DE1024609B - Device for synchronous switching on of high currents - Google Patents

Description

GERMAN

The invention relates to a device for synchronously switching on high currents in a provided Moment within a period or half period of the alternating current, especially during of the current zero crossing. The known devices that serve this purpose have one relatively large degree of inaccuracy, since the triggering of the switching process more or less the inherent inertia of the switch parts, which have to be accelerated when the switch is operated, is dependent.

In order to avoid the loss of time that results from the acceleration of moving parts, it is already known to switch on an auxiliary circuit at a predetermined instant to be carried out by a synchronously rotating contact disc. This lies with one of the switching preparatory switch in series, after its closing then over at the desired time The contact disc sends a current through a relay, which in turn is a main circuit closes. Apart from the fact that it is difficult to switch very high currents with the aid of a relay, it provides the magnetic inertia of the relay winding also represents an undesirable delay, which is caused by the Contact disk practically eliminates the advantage of synchronous activation achieved in itself. You will therefore, in the case of such an indirect circuit through the contact disk, no high time accuracy can be obtained.

This deficiency can in the device according to the invention, which is also from a synchronously rotating Contact disc and a switch located in series with this makes use of it Actuation of the switch-on process is prepared, does not occur. According to the invention are the contact discs and the switch immediately in the high current circuit, e.g. B. a switch testing system, arranged and the contact disc is bridged by an auxiliary switch, which after switching on the power is closed by the contact disc.

The high current is switched here directly through the contact disc so that there is no temporal Delay can occur. Switching on high currents can also be done easily from the contact disk be taken over, since the current conduction is only of a short period of time until the it bridging auxiliary switch is closed. One achieves with the device according to the invention all cases that ζ. B. in switch test systems, which require very precise compliance with the instant of switch-on arrives, the high current is switched on immediately in its zero crossing when the Occurrence cities DC link should be avoided.

Device for synchronous switching on of high currents

Applicant:

LICENTIA Patent-Verwaltungs-G.m.b. H., Hamburg 36, Hohe Bleichen 22

Dr.-Ing. Rudolf Gärtner, Kassel-W "

and Dr. phil. Karl-Heinz Voigt, Kassel, have been named as the inventor

The auxiliary switch can be formed by a self-holding current-dependent relay or by power gates that remain conductive after ignition. The control of such an auxiliary switch in Depending on the phase of the alternating current, for example, via one of the to be switched Current-excited current transformers take place, with a suitable choice of inductances an approximately desired one Phase shift can be established.

The invention is illustrated in the drawing using two exemplary embodiments.

In Fig. 1, the alternating current network N feeds a consumer V, which is switched on by the contact disk /, which rotates synchronously with the voltage curve of the network. It should have a large centrifugal mass in order to achieve a uniformity of rotation. A metal covering 3 is attached to its circumference, which periodically comes into conductive contact with a slip ring 5 ″. Conversely, the disk / could also be made of metal and carry an insulated sector.

Along the circumference of the disc / slides a powerful roller R or a contact loop connected to the network. The current closes when switched on via the roller R, the lining 3, the slip ring S, a brush B and a series switch 1 as well as via the consumer V. So that this precise switch can no longer switch off during the further cycle, it is bypassed shortly afterwards switching on, while the roller R is still in contact with the covering 3, by means of an auxiliary switch 2.

The shaft W, on which the disk / and the slip ring Λ ″ are attached, is driven in a manner known per se as a function of the mains voltage. At any point in time, that is usually when

709 880/327

the roller R is not yet in contact, switch 1 switches on. In the example shown, it supplies voltage to the covering 3, but it could also be in front of the roller R and switch it to voltage. Its accuracy, due to the spread of the switching time, only needs to be within a half-wave. The contact is now made very precisely at the desired moment between the roller R and the covering 3, because an exact synchronous movement is given and an inertial mass does not have to be set in motion first if one wants to switch. The series switch 1 can also supply the disc / the voltage in a desired half-wave, which z. B. as known, can be achieved by mechanical coupling with a further switching element. A switching element rotating with the disk S can also block the switching on of the switch 1 as long as the roller R is in contact with the segment 3.

Fig. 2 shows an even simpler embodiment of the synchronous switch according to the invention. A switching element is replaced here by a rotating sling in the form of a strong metal band 7 with a weight G at one end. The other end of the metal band is attached to the disc /, which in turn is driven synchronously with the tension of the network Λ '. This end of the metal strip has a conductive connection via a slip ring S to a network pole. The disk / is driven by the shaft W via a slip clutch, not shown. Before switching on, the weight G is thrown outward by the centrifugal force and synchronously moved past the counter contact 8 in the direction of the circular arrow 9.

Switching on takes place as follows: Shortly after the flyweight G has been thrown past the mating contact 8, z. B. by a cam on the slip ring S, the mating contact 8 is moved into a position 8 '. The weight (7 flies towards the mating contact 8 'and loops the metal band 7 around it, as shown in FIG. 3. This places the consumer V on the network. The contact pressure is strong rotates before the slip clutch disengages it, the weight now assumes the dashed position G ' . To prevent the weight from looping its metal band 7 around the contact 8' several times, it is expediently made with a larger diameter is to be moved, it is recommended that it be designed as a hollow bolt.

For test purposes it is sometimes desirable to determine in advance any point in the half-cycle at which the switch-on is to take place. This point in time can be reached by photoelectrically monitoring the weight circulation and then adjusting the counter contact 8 accordingly along the arrows a, b. Instead of the weight G , the band 7 can also throw a hook which hugs the contact 8 '.

Claims (2)

PATENT CLAIMS: 1. Device for synchronous switching on of high currents with a synchronously circulating Contact disc and a switch located in series with this, by actuating the switch Switching on is prepared, characterized in that the contact disc and the Switch (1) directly in the high-current circuit, e.g. B. a switch test system, are arranged and the contact disc is bridged by an auxiliary switch (2), which is activated after the Current is closed through the contact disc. 2. Device according to claim 1, characterized by a blockage between the contact disk and preparatory switch (1) which prevents the switch (1) from being actuated as long as the metal coating (3) of the contact disk touches the loop contact [R). Considered publications:
German patent specifications No. 212 303, 222 886,
888 1 sheet of drawings © 709 880/327 2.