WO2004047137A1

WO2004047137A1 - Auxiliary release device for motor protection switches

Info

Publication number: WO2004047137A1
Application number: PCT/EP2003/012867
Authority: WO
Inventors: Wolfgang Esser
Original assignee: Moeller Gmbh
Priority date: 2002-11-20
Filing date: 2003-11-18
Publication date: 2004-06-03
Also published as: DE10254038A1

Abstract

The invention relates to an auxiliary release device (12) whose housing (14) can be arranged in an adjacent manner in relation to the switch housing (4) of the motor protection switch (2), comprising first connecting terminals (21) for application of an electric variable which is to be monitored and an electromagnet system whose armature (46) actively cooperates with a pawl system on the switch lock (32) of the motor protection switch (2) for release purposes. An electronic evaluation device (42) is provided in the auxiliary release device (12) and is connected on the input side to the first connecting terminals and connected on the output side to the magnetic coil (44) of the electromagnet system. The variable to be monitored is provided by a thermistor (40) which is connected to an motor (38) which is served via the motor protection switch (2).

Description

Auxiliary release for motor protection switches

Technical field

The invention relates to an auxiliary release for motor protection switches, with a trigger housing which can be attached to the switch housing of a motor protection switch, the first connecting terminals for applying an electrical variable to be monitored, and an electromagnet system which has a magnet coil and a magnet armature, the magnet armature having a trigger housing attached to the switch housing corresponding passage openings of the trigger housing and of the switch housing at least indirectly reach the latching system connected to the switch lock of the motor protection switch,

State of the art

Motor protection switches are designed with multiple poles according to document DE 35 45 930 A1 and have a corresponding number of main contacts. The main contacts are closed or opened via a key switch either by hand or by a motor drive. In the event of a persistent overload or a short-circuit current, the bimetallic or magnetic triggers respond, which in turn release the latching mechanism of the key switch and thus trigger the key switch, which leads to the opening of the main contacts.

An auxiliary current release for such a motor protection switch is known from the document DE 100 04 597 A1, the auxiliary current release acting either as a shunt release or as an undervoltage release. The auxiliary current release is housed in a release housing that can be attached to the side of the switch housing of the motor protection switch. The triggering signal is fed to the auxiliary current release via two connection terminals, between which the solenoid of an electromagnet and an auxiliary switch are arranged. The spring-loaded magnet armature of the electromagnet actuates the auxiliary switch and a release lever in the event of tripping. The Release lever extends with one arm through the release housing and the switch housing to the latching system of the switch lock of the motor protection switch. In the event of a trip, the release lever releases the key switch, whereupon it switches to the released state and opens the main contacts of the motor protection switch.

It is generally known, for example according to document DE 93 02 254 U1, to connect motor protection switches with signaling devices which signal a short-circuit or overload release via auxiliary switches.

From the document DE 37 28 197 A1, an electronic motor protection relay is known which emits a trigger signal in the event of overloads which can lead to the motor being protected and being overheated. This trigger signal is used to control a contactor that switches off the motor. The motor protection relay has an electronic evaluation arrangement, to which measuring signals proportional to the phase currents are supplied on the one hand via current transformers and on the other hand is connected to a thermistor arranged in the motor. The evaluation arrangement checks the incoming signals for short circuit, overload asymmetry, phase failure and temperature overshoot. If criteria defined by the signals are exceeded, a trigger signal is issued to switch off the contactor.

Presentation of the invention

The invention has for its object to improve protection for motorized systems.

By evaluating an electrical quantity that is supplied by a thermistor connected to the motor-operated system to be switched and protected, and by switching off the motor, which is caused by a critical temperature being exceeded within the motor-operated system, it is connected to the auxiliary release Motor protection switch provided a protective function, which also exists in addition to the usual protective functions based on the evaluation of the motor current. The thermistor is installed either in the motor itself or within the driven system, for example at a temperature-critical bearing point. The auxiliary trigger according to the invention is in combination with a Conventional motor protection switches are a convenient alternative to the known combination of a contactor and an electronic motor protection relay with a thermistor monitoring function. With the invention, an effective combination of the thermistor protection function with the isolator and main switch properties, such as the lockability of the handle of the motor protection switch, is made possible.

A first advantageous development of the invention consists in the fact that the magnetic armature itself triggers the switching lock. Here, the magnet armature acts either on a release element, e.g. through release openings of the release housing and the switch housing. in the form of a trigger shaft or a trigger slide, or on the latching mechanism of the switch lock arranged in the motor protection switch.

A second advantageous development of the invention consists in the fact that the magnetic armature of the auxiliary release indirectly triggers the switching lock via a transmission element. Here, the transmission element either acts on a triggering element via passage openings, e.g. in the form of a trigger shaft or a trigger slide, or on the latching mechanism of the key switch.

The trigger housing is expediently to be connected laterally to the switch housing.

Finally, further developments of the invention consist in the fact that an auxiliary relay and / or a lighting element is connected to the evaluation arrangement. In the first case, an overtemperature occurring on the motor is signaled via the auxiliary relay contact as a remote electrical signal and in the second case as an optical signal on site.

Brief description of the drawings

Further details and advantages of the invention result from the following exemplary embodiments explained with reference to figures. Show it Figure 1: in a spatially separated representation, an embodiment of the auxiliary release according to the invention and an associated motor protection switch;

Figure 2: a first schematic diagram of a combination of motor protection switch and auxiliary release;

Figure 3: a second schematic diagram of a combination of motor protection switch and auxiliary release.

Best way to carry out the invention

1 shows a conventional three-pole motor protection switch 2 with a switch housing 4, a rotatable handle 6 mounted on the front for switching on and off, main connections 8 on the input side for feed lines and main connections 10 on the output side for connecting lines to a motor as a consumer. Furthermore, an auxiliary release 12 is shown with a release housing 14, a pair of first connection terminals 21 for an electrical variable to be monitored and a pair of second connection terminals 22 for a supply voltage. With the aid of connecting means, of which only two locking hooks 15 formed in the rear area of the trigger housing 14 can be seen in FIG. 1, the auxiliary trigger 12 can be connected laterally to the motor protection switch 2. A first passage opening 16 is also formed on the trigger housing 14, through which an extension 18 extends which, when the auxiliary trigger 12 is connected to the motor protection switch 2, can trigger the switching lock arranged in the switch housing 4. An exit window 24 for a lighting element is also provided on the trigger housing 14.

With the help of the schematic representation of FIG. 2, further features of the auxiliary release 12 and the function thereof in combination with the motor protection switch 2 are to be explained below. Within the switch housing 4, there is a separable connection for all three poles from the feed-in main connections 8 via main contacts 26 and from these a connection via thermally delayed overload releases 28 and electromagnetic short-circuit releases 30 to the consumer-side main connections 10. The main contacts 26 are made via the switch lock 32 either opened and closed by means of the handle 6 or opened automatically when the current flowing through the main contacts 26 exceeds adjustable error criteria. The overload releases 28 and the short-circuit releases 30 When the set error criteria are exceeded, a release slide 34 mounted in the switch housing 4 engages in a latching system 36 connected to the switch lock 32, the release slide 34 triggering the switch lock 32 by releasing the latching system 36, whereby the main contacts 26 automatically be opened.

The main connections 10 on the consumer side are connected to a motor 38, in the stator of which a thermistor 40 is embedded as a thermal sensor. The electrical quantity (current, voltage or resistance) supplied by the thermistor 40 is led via the first connection terminals 21 to an electronic evaluation arrangement 42 in the auxiliary release 12. The evaluation arrangement 42 is supplied with voltage via the second connection terminals 22. The electrical variable supplied by the thermistor 40, for example the resistance value, is continuously detected via the evaluation arrangement 42. If this electrical variable shows a significant change as a result of inadmissible heating of the motor 38, the evaluation arrangement 42 excites a magnet coil 44 which belongs to an electromagnet system, of which the movable magnet armature 46 is also shown in FIG. 2. The magnet armature 46 engages with its push-shaped extension 18 through the first passage opening 16 in the trigger housing 14 and through an opposite second passage opening 17 in the switch housing 4. By means of the energized magnet coil 44, the magnet armature 46 becomes so far into the interior of the magnet coil 44 against a return spring (not shown) pulled (to the right in FIG. 2) that the extension 18, with its free end, displaces the trigger slide 34 in such a way that the switching lock 32 is triggered and thus the motor 38 is switched off via the subsequent opening of the main contacts 26. The auxiliary release 12 is also provided with a lighting element 48, preferably with an LED element. After the limit value exceeded by the quantity supplied by thermistor 40, the lighting element 48 is opened by the evaluation arrangement 42, so that the excess triggering of the permissible temperature in the motor 38 is signaled optically on the auxiliary trigger 12.

Fig. 3 shows the combination of the motor protection switch 2 with an auxiliary release 13 of another embodiment. Only the features and properties that differ from the embodiment from FIG. 2 are described below. In this case, reference numerals used from FIG. 2 are adopted if they relate to function elements which have essentially the same effect. When the magnet coil 44 is excited by the evaluation arrangement 42, a magnet armature 47 is set against a reset applied spring force, so that it performs a movement to the right according to FIG. 3. As a result of this movement, the magnet armature 47 hits a first lever arm 51 of a double-arm transmission element 50 with a push-shaped extension 19, which is pivotably mounted in the trigger housing 14. The transmission member 50 extends with its second lever arm 52 through the lateral passage openings 16 and 17 in the trigger housing 14 or switch housing 4. The magnet 50, which is acted upon magnetically, causes the transmission member 50 to be pivoted counterclockwise as far as shown in FIG. 3, that the second lever arm 52 strikes the latching system 36 and thereby triggers the switching lock 32. Here, too, when the temperature detected by the thermistor 40 in the stator of the motor 38 exceeds the permissible limit temperature, the main contacts 26 of the motor protection switch 2 are automatically opened and the motor 38 is thus disconnected from the supply voltage. At the same time, the evaluation coil 42 excites the relay coil 54 of an auxiliary relay arranged in the auxiliary release 12, as a result of which the associated relay contact 56 is actuated. When the motor 38 is switched off, signal lines connected to the third connecting terminals 23 connected to the relay contact 56 can be used to report that the permissible motor temperature has been exceeded.

The combinations of motor protection switch 2 and auxiliary releases 12 and 13 have the usual protection options against overload and short circuit and offer additional protection by evaluating the motor temperature detected directly by thermistor 40. The auxiliary switch 12 according to FIG. 2 can also be equipped with an auxiliary relay 54, 56 according to FIG. 3. Conversely, the auxiliary switch 13 according to FIG. 3 can additionally be equipped with a lighting element 48 according to FIG. 2.

The invention is not limited to the application described above. For example, the electrical variable detected by the auxiliary release 12 or 13 can be taken from a thermistor, which is attached to a critical point within the machine or system operated by the motor 38, in particular to a bearing threatened by hot running.

Claims

Expectations

1. Auxiliary release for motor protection switch, comprising - a mountable to the switch housing (4) of a motor protection switch (2)

Trigger housing (14),

- first connection terminals (21) for applying an electrical variable to be monitored,

- An electromagnet system which has a magnet coil (44) and a magnet armature (46; 47), the magnet armature (46; 47) when the trigger housing (14) is attached to the switch housing (4) via corresponding passage openings (16; 17) in the trigger housing (14) and the switch housing (4) extends at least indirectly to the latching system (36) connected to the switch lock (32) of the motor protection switch (2), characterized by

- second connection terminals (22) for applying a supply voltage,

- An electronic evaluation arrangement (42) which is connected on the input side to the first connection terminals (21), on the supply side by the second connection terminals (22) and on the output side by the magnet coil (44), the size to be monitored being supplied by a thermistor (40) is connected to a system operated by a motor (38) and supplied via the motor protection switch (2).

2. Auxiliary release according to claim 1, characterized in that the magnetic armature (46) passes through the passage opening (16) of the release housing (14).

3. Auxiliary release according to claim 1, characterized in that a movable transmission member (50) is mounted in the release housing (14), which is operatively connected on the one hand to the magnet armature (47) and on the other hand through the passage opening (16) of the release housing (14) occurs.

4. Auxiliary release according to one of the preceding claims, characterized in that the magnet armature (46; 47) is formed in a push-button shape.

5. Auxiliary release according to one of the preceding claims, characterized in that the trigger housing (14) can be connected laterally to the switch housing (4).

6. Auxiliary release according to one of the preceding claims, characterized by an auxiliary relay (54, 56) which is controlled on the input side by the evaluation arrangement (42) and is connected on the output side to third connecting terminals (23).

7. Auxiliary release according to one of the preceding claims, characterized by a lighting element (48) controlled by the evaluation arrangement (42).