DE1212188B - Electrodynamic high-performance quick switch - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

HOIh

German class: 21c-35/07

Number: 1212188

File number: U 9303 VIII d / 21 c

Filing date: October 1, 1962

Opening day: March 10, 1966

The invention relates to an electrodynamic high-performance high-speed switch for arbitrary circuit interruption regardless of the current strength.

For many industrial and research facilities, the actuation of fast acting switches is for interruption a circuit carrying electrical energy is required. For example, in Plasma research reactors of the stellarator class, in which a strong energy source is used to an ohmic heating circuit with high voltages and currents of up to 1000 amperes and above to excite during predetermined times, after the time interval has elapsed, the circuit with a Switch are interrupted, which the energy source in a very short time from the ohmic Heater winding switches off.

Conventional mechanical or magnetically operated switches have so far proven to interrupt electrical circuits including the aforementioned high-performance circuits for ohmic heating as have not proven satisfactory as they require expensive maintenance. For example, has such switches are designed for 115 or 120 volts; when separating their contacts, the performs the contacts flowing electrical energy to arcing and to scorching and melting phenomena at the contacts. This has also caused ionization of the air around the contacts, as well as other effects, which have led to the fact that the contacts still carry current even after the separation. These Switches were therefore also slow in their switching action. Also need the known switches relatively complicated, expensive or failure-prone electronic components or relatively expensive, complicated or dangerous explosive parts.

It is already an electrodynamic quick disconnect device for limiting and disconnecting of overcurrents and short-circuit currents, d. H. as overcurrent, especially short-circuit current protection, known, in which in the circuit to be switched, a current conductor is provided as a target interruption point is, which is under the influence of a magnetic winding such that by the interaction the magnetic field of the winding with the current in the interrupting conductor is a mechanical one Force is exerted on this. In the known arrangement, which, as I said, an overcurrent protection switch represents, the arrangement is made so that the magnet winding is electrically in the to be switched main circuit itself is arranged, namely the interrupting current conductor Electrodynamic high-performance quick switch

Applicant:

United States Atomic Energy Commission,

Washington, D. C. (V. St. A.)

Representative:

Dipl.-Ing. C. Wallach, Dipl.-Ing. G. Koch
and Dr. T. Haibach, patent attorneys,
Munich 2, Kaufingerstr. 8th

Named as inventor:

Max Bender,

Frank Kenneth Bennett, Trenton, N. J .;

Arthur Frank Kuckes, Princeton, N. J. (V. St. A.)

Claimed priority:
V. St. v. America 6 December 1961
(157 607)

and the magnet winding in series with one another in the power circuit to be switched. That with the magnetic field of the magnet winding interacting with the main current in the interrupting conductor, and thus also the mechanical forces occurring as a result of this interaction, thus depend on the main current flowing in the circuit to be switched. The interrupting conductor must therefore in the known arrangement be designed with sufficient mechanical strength that it is in the range of permissible high-power currents withstands these interaction forces. In the event of a sudden increase in the current (Overcurrent or short-circuit current) a point is reached at which the interaction force the Strength of the predetermined breaking points of the interrupting current conductor (which is also caused by the increase in current associated temperature rise) and a shearing of the predetermined breaking points takes place. Since thus in the known arrangement of the interruption current conductor and its predetermined breaking points permanently below the force of interaction between the main current and that generated by it in the magnet winding Magnetic field, the interrupting conductor must be equipped with a for this continuous load (under

609 537/288

allowance for permissible overcurrents) must have sufficient strength. Accordingly, the Interrupting current conductor in the known arrangement has the shape of a substantially cylindrical Head.

The invention thus also relates to an electrodynamic high-performance high-speed switch a current conductor located in the high-power circuit to be switched as a target interruption point, which is under the influence of a magnetic winding and for arbitrary circuit interruption regardless of the current strength based on the interaction with the magnetic field of the winding Forces is mechanically destroyed. The invention is intended to be a on the mentioned, in a Over-current switch, fast-acting switches based on the well-known principle for arbitrary circuit interruption of high currents are created, which meets the requirements mentioned at the beginning for the switching of such high-current systems enough.

For this purpose, a high-performance electrodynamic high-speed switch of the type mentioned is in accordance with of the invention designed so that a thin metal foil is provided as the interrupter current conductor is and that a separate excitation circuit from the main circuit for the Main circuit electrically separated magnet winding is provided, which has its own voltage source and a switching device for the optional, instantaneous excitation of the magnet winding has such that when the magnet winding is energized by actuating the switching device in the metal foil by the magnetic field of the magnet winding strong eddy currents are induced whose magnetic fields in turn interact with the Magnetic field of the magnetic winding occur, whereby the film is instantly torn.

In the switch according to the invention, the magnet winding is thus electrical from the main circuit completely separated and becomes from a separate circuit of excitation in an arbitrary one selectable switching time excited. The conductor serving as an interruption point is thin Foil formed; this training is of particular importance in two respects: On the one hand, it ensures the formation of intense eddy currents as a result of the short-term excitation the magnet winding. The secondary magnetic fields associated with these eddy currents occur with the Primary field of the magnetic winding in interaction, causing the destruction of the conductor Force is therefore primarily an interaction between magnetic fields, which caused by the flow of current in the separate excitation circuit and by the main current are essentially independent in the circuit to be switched. On the other hand, the Formation of the interruption current conductor as a thin film, the immediate complete tearing and interruption of the film, d. H. that the interruption current conductor with sufficient conductivity for the main current (and good conductivity for the formation of eddy currents) with a relatively low mechanical strength can be formed at the predetermined breaking points to do this more so than the film only at the switching point of the mechanical stress due to interaction forces is exposed, i.e. at a point in time when it is intended to tear, and not as in the case of the known arrangement, also in the steady state in the range of the permissible current strengths.

In the switch according to the invention, in contrast to the known overcurrent protection switch, the switching process and the interaction required for the interruption thus of the state in the main circuit to be switched is basically completely independent, since the interaction is based solely on effects caused by the secondary circuit, namely on the primary field of the magnetic winding and on the secondary fields, which are connected to the Primary field in the foil induced eddy currents are linked. The switching action is therefore independent whether in the main circuit a medium, a particularly high or a weak one Electricity flows.

The combination according to the invention of a foil-shaped interrupting current conductor with an independent one Excitation circuit for the magnet winding ensures that the interruption is also higher Currents with a short switching duration that cannot be achieved with the known arbitrary high-speed switch he follows; further is achieved in that the interruption up to significantly higher currents, than was previously possible, takes place practically arc-free, so that devices for arc extinguishing are not required in the quick switch according to the invention.

According to an advantageous embodiment of the invention it is provided that the film with uniform Thickness is formed and consists of a refractory metal, which has good conductivity for the eddy currents induced by the magnetic field of the winding; for example can the foil consist of a metal from the group aluminum, copper and silver.

According to an advantageous embodiment of the invention it is provided that the switching device for the excitation circuit of the magnet winding has a thyratron.

According to a preferred embodiment it is provided that the film has a central opening in such a way that between the opening and the edge of the foil narrow foil parts remain as predetermined tear points, and that the magnetic winding is arranged with its core coaxially to the central opening of the film is such that one end face of the magnet winding is in close proximity to the one mentioned Foil narrow parts and lies parallel to them.

Further advantages and details of the invention emerge from the following description of a Embodiment based on the drawings; in these shows

Fig. 1 is a partial representation of an embodiment of the invention in plan view,

Fig. 2 is a partial sectional view along the line H-II in Fig. 1,

3 shows a partial representation of the arrangement in plan view from Fig. 1 after tearing the foil,

4 shows a circuit diagram of a test circuit with the switch according to the invention,

5 shows a schematic representation of an oscilloscope which is used to display the for the opening process the device according to the invention is calibrated in the circuit in FIG. 4 required time period.

F i g. 1 shows a switch 11 according to the invention as an advantageous embodiment which is particularly suitable for interrupting a high-power circuit for the ohmic heating of plasma in plasma research reactors or stellarators. Such reactors are described in U.S. Patents 2,910,414 and 3,002,912 and in U.S. Pat. 3 016 341 (corresponding to German Patent 1 109 277), which relate in particular to ohmic heating coils for heating a plasma to high temperatures . Of course, the switch according to the invention can also be used for any other application which requires a fast-acting switch, especially in those cases where the sudden disconnection of high voltages is necessary without arcing and without melting or burning the contacts; With the switch according to the invention this can be achieved in a simple, cost-saving, safe and trouble-free manner 2.0 .

In Fig. 1, lines 13 and 15 connect the input and output terminals (not shown) a conventional energy source 17, for example a high voltage source for (not shown) Ohmic heating coils in a stellarator, which requires up to 1000 amps or more. the Conductors 13 and 15 are in a suitable manner, for example by means of soldered connections, each with the one End of terminals 23 and 25 connected. The connecting terminals protrude at their other ends through openings 26 and 27 at the ends of a metal foil 31, which in the friction fit against the terminals 23 and 25 and against an insulator block 33 through which the terminals Guide 23 and 25 through. By this friction fit with the terminals 23 and 25 is a circuit from the source 17 via the line 13, the film 31, the line 15 back to the source 17 is closed, through which a current of high energy from the source 17 is conducted.

The film 31 is preferably held flat against a winding 34; to this end the film 31 is formed with a uniform thickness and width and between the clamps 23 and 25 kept at least uniformly under tension so that they on one side of the winding 34 fits tightly. The film 31 is pressed against the terminals 23 and 25, which is a short Piece protruding above the surface 35 of the block 33 in order to obtain the required tension. For this purpose, the clamps are slightly opposite the openings 26 and 27 in the film offset. As a result, the narrow points 43 and 45 of the film 31 are also on the end-face turn of the spool 34 by centering the opening 47 of the foil on the core 50 of the spool 34. A foil 31 designed for a current line of 1000 amperes can have the following dimensions: Thickness 0.1 cm, width 2.54 cm, length 3.2 cm, diameter of opening 47 1.27 cm. Commercially available Sheet aluminum, which is easy to process and inexpensive, has proven suitable for the foil 31. It however, other refractory materials such as silver, copper and others also come Metals in question, which have sufficient electrical conductivity, as described above, as well a good ability for magnetically induced eddy currents and associated magnetic fields as will be described in detail below.

Commercially available coils with designed for high voltages are preferably used for the coil 34 Turns used. For example, a single layer coil with 10 to 30 turns and 3.2 cm outside diameter, which can withstand up to about 10,000 volts. the Coil 34 is preferably in a regular plastic molding block 33 of insulating material included with the spool core 50 coaxially aligned with the opening 47 of the film. The block 33 thus isolates the film 31 from the coil and keeps the coil 34 at a predetermined small distance of the narrow points 43 and 45 of the film 31. The insulator block 33 preferably consists of one castable plexiglass-acrylic thermoplastics; it can however, other dielectrics can also be used, provided they have sufficient dimensional stability and have high magnetic flux permeability. In this regard, insulator materials come for lower temperatures, such as wax, conventional plastic materials such as Polytetrafluoroethylene, polyester resin, phenol resinoid, phenol formaldehyde, cast synthetic resins, polyvinyl chloride, Epoxy resins as well as ceramic insulator materials and the like in question, in which the coil 34 can be used.

The energy source 61 comprises a suitable high power multiple capacitor on, which energizes the coil 34 at predetermined intervals via a suitable low-voltage switch 63, whereby the voltage on the coil 34 increases by leaps and bounds. A gas-filled thyratron tube serves as the switch 63. A line 65 connects the power source 61 to the coil 34 via the thyratron 63; one with one Mechanical switch 65 connected to low voltage source 67 blocks the thyratron until one Excitation of the coil 34 is desired. At this point, the contacts of the switch 65, the The blocking of the thyratron is canceled, the thyratron 63 becomes conductive and the capacitor 61 is energized the winding 34 by leaps and bounds. This creates a strong, rapidly increasing first magnetic field the winding 34 is generated, in which the film 31 is arranged. As a result, they will be strong, increasing Eddy currents with second magnetic fields in the narrow parts 43 and 45 of the film 31 below at an angle to the first magnetic field. The mentioned first magnetic field and these second magnetic fields enter with each other with great violence, but at relatively low temperatures Interaction and break the film at the narrow points 43 and 45, as in F i g. 3 shown.

The operation of the device according to the invention will now be described. Operational initially high currents flow through the film 31 from the source 17 until the circuit, in which the film 31 is to be interrupted quickly and instantly. At this point in time the pressure switch 65 is actuated, whereby its contacts open and the switch 63 ignited will. This causes the multiple capacitor 61 to jump through the winding 34 discharges, as a result of which the film 31 is penetrated by a strong, increasing magnetic field, which through the coil 34 is generated. This first magnetic field

causes strong, increasing eddy currents in the narrow areas 43 and 45 of the film 34, the corresponding magnetic fields around the eddy currents at an angle to the first, cause the winding 34 generated magnetic field. The first magnetic field and those mentioned Second magnetic fields interact vigorously and act on the assigned one Foil 31, which you can quickly and safely at the narrow points 43 and 45 at relatively tear at low temperatures. For example, tests have shown that the temperature of the film increases from room temperature to around 85 ° C when a voltage of 10,000 volts is applied the coil 34 was discharged and the foil 31 conducted a current of 1000 amperes. Test attempts with Ohmic heating coils for stellarator systems have also shown that the switch according to the Invention with high melting point films is fast acting; the foil 31 is in the arrangement instantly interrupted according to the invention by a physical breaking process without that under the given conditions a noticeable arcing or stewing effects occurred. Practical test measurements have also shown that the film 31 tears in 100 ± 12 microseconds is interrupted, as in Fig. 5 with reference to the schematic representation using an oscilloscope tracer is indicated. To record this oscilloscope image, a direct current level was used as shown in FIG set by a battery 71 which generated a current flow through the foil 31; the The oscilloscope trace was calibrated in microseconds to determine the time / voltage characteristics of the battery current flowing through the foil when the foil is interrupted by the excitation of the winding 34 to get. After the foil is torn, a new foil is placed between the terminals 23 and 25 placed and the actuation process repeated as described above.

With the help of the fast-acting switch according to the invention described above, a The circuit can be interrupted instantly with a sharp shutdown. The switch according to the invention ensures safe, reliable, cheap with conventional, commercially available components and trouble-free operation without any detectable arcing or scorching phenomena on the switch components.

Claims (7)

Patent claims: 1. Electrodynamic high-performance high-speed switch with a high-performance circuit to be switched lying current conductor as a target interruption point, which is under the influence of a magnetic winding and to the arbitrary Switching interruption regardless of the current strength due to the interaction with the The forces based on the magnetic field of the winding are mechanically destroyed, characterized in that that a thin metal foil (31) is provided as an interrupter current conductor and that a separate one from the main circuit (11) special excitation circuit for the magnet winding, which is electrically separated from the main circuit (34) is provided, which has its own voltage source (61) and a switching device (63, 65, 67) for the optional, instantaneous excitation of the magnet winding in such a way that that when the magnet winding (34) is excited by actuating the switching device (63, 65) in the Metal foil strong eddy currents are induced by the magnetic field of the magnet winding, their magnetic fields in turn interact with the magnetic field of the magnetic winding (34) occur, whereby the film (31) is instantly torn. 2. Switch according to claim 1, characterized in that the film (31) with uniform Thickness is formed and consists of a refractory metal, which has good conductivity for the eddy currents induced by the magnetic field of the winding (34). 3. Switch according to claim 2, characterized in that the foil is made of a metal Group consists of aluminum, copper and silver. 4. Switch according to one or more of the preceding claims, characterized in that that the switching device (63, 65, 67) for the excitation circuit (61, 65, 34) of the magnet winding (34) has a thyratron (63). 5. Switch according to one or more of the preceding claims, characterized by at the same time acting as connecting terminals pins (23, 25) which at the ends of the film (31) protrude through these and keep them under a uniform mechanical tension. 6. Switch according to one or more of the preceding claims, characterized in that that the film (31) has a central opening (47) such that between the opening and the edge of the film narrow film parts (45, 43) remain as predetermined tear points, and that the magnet winding (34) with its core (50) arranged coaxially to the central opening (47) of the film (31) is such that one end face of the magnet winding is in close proximity to the one mentioned Narrow film parts (43, 45) and lies parallel to them. 7. Switch according to one or more of the preceding claims, characterized by a block-shaped body (33, 35) made of insulating material in which the magnet winding (34) and serving as connecting terminals and mechanical holder for the film (31) Pins (23, 25) are arranged at intervals. Considered publications:
German interpretative document No. 1 071 208. 1 sheet of drawings 609 537/288 3.66 © Bundesdruckerei Berlin