Current limiting device

[Detailed Description of the Invention]

To do J and l target [Industrial Application] The present invention relates to the current limiter using what is called a quench phenomenon of the superconductivity object.

[Description of the Prior Art] In recent years, the proposal of Okuma and others which the trial which applies a superconductivity object to a current limiter is conducted, for example, was published at the 169th page of the 1st international superconductivity symposium proceedings is known. The current limiter proposed here (the superconductivity ceramics (Y B a 2 Cu a 07-!) of Granting yttrium barium, copper, and an oxygen system are processed 30 cm in length in the shape of a grid, and this is connected between current terminals, and it is allocated all over a circuit, and cooled and used by liquid nitrogen.) If the current beyond critical current is sent by this current limiter, superconductivity ceramics will transfer to a usual state conduction state from a superconductive state, and will play the Limit style operation by usual state conduction resistance. This current limiter (since transition to the usual state conductor by quench phenomenon is used, it excels in a response.)

[Problem(s) to be Solved by the Invention] However, the current limiter using such a superconductivity object (when momentarily excessive current flows according to power turn-on Iri [ Tokiji ] incoming current like for example, a lamp motor in front load) In spite of constituting so that a Limit style operation may be played for the first time when the current which the problem that it cannot be used does not work by Shoulder strap, i.e., the normal incoming current expected that there is nothing, but exceeds amperage rating [ predetermined time ] flows, Shortly after reaching [ the above-mentioned conventional current limiter ] amperage rating (critical current), in order to play a Limit style operation, * problem of carrying out a Limit style in incoming current if it uses for a lamp etc. is Asahi. The problem that these apparatus cannot fully be protected from an over-current if moment permissible current, such as a Up L lamp, was constituted as critical current is Asahi. The current limiter of the present invention has a high-speed response, and it solves this problem, In incoming current, it operates, when the current exceeding amperage rating energizes [ predetermined time ], although not operated, and it aims at protecting apparatus exactly against an over-current according to the operation conditions of apparatus that this current limiter was attached. 1 Ablation [Means for solving problem] Current limiter 1 Gourd of - present invention It is a current limiter which regulates the current which will use the quench phenomenon of the superconductivity object transferred to a usual state conduction state from a superconductive state if the current exceeding critical current is sent, or if it becomes the temperature exceeding critical temperature, and flows between current terminals, The 1st superconducting member that causes a quench phenomenon in the 1st predetermined critical current, and it transfers to the resistance object of usual state conduction is connected between the above-mentioned current terminals, The 2nd superconducting member that causes a quench phenomenon in the 2nd bigger critical current than the 1st above-mentioned critical current, and it transfers to the resistance object of usual state conduction, It connects with the resistance heating element and series which were allocated in the position which heats the 2nd superconducting member, and the 2nd superconducting member and the resistance heating element are connected with the 1st above-mentioned superconducting member between the above-mentioned current terminals at parallel, and let things be gists.

[Function] On current limiter C which consists of the above-mentioned composition Between current terminals, it has two energization courses, a 1st superconducting member side and the 2nd superconducting member side. Since the resistance heating element is connected in series, this 2nd superconducting member side will always have the resistance more than fixed. Therefore, when both members of both are in a superconductive state (current is sent for resistance via the course by the side of the 1st [ of zero ] superconducting member when the current below the 1st critical current (I cl) is sent between , i.e., a current terminal.) When the current below the 2nd critical current (I c2) is sent between current terminals on the other hand more greatly than the 1st critical current (lcl) (current is sent via the course by the side of the 2nd superconducting member to which resistance became small relatively since only the 1st superconducting member of a table causes a quench phenomenon.) Then, a resistance heating element generates heat by this current, and it is begun to heat the 2nd superconducting member. If current continues flowing into this resistance heating element beyond predetermined time and the temperature of the 2nd superconducting member rises to critical temperature, the 2nd superconducting member will also cause a quench phenomenon shortly. To this appearance To the current of this range, a Limit style operation is played after progress of predetermined time. furthermore -- the case where the current which exceeds the 2nd critical current (I c2) between current terminals is sent -- the -- when the 1. 2nd superconducting member both causes a quench phenomenon and transfers to a usual state conduction resistance object, a Limit style operation is played immediately. When current falls and below each critical current (cl, Ic2) becomes after a Limit style operation, a superconducting member returns to a superconductive state automatically, respectively, and a Limit style operation stops working. the above result -- the current limiter of the present invention -- after all -- When current is l > l c2, a Limit style operation is played immediately, and when one or more-Ic current continues flowing [ predetermined time ] in the case of l cl< I<=lc2, a Limit style operation is played.

[Example] Next, one example of the current limiter of the present invention is described. Drawing 1 is a lineblock diagram of an example. It is li to the current limiter of an example. The 1st superconducting member 1 designed so that a quench phenomenon might be caused by 1 cl of the 1st critical current corresponding to the amperage rating of a motor (illustration abbreviation) and the big resistance of usual state conduction might be shown, The 2nd superconducting member 2 designed so that a quench phenomenon might be caused by the 2nd critical current 1c2 corresponding to the moment permissible current of this motor and the big resistance of usual state conduction might be shown is used. Here, as these superconducting members 1 and 2, ceramic system high-temperature superconducting bodies, for example, the thing which formed B a 2 Y Cu 30 ?-11 in the shape of a grid, such as TIB a -Ca -Cu-0 system, a Ba-Y-Cu-O system, and B i-8 r-Ca -Cu-0 system, are used. Critical current of the superconducting member formed from such materials (mind [ Becoming settled with critical current density Jc which becomes settled from the material physical properties of this high-temperature superconducting body, and the cross-sectional area of a grid, the resistance after transferring to a usual state conduction state becomes settled by the cross-sectional area length and material physical properties of a grid. ]) taking these into consideration and determining the cross-sectional area of a grid based on permissible current at the amperage rating of a motor, and the moment -- Further hide determining the length of a grid, as big resistance is shown in the state of usual state conduction -- the -- the 1. 2nd superconducting member 1.2 is designed. The 1st superconducting member 1 obtained in this way is connected between 3 or 3 degrees of current terminals, electrically connecting to the 2nd superconducting member 2 in series resistance heating element 4 stood in a line and arranged so that this 2nd superconducting member may be heated -- To et al. [ 2 ] -- a current limiter is constituted by connecting these 2nd superconducting members 2 and resistance heating element 4 between current terminal 3 and 3' in parallel with the 1st superconducting member 1. This current limiter (maintained below at the critical temperature of the high-temperature superconducting body which was put in in friend cooling container 5, and was used as a cooling A bill superconducting member in liquid nitrogen.) And 6 or 6 degrees of current supply lines of a motor (illustration abbreviation) are connected to 3 or 3 degrees of current terminals. Current supply line 6.6 Seal fixation is carried out in epoxy resin 7 and 7 * at cooling container 5. Next, the operation of the current limiter of this example is explained based on the timing chart of Drawing 2. the case (the [ friend ] -- the 1. 2nd superconducting member 1.2 has each in a superconductive state.) where current 1 is below the 1st critical current (I<=IC1) Since resistance heating element 4 is connected to the 2nd superconducting member 2 side in series, the circuit by the side of this 2nd superconducting member 2 shows predetermined resistance. Therefore, current flows through the circuit by the side of the 1st superconducting member 1 whose resistance is zero. Since resistance is zero, a Limit style operation does not work at all in this case (time TO~TI). In a direction, in order that the 1st superconducting member 1 of 1 A may cause a quench phenomenon in below the 2nd critical current (l cl< I<=IC2) and current 1 may show big resistance to it more greatly than the 1st critical current, current flows through the 2nd superconducting member 2 side with small resistance relatively. Therefore, resistance heating element 4 begins (time TI) to generate heat. The calorific value per unit time of resistance heating element 4 is decided by 2(current)x (resistance), and the temperature of the 2nd superconducting member 2 rises according to x (/(the amount of heat dissipation of calorific value-superconducting member 2 of a resistance object) (specific heat of superconducting member 2)) (time). However, current 1 is practice 11 to the inside of a short time like the incoming current which can be set motor load 2 smaller than the 1st critical current lcl. Accumulation of the quantity of heat given to the 2nd superconducting member 2 is small, and the 2nd superconducting member 2 does not reach critical temperature (time T2). Therefore, in such a case, a Limit style operation does not work but stops only at the voltage drop of the part which is slightly equivalent to the resistance of resistance heating element 4 occurring (time T1~T2). Since the 1st superconducting member 1 will return to a superconductive state immediately and will serve as resistance zero if current 1 turns into 1 cl or less of the 1st critical current again (1<=IC1) (time T2), a Limit style operation does not work at all (time T2~T3). the case where the excessive current which exceeds permissible current on the other hand in the 2nd bigger current, i.e., a moment, than critical current lc2 flows -- the [ (+> l c2) and ] -- the 1. 2nd superconducting member 1*2 both causes a quench phenomenon, big resistance is shown, and a Limit style operation works immediately (time T4). On the other hand, it is even if it is 1c2 or less (l cl< l<=IC2) critical current [ 2nd ] current more greatly than 1 cl of the 1st critical current, If this current continues flowing beyond predetermined time and generation of heat of resistance heating element 4 continues (time T5~T6), the temperature of the 2nd superconducting member 2 will rise gradually, and will result in critical temperature (time T6). since [ then, ] superconducting member 2 of shoulder 2 causes the quench phenomenon by critical temperature and transfers to strong resistance -- a big voltage drop -- a Arching elasticity Indeed style operation - it works. On time 1 until this Limit style operation works It can set to various conditions by adjusting the arrangement interval of resistance heating element 4 and the 2nd superconducting member, or adjusting resistance by the length and material selection of a resistance heating element. When exceeding amperage rating according to the current limiter of this example as explained above, but flowing momentarily to the current below permissible current at the moment, a Limit style operation does not work, but only when the current of this range continues beyond predetermined time and flows, a Limit style operation can work. As a result, although it does not react to incoming current to the apparatus which must permit the incoming current which exceeds amperage rating like a motor, when the lock current which exceeds amperage rating [ predetermined time ] like [ when a motor locks ] flows, a Limit style operation can work. When the excessive current which exceeds permissible current at the moment flows, a Limit style operation works immediately. and a Limit style operation on the excessive current which exceeds permissible current at the moment --] -- Since the phenomenon of the quench phenomenon of a superconducting member in which resistance changes extremely at high speed is used, a response is very good. The ground Since a Limit style operation works using the quench phenomenon of a superconducting member, if over-current conditions are lost, it can return automatically. Thus, since the Limit style operation corresponding to the operating condition of a motor etc. is played, these apparatus can be exactly protected from an over-current, without barring that operation. What the resistance of this resistance heating element 4 is adjusted, or the interval of resistance heating element 4 and the 2nd superconducting member 2 is adjusted for since it had composition which heats the 2nd superconducting member 2 by accumulation of the calorific value of resistance heating element 4 more than critical temperature, since the current exceeding amperage rating begins to flow, various time until the 2nd superconducting member 2 causes a quench phenomenon by critical temperature can be boiled and set up. therefore, it is possible to design to versatility according to the lock time which can permit a motor, and it can also form a lock timer. Having-composition which heats 2nd superconducting member 2 to critical temperature by accumulation of calorific value of resistance heating element 4 1 mountain When this over-current exceeds amperage rating greatly, the effect that a Limit style operation will work early is produced (2nd [ The ] figure dotted line). Therefore, according to the grade of an over-current, these apparatus can be protected exactly. This current limiter of the ability to use as a current limiter for over-current prevention to not only a motor etc. but all kinds of apparatus is natural, and its scales are natural, using all kinds of superconductivity object as a superconducting member. Although one example of the present invention was described above, The present invention is not limited to such an example at all, For example, insulating coats, such as a fluoro-resin, are formed in the surface of the 2nd superconducting member 2, and, of course, it can carry out in the mode which becomes various within limits which do not deviate from the gist of the present invention, such as constituting it from on this as the resistance heating element of a ribbon base is twisted. ■ Cliff punishment 1 Result getting twisted in the current limiter of the present invention, as explained above (a melon -- to the 2nd critical current, a Limit style operation works immediately to two current conditions of the 1st critical current, and the 2nd critical current, and a Limit style operation can work according to energization continuation time to the 1st critical current.) On time of onset 1 of a Limit style operation on this 1st critical current It connects with the 2nd superconducting member in series, and since it is decided from the cumulative calorific value of a resistance heating element which heats this, the Limit style operation according to the grade of the over-current can be played. This result These apparatus can be exactly protected against the apparatus which must permit the incoming current exceeding amperage rating according to the grade of an over-current, without barring that operation. The ground Since the phenomenon of the quench phenomenon of a superconducting member which occurs extremely at high speed is used, when exceeding the 2nd critical current, it is on one. It is effective in answering at high speed. Therefore, apparatus can be protected quickly. Since it has composition which a Limit style operation commits using To 1: and the quench phenomenon of a superconducting member, if over-current conditions are lost, it can return automatically.

[Brief Description of the Drawings]

Drawing 1 is a schematic structure of present invention 1 example. Drawing 2 is a timing chart explaining the operation of the current limiter of an example.