DE102013111954B4 - Attachable module for a contactor and a contactor with such a module - Google Patents

Abstract

Plug-in module (10) designed for retrofitting a contactor (12) with semiconductor switches (16) which can be connected in parallel with switching contacts (14) of the contactor, - a control (18) for the semiconductor switch (16) which is designed depending on the control (18) of the contactor (12) to control the semiconductor switches (16) during a switching on and / or off process of the contactor (12) in such a way that the switching contacts (14) switch almost without power, and an integrated motor protection circuit (20, 22), which has motor protection tripping electronics (20) and at least one current transformer (22) for contactless measurement of an electrical current, the tripping electronics (20) being designed to continuously measure an electrical current without contact via the at least one current transformer (22) and upon leaving a predetermined nominal current range by the measured current to send a shutdown signal to the control (18) to initiate a shutdown process.

Description

The invention relates to a plug-on module for a contactor and a contactor with such a module.

The service life of contactors is influenced, among other things, by the currents to be switched and the number of switching operations. A contactor is usually subjected to a particularly high load when controlling electrical machines such as motors, since high switch-on and switch-off currents occur, for example when motors are started. Such high currents often lead to faster wear of the switch contacts and thus to a reduced service life of the contactor.

In order to protect the switching contacts of a contactor from such high currents, triacs or thyristors connected to one another can be connected in parallel to the switching contacts, which pick up the currents during the switching on or off process, as is the case, for example, in U.S. Patent 4,152,634 is described.

The German published application DE 103 15982 A1 relates to a hybrid electromagnetic direct current contactor or switch, and in particular to a hybrid electromagnetic direct current contactor, which is able to prevent an arc from occurring when opening / closing a hybrid-structured contactor and a leakage current by connecting a semiconductor switch in parallel with a mechanical contact switch to minimize. This document also shows that an arc extinguishing unit of a conventional electromagnetic contactor can be removed and, for example, a semiconductor switching unit can be installed as a module in order to obtain the hybrid electromagnetic direct current contactor.

The German patent specification DE 196 19 437 C2 describes a switching device that uses the temporal dependence of the voltage signal on its main switching point in order to achieve a particularly rapid and safe control of its semiconductor switch.

The U.S. patent US 5,578,980 B1 describes a hybrid switch comprising: an electromagnetic contactor for conducting a current flow after the turn-on operation; a semiconductor switching device connected in parallel with a main contact of the electromagnetic contactor to perform turn-on and turn-off operations of a current; and a semiconductor unit body having a square cross-section housing for accommodating the semiconductor switching device and circuit boards each connected to terminals of the semiconductor switching device and pulled out from the sides of the housing, and end portions of the circuit boards are bent to form main circuit terminals, the semiconductor Unit body is mounted on an upper portion of the electromagnetic contactor and the main circuit connections of the circuit boards pulled out of the semiconductor unit body are each fastened to main circuit connections of the electromagnetic contactor using connecting screws.

The object of the present invention is now to provide a possibility of being able to retrofit a conventional contactor, if necessary, with protection against high currents during switch-on and switch-off processes.

This object is solved by the subject matter of the independent claims. Further embodiments of the invention are the subject of the dependent claims.

One idea on which the present invention is based is to create a plug-on module for a contactor, which has semiconductor switches which can be connected in parallel to the switching contacts of the contactor and a control for the semiconductor switches which controls the semiconductor switches during a switching on and off process of the contactor, that the switch contacts switch without power.

One embodiment of the invention relates to a plug-on module for a contactor with semiconductor switches that can be connected in parallel with the contactor's switching contacts and a control for the semiconductor switches, which is designed to control the semiconductor switches during an on and / or off operation of the contactor depending on the control of the contactor that the switch contacts switch almost without power. With such a module, a contactor can be retrofitted with little wiring.

The semiconductor switches can be implemented by triacs or thyristors connected to one another. With appropriate design, triacs or thyristors connected to one another can withstand relatively high currents, such as occur especially when motors are switched on.

The control can be designed to first close the semiconductor switches during a switch-on process, then to close the switch contacts and then to open the semiconductor switches, and / or to close the semiconductor switches after a switch-off process, then to open the switch contacts and then to open the semiconductor switches . Such a control can ensure that switch the switching contacts of the contactor almost without power, since the semiconductor switches connected in parallel are closed during opening or closing of the switching contacts, so that the high currents that occur when switching on or off flow through them.

The module also has an integrated motor protection circuit. In particular, the module can have trigger electronics for this purpose and a current transformer per phase, which, depending on the output signals of the current transformers, controls a shutdown of the power supply to the motor, in particular if the currents are too high, causes a shutdown of the motor power supply.

Furthermore, the module can have a housing with a base plate, which has contacts with which the module can be plugged onto corresponding contactors of the contactor. The contacts on the base plate serve both as an electrical connection between the module and the contactor and as a fixation for the module on the contactor.

Another embodiment of the invention relates to a contactor with a head plate and mating contacts for mounting or contacting with plug contacts of a pluggable module according to the invention and as described herein. The mating contacts of the contactor are connected in particular to the switching contacts of the contactor and thus enable the protective functions of the contactor to be expanded through the pluggable module.

Further advantages and possible uses of the present invention result from the following description in connection with the exemplary embodiments shown in the drawings.

In the description, in the claims, in the abstract and in the drawings, the terms and associated reference symbols used in the list of reference symbols given below are used.

• 1 ein Schaltungsdiagramm eines Ausführungsbeispiels des aufsteckbaren Moduls gemäß der Erfindung;
• 2 und 3 zwei verschiedene Ansichten eines Schützes mit einem Ausführungsbeispiel eines aufsteckbaren Moduls gemäß der Erfindung in geöffneter Ansicht;
• 4 und 5 zwei verschiedene Ansichten des in den 2 und 3 gezeigten Schützes mit dem aufsteckbaren Modul gemäß der Erfindung in geschlossener Ansicht; und
• 6 eine Ansicht des in den 2 und 3 gezeigten Schützes mit dem aufsteckbaren Modul gemäß der Erfindung in aufgestecktem Zustand.

The drawings show in

• 1 a circuit diagram of an embodiment of the plug-on module according to the invention;
• 2nd and 3rd two different views of a contactor with an embodiment of a plug-on module according to the invention in an open view;
• 4th and 5 two different views of the in the 2nd and 3rd shown contactor with the plug-on module according to the invention in a closed view; and
• 6 a view of the in the 2nd and 3rd shown contactor with the plug-in module according to the invention in the plugged-in state.

In the following description, identical, functionally identical and functionally related elements can be provided with the same reference symbols. Absolute values are given below by way of example only and are not to be understood as limiting the invention.

1 shows a circuit diagram with the components of a plug-on module for retrofitting a contactor provided for a three-phase electronic motor starter with protection against high currents during switch-on and switch-off processes. There are three switches from the electrical circuit of the contactor 14 (corresponding to three mechanically switchable switching contact pairs), which three windings T1 , T2 and T3 a motor with one of the three phases L1 , L2 and L3 connect electrically. These switches are in the contactor housing 12th (see the 2-6 ) arranged. The rest in 1 The elements shown are part of the electronics of the plug-in module: three triacs 16 as a semiconductor switch, one of which is parallel to one of the three switches 14 is switched; three current transformers 22 as part of a motor protection, one of which is one of the three leads to the motor windings T1-T3 is assigned so that in the motor windings T1-T3 flowing electrical currents can be measured without contact; one unit with the control 18th the triacs 16 and the switch contacts 14 , a motor protection release electronics 20 and a power supply for the two units 18th and 20 which have a DC voltage of 24 volts on the input side and an AC voltage of 230 volts on the input side into one for the voltage supply of the two units 18th and 20 implement suitable operating voltage.

1. 1. Einschalten des elektronischen Motorstarters, Anfahren des Motors:
   • Bei einem Einschaltvorgang schaltet die Ansteuerung 18 zunächst die Triacs 16 ein, so dass über diese die beim Anfahren des Motors auftretenden hohen Ströme von den drei Phasen L1-L3 in die Motorwicklungen T1-T3 fließen können.
   • Nach einer vorgegebenen Zeitdauer, die von verschiedenen Parametern wie beispielsweise dem Absinkverhalten der Ströme abhängen kann, schaltet die Ansteuerung 18 die Schaltkontakte bzw. Schalter 14 des Schützes 12 ein.
   • Wiederum nach einer vorgegebenen Zeitdauer schaltet dann die Ansteuerung 18 die Triacs 16 wieder aus, so dass die Ströme von den drei Phasen L1-L3 über die Schaltkontakte bzw. Schalter 14 des Schützes 12 fließen.
2. 2. Ausschalten des elektronischen Motorstarters, Abschalten des Motors:
   • Bei einem Ausschaltvorgang schaltet die Ansteuerung 18 zunächst wieder die Triacs 16 ein.
   • Nach einer vorgegebenen Zeitdauer, die von verschiedenen Parametern wie beispielsweise dem Absinkverhalten der Spannungen abhängen kann, schaltet die Ansteuerung 18 die Schaltkontakte bzw. Schalter 14 des Schützes 12 aus.
   • Wiederum nach einer vorgegebenen Zeitdauer schaltet dann die Ansteuerung 18 die Triacs 16 wieder aus.

The following is how the control works 18th explained, which can be implemented by a microprocessor or microcontroller and an operating program stored in a memory and executable by the microprocessor or microcontroller or by an ASIC (Application Specific Integrated Circuit) or (F) PGA ((Field) Programmable Gate Array):

1. 1. Switch on the electronic motor starter, start the motor:
   • When activated, the control switches 18th first the triacs 16 so that the high currents from the three phases that occur when starting the motor L1-L3 into the motor windings T1-T3 can flow.
   • After a predetermined period of time, which can depend on various parameters such as the sinking behavior of the currents, the control switches 18th the switch contacts or switches 14 the shooter 12th a.
   • The control then switches again after a predetermined period of time 18th the triacs 16 back out so the currents from the three phases L1-L3 via the switch contacts or switches 14 the shooter 12th flow.
2. 2. Switching off the electronic motor starter, switching off the motor:
   • The control switches when the device is switched off 18th first the triacs again 16 a.
   • After a predetermined period of time, which can depend on various parameters such as the drop behavior of the voltages, the control switches 18th the switch contacts or switches 14 the shooter 12th out.
   • The control then switches again after a predetermined period of time 18th the triacs 16 out again.

The one from the control 18th controlled switching operations of the triacs 16 and the switch contacts or switches 14 the shooter 12th cause the switch contacts or switches 14 switch almost without power and are therefore better protected against wear, for example by opening the switch contacts 14 Arcing occurring can be effectively prevented, causing the switch contacts 14 better protected against arc-related wear such as erosion etc. and by connecting the motor windings T1-T3 with the phases occurring high and the switch contacts 14 heavy currents can be avoided.

The function of the motor protection is explained below. The motor protection release electronics 20 continuously measures via the current transformers 22 the in the windings T1-T3 flowing currents and sends its switch-off signal to the control 18th as soon as the measured currents leave a specified nominal current range of the motor. The control 18th initiates the shutdown procedure described above in response to the shutdown signal. The motor protection release electronics 20 can, for example, as in the international patent application W02007 / 104733A2 be described.

In 2nd is a concrete implementation of the plug-in module according to the invention 10th in the open view and the contactor 12th on which the module 10th can be plugged on.

The contactor 12th is designed for mounting on a profile rail of a switch box or control cabinet and has one of its front side switch connections 36 for multiple phases or motor winding connections. In his headstock 38 are counter contacts 28 for the plug contacts 26 of the module 10th provided in corresponding recordings.

The module 10th includes a module base plate 24th with contacts for contacting the module plug contacts 26 with the corresponding contacts on the module electronics board 32 by an upper housing part 30th the module is protected from environmental influences. The module plug contacts 26 extend in two rows, as in 3rd is clearly visible down from the bottom plate 24th away and serve on the one hand for the electrical connection of the module 10th with the contactor 12th and on the other hand to fix the module 10th on the contactor 12th . To combine module 10th and contactor 12th simply become the module plug contacts 26 in the counter contacts 28 the shooter 12th plugged in as in the 3rd to 5 is shown by the dashed lines. Per switch or contact pair of contactors 12th is a plug contact pair on the base plate 24th of the module 10th intended. On the bottom plate 24th can also be a spigot 40 be provided (see 4th ) that the module 10th on the headstock 38 the shooter 12th aligns.

6 shows the contactor 12th with the attached module 10th . The contactor is now in this state 12th Retrofitted with protection against high currents during switch-on and switch-off processes as well as motor protection without the need for extensive wiring, which considerably simplifies the use of the module.

The present invention is particularly suitable for retrofitting contactors to extend the service life and, at the same time, to keep the wiring effort for connecting to the contactor as low as possible. The invention is particularly suitable for use with electronic motor starters. The protective function of the module can be further expanded by an integrated motor protection.

Reference list

10th

plug-on module

12th

Contactor

14

Switch contacts

16

Triacs

18th

Control of the triacs 16 and switch contacts 14

20

Motor protection tripping electronics

22

Power converter

24th

Module base plate

26

Module plug contacts

28

Contactor counter contacts

30th

Module housing upper part

32

Module electronics board

34

Power supply

36

Switching connections

38

Contactor head plate 12th

40

Cones

Claims (5)

Plug-in module (10) designed for retrofitting a contactor (12) - Semiconductor switches (16) which can be connected in parallel with switching contacts (14) of the contactor, - A control (18) for the semiconductor switch (16) which is designed to control the semiconductor switch (16) as a function of the control (18) of the contactor (12) during an on and / or off operation of the contactor (12) in such a way that switch the switching contacts (14) almost without power, and - An integrated motor protection circuit (20, 22) which has motor protection tripping electronics (20) and at least one current transformer (22) for contactless measurement of an electrical current, the tripping electronics (20) being designed continuously via the at least one current transformer (22 ) measure an electrical current without contact and send a switch-off signal to the control (18) to initiate a switch-off process when the measured current leaves a predetermined nominal current range. Module (10) after Claim 1 , characterized in that the semiconductor switches (16) are implemented by triacs (16) or thyristors connected to one another. Module (10) after Claim 1 or 2nd , characterized in that the control (18) is designed to - first close the semiconductor switches (16) during a switch-on process, then close the switch contacts (14) and then open the semiconductor switches (16), and / or - for one Switching off first to close the semiconductor switches (16), then to open the switch contacts (14) and then to open the semiconductor switches (16). Module (10) according to one of the preceding claims, characterized in that it has a housing with a base plate (24) which has contacts (26) with which the module (10) in corresponding counter contacts (28) of the contactor (12) can be attached to this. Contactor (12) with a head plate (38) and mating contacts (28) for mounting or contacting with plug contacts (26) of an attachable module (10) according to one of the preceding claims.

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