DE447846C - Electromagnetic switch - Google Patents

Description

The invention relates to electromagnetic self-switch, which at longer lasting and increasing current due to the thermal effect earlier, d. H. even at a lower level Switch off the current level. This is achieved according to the invention through the use of such substances in the path of the magnet's line of force, which have different magnetic properties at different temperatures

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Paramagnetic material is particularly suitable for these purposes. Magnetism and The permeability of these substances generally decreases with increasing temperature, but there are certain hard types of steel or iron alloys, for example with an addition of copper, which initially magnetizes with increasing temperature increases until it reaches its maximum level after a certain temperature limit has been exceeded and only then quickly falls off.

The change in magnetism and permeability is already about to trigger Circuit breakers have been used. In the case of the known versions, the one in the cold States or, if there is little heating, the magnetic force, regardless of the level, represents a counterforce for a triggering means and keeps the contacts in the switched-on position fixed. However, as soon as heating above the above-mentioned temperature limit has occurred with a high rise in current, it disappears the magnetism is complete, so the counterforce of the magnet is extinguished, and the switch speaks under the influence the mechanical release force.

In contrast, the essence of the invention consists in the increase in permeability and magnetism in the first temperature interval for an amplification of the magnetic force in such a way that, in the event of a prolonged overcurrent, a faster one and earlier release occurred. So while at the known facilities through complete disappearance of the magnetic force tripping in a very specific Moment occurs, the invention

objects a temporary increase in sensitivity by increasing the magnetic force of the self-switch achieved.

The invention is explained with reference to the drawing. In the embodiment according to Fig. I, α is a magnetic coil and b is a magnetic core influenced by the magnetic coil. If this magnetic core is made of a paramagnetic material, the magnetism is changed as the current rises due to the heating in such a way that the switch responds earlier if the current continues for a longer period of time.

The device according to Fig. 2 is also a magnetic core b made of paramagnetic material, which is under the influence of the magnetic coil α. A special part c and a spring d, both of paramagnetic material, are provided in the magnetic circuit. In the event of an overcurrent and the resulting heating, both the magnetic force and the counterforce of the spring d change, so that the switch is triggered earlier. According to Fig. 3, the earlier triggering of the switch is achieved as a result of the heating through the change in the air gap between the core and the armature. The appropriately U-shaped metal piece e made of bimetal is arranged between the movable magnetic core b and the fixed magnetic core c. When heated, the air gap is reduced by the MetaHstück e stretches.

3'5 Fig. 4 shows an embodiment of the subject matter of the invention with a double-T-shaped magnetic core. The iron path is broken through on both sides in the outer leg. On the one hand, the air gap / remains, on the other hand it is bridged by an insertion g made of paramagnetic material, which particularly shows the property of showing increasing permeability when heated up to a certain maximum limit. When heated, the permeability of the insert g increases. Therefore, a larger number of lines of force go through this part of the magnet, while the number of lines of force in the other leg with the air gap f is lower. The higher magnetization of one part can cause the switch to respond earlier.

In Fig. 5 a device is then shown in which the spring h, which pulls the release lever i back, is influenced by the magnetic core h . The spring h is attached on the one hand to the release lever i and on the other hand to the lever I rotatably mounted at point k . The magnetic core b rests on the lever Z, so that the spring h receives a certain tension and thereby the release lever i receives a certain retraction force. If the magnetic core b, which consists of paramagnetic material, is raised as the current through the coil α rises, the lever I and thus also the spring h are relieved. This also reduces the retraction force of the release lever i and triggers the switch earlier if the core b hits the release lever i in the event of an overcurrent, as this now requires less force than if the previous tension of the return spring h were present.

Claims (5)

Patent claims: i. Electromagnetic self-switch, characterized in that part of the magnetic circuit consists of paramagnetic material, the magnetism of which when heated due to an increase in the Current increases by increasing the permeability and therefore with a longer duration Overcurrent causes earlier tripping. 2. Circuit breaker according to claim 1, characterized by an air gap in the magnetic circles, which are caused by paramagnetic material only after long lasting Heating is bridged. 3. circuit breaker according to claim 1 and 2, . characterized in that the paramagnetic material when heated as a result Expansion (bimetal) reduces the air gap and thereby the overall magnetism elevated. 4. circuit breaker according to claim 1 or the dependent claims, characterized in that that part of the magnetic circuit is so subject to heating that the magnetism of this part disappears and the lines of force thereby diverted that a faster tripping is effected. 5. Circuit breaker according to claim 1 or the dependent claims, characterized in that that the return spring, which holds the mechanism in the on position, with increasing magnetic force their spring force is reduced and the release is accelerated. For this purpose ι sheet of drawings.