DE1263138B - Switching arrangement for the synchronous switch-off of alternating currents - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN JiflTTWl · PATENT OFFICE

EDITORIAL

Int. Cl .:

Number:
File number:
Registration date:
Display day:

HOIb

German class: 21c - 35/07

V29906VIIId / 21c
December 11, 1965
March 14, 1968

The invention relates to a single-pole or multi-pole switching arrangement for synchronous disconnection of alternating currents with a magnetically controlled contact arrangement working under vacuum, in the case of the one caused by the main current to achieve the desired synchronous contact opening pulsating excitation and an excitation independent thereof are provided.

Attempts have already been made to achieve synchronous shutdown using purely mechanical means. the However, the tolerances occurring here are so large that only a very large one for high-voltage switches yet, for low-voltage switchgear, however, an effort that is no longer justifiable is an approximation synchronous opening of the contacts can be achieved.

In the case of a contact arrangement operating under normal atmospheric conditions, the Successful synchronous disconnection is a prerequisite that after the contacts have opened the Contact spacing or the electrical strength in the contact gap increases very quickly, by which in extreme cases in the case of inductive load, immediately withstand the oscillating voltage to at least the maximum value to be able to. In order to keep this minimum contact distance, which can be achieved within a very short time, smaller It is known to be able to place the contact point in a medium with a higher dielectric strength from the outset ζ. B. to be arranged in a vacuum. In addition to the advantage of a much smaller contact opening required The contacts can open due to the very high electrical strength in a vacuum can also be permitted shortly before the current zero crossing. This reduces the effort required still considerable.

Switching arrangements for synchronously switching off alternating currents have already become known, in which a mechanical or magnetically controlled contact arrangement working under vacuum is present. is seen and in which the spring-loaded movable contact piece when switching off is kept closed by a magnet excited by the main current until, as a result of the the next current zero crossing of the main current, the excitation goes to zero and the movable one Contact piece opens as a result of the spring forces.

In a known vacuum switch of this type, a switching lever that is mechanically controlled from the outside and carries the resiliently mounted contact element is provided. The contact element itself consists of two contact pieces which switch one after the other, of which the contact switching arrangement which opens last when switching off is used for synchronous switching off
of alternating currents

Applicant:

VEB Elektro-Apparate-Werke Berlin-Treptow,

Berlin-Treptow, Hoffmannstr. 15-26

Named as inventor:

Dr.-Ing. Günter Burkhard,

Eckehard Gebauer, Berlin-Baumschulenweg

piece of a magnet that is constantly excited by the main current against the magnet that grows when it is switched off The spring tension of the contact piece is kept closed until the current drops to zero or almost zero will. The mechanical control of the gear lever from the outside, which in itself is not one represents a justifiable high effort, but is also disadvantageous insofar as the inevitably occurring Tolerances large inaccuracies occur in the switching process. These inaccuracies will be by the resilient fastening of the two contact pieces on the shift lever still enlarged and thus require a relatively large contact gap and also question the synchronous shutdown. Another requirement for synchronous shutdown is in this arrangement that the externally mechanically controlled movement of the shift lever always runs constantly, which makes this arrangement even more complex.

Another known switching device that can be used for synchronous shutdown exists from a large number of magnetically movable, rotatably mounted switching bridges with double interruption, in a closed, with an extinguishing medium such. B. compressed air, filled capsule are arranged. the Switching bridges are held in the switch-on position by a restoring force and are only activated when required Switch-off moment opened by energizing the intended magnetic circuit, thus interrupting the circuit and close again immediately under the influence of the restoring force after termination of the Switch-off command. The final disconnection is carried out by a special disconnector.

809 518/517

3 4

Disadvantages arise for this arrangement before switching arrangement for synchronous switching off of everything in that alternating currents are to be created for synchronous switching off, in which any uncontrollable influence of friction are required under additional control elements for the magnetic circuit, which ultimately become movable due to their tolerances Parts and the mechanical control synchronous shutdown into question. The 5 tion of the contact movement from the outside avoids bearing friction of the rotatably mounted switching bridges, and in which only the pure contact point in which all would have to open at the same time, is arranged in a vacuum chamber.
Uncertainty factor for synchronous opening still "This object is achieved by the fact that erfuvwessentially increased. This arrangement also requires the contact arrangement in a necessary working air gaps due to the existing air gaps in addition to the fixed and a working air gap and the one at the end Ferromagnetic material consist - switching bridges attacking restoring force, which is arranged in the closed magnetic circuit and opening must be overcome, a relatively known, large magnetic circuit in the vacuum chamber, arranged resilient, establishing the contact

In another known synchronous switch 15 metal tongues made of ferromagnetic material serves the armature of the magnetic circuit as a carrier that stands. The fixed air gap of the closed magnetic switch bridges for the movable contacts, while the circle serves as a galvanic separation of the fixed contacts are designed to be resilient. These two poles of the switching arrangement. The aim of this arrangement is to save, in particular, the independent excitation of the magnetic circuit of the movable contact switching bridges designed as pressure springs for opening the movable metal tongue. An arrangement of these jumpers closed and kept in the switched-on state, or the entire circuit under vacuum should. This independent excitation is superimposed after closing due to the separation of the main circuit of the contacts, an excitation caused by the main current and the magnetic circuit not pulsating with justifiable means so that to be reached. In addition, when the independent excitation is switched off, the pulse movement of the excitation serving as the carrier of the switching bridges only has to be accelerated until the armature is short. Such an increase in the moving masses before the zero crossing of the main flow is, however, for one and then allows them to open synchronously,
synchronous opening of the movable contacts is not the one afflicted with very small mass and desirable in their. 30 movement no friction and during the

It is furthermore a vacuum switch with a known lifespan, practically none of the accuracy become, in which a the movable contact piece of the synchronous disconnection impairing load-bearing, rotatably mounted two-armed gear lever, which is subject to aging, enables the is provided by a spring in the switch-on-synchronous switch-off. The training as practical is held. The free end of the shift lever 35 in almost exclusively ferromagnetic material stands with a lever arm of a further, also closed magnetic circuit allows a small construction to be rotated The two-armed lever mounted on bearings also works with those required for larger currents link. Contact forces act on this second lever. Advantages also result from further spring in the sense of the opening of the shift lever that only the metal tongue in a vacuum and two independent magnet chambers separated from each other are arranged.

systems, one of which is from the main stream and in a further development of the invention for generation

the other by an excitation proportional to the main current that can be switched on and off at random

auxiliary current is excited, in the sense of closing the main circuit of the saturation transformer

the shift lever in such a way that when you open the seen. The excitation proportional to the main current

Auxiliary circuit that acts on the second lever 45 can also by means of a bridge or two-way circuit

Spring force is sufficient to be rectified at the zero crossing of the. For independent excitement

The main current of the switch lever against which it is in is either direct voltage or equal-

to open the switch-on holding spring. directed, preferably compared to the main stream

This arrangement also does not avoid the alternating voltage, which is mechanically phase-shifted by 90 °.

niche control from the outside and is also seen quite 50.

expensive and with considerable disadvantages. It is known that under certain advance sun there are settlements for generating the switch-on movement or, in the event of a fault, in a vacuum and two separate E-switches can cause overvoltages for synchronization. To the directions required. Switching on is caused by the harmful effects of these surges The effect of the spring acting on the gearshift lever is to avoid this, the fixed air gap can act as one of the However, considerable bruises occur due to the defined clearance that is used for overvoltage protection are designed to be of great disadvantage, especially in vacuum switches, or are made of one material. These bruises are to be filled in on the masses of the two-dependent resistance, which are so out-of-arms traced back trained shift lever. are placed that when a certain limit is exceeded In addition, such an arrangement is also with 60 value of the overvoltage, the switching path is short-term inaccuracies due to which it is connected with tolerance.

zen afflicted movable two-armed lever, which The invention is to be used below in an embodiment

by friction in the bearing points are still much more detailed management example. In the

is enlarged, tainted, which shows a synchronous drawing

Shutdown at zero crossing is in question. 65 Fig. 1 the schematic representation of a single

The arrangement of the two-pole switching arrangement is also complex,

separate magnet arrangements. F i g. 2 the graphic representation of the switching

The invention is based on the object of a process.

The two magnet halves 1, 2 form a closed magnetic circuit with the fixed air gap 3 made of insulating material and the resilient metal tongue 6 made of ferromagnetic material. The supply line 4 and the discharge line 5 of the main circuit to be switched are connected to the two magnet halves 1, 2. The electrically conductive attached to the magnet half 2, the contact making metal tongue 6 is located in a vacuum chamber 7, the z. B. can be made of glass and with the magnet halves 1, 2 vacuum-tight ζ. B. is connected by glazing. The magnet half 1 carries the winding 8 for the constant excitation 0 "which is independent of the main current / and the magnet half 2 carries the winding 9 for the excitation 6> _{f which is} proportional to the main current 7. The current transformer 10 is located in the main circuit, from which a pulsating current proportional to the main current for the winding 9 is taken off by means of the rectifier 11.

When the independent constant excitation 0 _{U is switched on} , the generated magnetic flux Φ _α causes the metal tongue 6 to be attracted, which closes the main circuit. When the main circuit is closed, the current transformer 10 in conjunction with the rectifiers 11 in the winding 9 produces a pulsating excitation Θι proportional to the main current. This pulsating excitation 0, ·, which causes the magnetic flux Φ, -, is superimposed on the independent excitation 0 “to form the resulting excitation 0 _res , which in turn results in the resulting magnetic flux _{τ τβ5} .

When switching off the independent excitation 0 "at any time, the metal tongue 6 is caused only by the main current J proportional pulsating excitation 0 _(· magnetic flux _φ ι so long held in the on-position until the continuous zero pulsating excitation _0; or the corresponding magnetic flux Φ, -not longer sufficient to keep the resilient metal tongue 6 in the on-position. in a corresponding value from the pulsating excitation & _t the metal tongue 6 springs back into their disconnected position and opens when suitably dimensioning the main circuit shortly before or . in the current zero crossing.

The graphical representation of the switching process in Fig. 2 shows the individual acting on the magnetic circuit excitations 0 ", 0 _t, and the resulting excitation & _res and the distance traveled by the metal tongue 6 path s as a function of time t. Furthermore, the excitation & _{ab is} shown, in which the metal tongue 6 springs into the switched-off position. The time of the switch-on process E, E ' and the switch-off process A, A' can also be taken from the graphic representation. At χ the contact is open and at x 'it is closed.

Claims (4)

Patent claims: 1. Single or multi-pole switching arrangement for synchronous switching off of alternating currents with a working under vacuum, magnetically controlled contact arrangement, in which a pulsating excitation caused by the main current and an excitation independent thereof are provided to achieve the desired synchronous contact opening, characterized in that the contact arrangement is arranged in a closed magnetic circuit containing a fixed air gap (3) and a working air gap (5) and consisting exclusively of ferromagnetic material, with resilient metal tongues (6) made of ferromagnetic material, known per se, arranged in the vacuum chamber (7) and making the contact , whereby the metal tongues (6) are closed by the independent excitation (0 ") and kept in this state, during this excitation (0") a pulsating excitation caused by the current is superimposed in such a way that after the independent excitation is switched off (0 _a ) the superimposed, from the head The pulsating excitation caused by the current (J) _{(0 (} )) holds the movable contact tongue (6) only until shortly before the zero crossing of the main current and then allows it to open synchronously. 2. Switching arrangement according to claim 1, characterized in that for generating a dem Excitation proportional to the main current, a saturation converter located in the main circuit is provided is. 3. Switching arrangement according to claim 1 or 2, characterized in that the main stream proportional excitation from the main current by means of a bridge or two-way circuit is rectified and that for the independent excitation direct voltage or rectified, AC voltage, which is phase-shifted by 90 °, is provided with respect to the main current is. 4. Switching arrangement according to claim 1, characterized in that the provided in the magnetic circuit Fixed air gap (3) as one of the - Defined air gap serving for voltage protection is formed or with a material that is voltage-dependent Resistance is filled, which leads to a short circuit of the switching path when a certain value of the overvoltage is exceeded. Considered publications:
German Patent Nos. 909 728, 912597, 914145, 937422. 1 sheet of drawings 809 518/517 3.68 © Bundesdruckerei Berlin