Superconducting coil

As well known the transition of the superconducting to the normalleading condition of a superconducting coil depends not only on the temperature, but also on the current density in the superconductor and the magnetic field, it is exposed to which. During the calculation of a solenoid coil the limit value of the load is theoretically not accurately certain. One is therefore dependent for the determination of this limit value, whose knowledge is fiir an economic utilization of the coil of interest, on an attempt. For this purpose the current load der8pule is so far increased, until Transkion, which is the transition of the superconducting to the normalleading condition, enters. The Transition begins to steep ones and spreads over the entire coil. So that the local heating becomes not too large, one, as was already suggested, can plan means, which accelerate the propagation of the Transiüon over the entire coil. Such means consist either of creating a good heat transition between the individual turns nnd windings or not pushing away by bypass of coil parts by means of resistances the magnetic through flow on yet the coil parts gone into Transition. Despite these measures it can occur and it with practical attempts already showed up that one can be only loaded once in Transition coil gone with for example 80% the previous Grenzteistung that thus with the first Transition rougher damage arises. A superconducting coil is created by the invention, with which the limit value of the permissible load lets itself in such a way ermitteha that thereafter an enterprise without gröflere Einbufle at maximum stress is possible. With a superconducting coil, whose coil is divided into several Teilwlcklungen from each other separated by thermal insulation, this is reached according to invention by it, dal3 at the electrical junction points of the TeilwieklungenWiderstände for the Weimrleitung of the warmth and after zeroes gefilhrte electrical pick-ups is intended. The invention is the basis the thought not to weaken those with the practical determination of the Grenz'wertes of the excitation arising Transidon in their effect to locate but. Thus consciously a damage is taken in purchase. Damages part can however by bridging at the coil already intended pick-ups, without mechanical interference into the coil be made easily unsekundlich. DasLokalisieten of the damage is reached by that the entire coil of the coil into many partial coils, which are warm-moderately from each other separate, are divided and that the electrical junction points of the Teilwickluagen are decoupled through resistances for the forwarding of the warmth. The damage of the partial coils which can be sacrificed may accept however none such extent that it, for example by sparking, pulls also the neighbouring Teihvicklungen in. Gemäßeiner further training of the invention are planned therefore still means, in order to spread the Transition arising in a partial coil as fast as possible over the partial coil concerned. Hiebei is to be noted that when using Mkteln, which limit-remains by a shifting of the magnetic through flow of turns gone into Transition on neighbouring turns an acceleration of the spreading of the Transit/on to cause, this effect on the coil part which can be sacrificed. Therefore a shorted turn must be planned in this Pa11, which takes over the magnetic Durchflutung in place of the remaining partial coils. The invention is described by a remark example on the basis a figure. In the figure a superconducting coil is represented, whose coil 1 in Teih “icklungen 2, 8, 4 and h is subdivided, the through thermal insulations 6, 7 and 8 from each other separate is. At the electrical junction points of the partial coils thermal resistances are 9! 0 and 11 intended. These consist of a Metallmantcl of large thermal capacity with good heat transition to the '3upraleiter, in addition the VerbindungssteUen is provided with pick-ups 12, 18 and 14 led outward. The Konmktstellen between the pick-ups and the magnet wire is put zweclu näßig into an area with smaller magnetic field, since by contacting the superconducting characteristics of the magnet wire are generally somewhat worsened and it are better if they are exposed to a smaller magnetic field. One arranges the contact points for example at the outer casing that-reels within the Wärmeisolafion on. The coil beginning of 15 and the end of reel 16. are outward led just like the pick-ups by the Wärmeisoladon 1 ' 7. With the symbols 18 and t9 are suggested the Zuund derivative of the Kühlfiüssigkeit. If the superconducting coil is taken inEetrieb and if the current supply over the ends of reel is slowly increased, then in any place with the exceeding of the critical current density and the kriüschen field strength the coil will change from the superconducting into normalleitendcn the condition. It is angenormen that this Transifion in the partial coil 5 arises. It spreads from the developing place partial coil up to the thermal resistance 11 to within that. The way to the neighbouring partial coil 4 is closed directly by the Wärmeisoläfion 8, the way over the galvanic connection between the Teilwieklungen 4 and fi by the thermal resistance 11. Consequently the effect of the Transition is limited to the range of the partial coil 5. By the pick-ups 12 - 14 28 one has the possibility already during first switching on on of recognizing the partial coil which the Transidon enters. One needs to seize for this purpose only the tensions between the pick-ups oszillographisch. The possibility also later exists of determining on the basis a resistance test become bad the TeilwickIung without _Eingriff into the coil. One can determine the limit value of the load and the place of the damage with such a coil thus simply. For the further enterprise one needs to only ensure that the limit value any longer not reached and the damaged SpulenteiI is bridged over the led out pick-ups. This can likewise happen without mechanical interference into the coil. With solenoid coils with very much large energy content, as previously mentioned, the danger exists that with the Transition örtlic the ne heating becomes so strong that the isolation is damaged for neighbouring partial coil and thus a larger part, perhaps even the entire coil is drawn in. Therefore favourable-prove still further measures are intended, the propagation of the Transition over the partial coil concerned beschleunigun. The pieces of metal 20 with the Ausfü'hrungsbeispiel, which are folienFörmig trained, serve this purpose and which surround partial coils. They-leads the local heating due to its small thermal resistance fast on neighbouring turns of the same partial coils off and causes on the one hand a cooling at the place of the Transirion and on the other hand a heating up of the neighbouring turns i.e. a faster propagation of the Transition. Which effect outweighs hiebei, lstücke depends on the calculation of the Meta]. If they are equipped with very large Wärmekapav.ität for example thereby that they are provided with cavities, through dic Kühlflüssigkcit is led, then they will only slightly warm up it outweigh themselves thus de: first effect. If they possess a smaller Wärmekapazitä.t and a very large heat conductivity, then the warmth of the Enstshungsort spreads fast over the entire partial coil. It outweighs thus the second effect. Also the attachment of Widerstandsbrücken serves an acceleration of the propagation of the Transition between denWindungen or embedding the magnet wire into a conductive paint. 21. As material lüefür, that must be once-off-selected effectuation that in the superconducting condition the river essentially flows by the magnet wire and in the normalleading condition the river over the conductive paint. During this condition in case of the Transition of a turn the magnetic Durchflutung is pushed away on the other turns. So that this Durchflutung is not taken up by the remaining Teilwieklungen - these are not to remain if possible langim for superconducting condition their amperage to increase - but remains practical in the partial coil which can be sacrificed, it is necessary when using Widerstandsbrücken or LeitIack to design the pieces of metal 20 as Kurzsehlußringe. These take over then due to the substantially longer time constant practically the entire energy content.