameters 65 Sealing eyelet 66 Displays Ground fault alarm Ground fault triggered 67 fields for recording the setting values 68 Delete key 69 Test socket 70 Query button 71 Test button 72 fields for recording the setting values 73 Option: Earth fault protection module 74 Rated current module 75 Display trigger cause 1) 76 Displays Overcurrent release activated Overload alarm COMMUNICATION 77 Mechanical RESET for restart lock Figure 3B 81 ETU TRIP: Indication of a trip and mechanical RESET of the reclosing lock after a trip by the electronic trip unit ETU600 82 USB port (USB-C) 83 EXT TRIP: Indication of a trip and mechanical RESET of the reclosing lock after an external shutdown 84 Lockable cover with safety lock, prevents a RESET of the restart lock (option) 85 Display 86 function keys F1 to F4 84 LED displays 88 rotary coding switches 89 Query button for querying the last trigger reason when the ETU600 is not activated 90 Sealing eyelet for sealable cover 91 Voltage measuring module VTM (option) 92 Function module Rated current module Figure 8 102 Slot for rating plug 103 Possible side space for button “I n -setting“

Claims

[1] Rated current module (43, 59, 74, 92), with - a memory in which a value for the rated current is stored, - Interfaces for attachment to an overcurrent release and for transmitting the rated current value to the overcurrent release, characterized by , that - the rated current value stored in the memory can be changed when the rated current module (43, 59, 74, 92) is attached to the overcurrent release, and - the rated current module (43, 59, 74, 92) comprises a display and is designed to display the rated current value stored in the memory by means of the display. [2] Rated current module (43, 59, 74, 92) according to claim 1, comprising a device for changing the rated current value. [3] Rated current module (43, 59, 74, 92) according to claim 2, characterized by that it is formed with protection against unwanted changes in the rated current value. [4] Rated current module (43, 59, 74, 92) according to one of the preceding claims, characterized by that the display is an electronic display. [5] Rated current module (43, 59, 74, 92) according to claim 4, characterized by that the electronic display is an E-Ink display. [6] Overcurrent release with a rated current module (43, 59, 74, 92) according to one of claims 1 to 5, characterized by , that - the overcurrent release has a device for entering a changed rated current value and is designed to transmit the rated current value to the rated current module (43, 59, 74, 92), and - the rated current module (43, 59, 74, 92) is designed to replace the rated current value stored in its memory with the transmitted value. [7] Overcurrent release according to claim 6, characterized bythat it is formed with protection against unwanted changes in the rated current value. [8] Overcurrent release according to claim 6 or 7, characterized by , that - the device for entering the rated current value is an input device intended for the input of other information, and - the overcurrent release is designed to switch to a mode in which the rated current value can be entered using the input device. [9] Overcurrent release according to claim 8, characterized by that a button is located on the housing of the overcurrent release with which the mode change can be carried out. [10] Overcurrent release according to one of the preceding claims, characterized by that it is designed so that the rated current value can only be changed within a range defined by a specified rated current value. [11] Circuit breaker with an overcurrent release according to one of claims 6 to 10. [12] Method for changing the rated current of an overcurrent release according to one of claims 6 to 10, comprising - replacing a rated current value of the memory with an entered value, and - Display the newly stored rated current value in the memory using the display. [13] Method according to claim 12, characterized by Triggering an update of the display by restoring full power to the overcurrent release after a power interruption or after a sleep mode period of the overcurrent release.

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