JPS5941258B2 - Short circuit current detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION As shown in FIG. 1, the conventional short-circuit current detection device has a salient magnetic pole b protruding from the inner surface of one end wall a of the yoke a, and a tip portion protruding from the other end wall a of the yoke a. A spring d that faces the proximal end surface of the movable iron core c that can be slid through the salient magnetic pole b with a gap therebetween, and that acts in a direction to separate the movable iron core c from the salient magnetic pole b. The salient magnetic pole b and the movable iron core c
The coil f is wound around the outer circumferential side of a cylindrical coil frame e, which is mounted so that the inner circumferential body faces the outer circumferential side of the coil frame e. When a short-circuit current flows, the magnetic flux created by the short-circuit current flowing through the coil f attracts and moves the movable iron core c to the salient magnetic pole b against the force of the spring d, and the short-circuit current can be detected by the movement of the movable iron core c. I can buy things.

However, when the movable iron core c is attracted to the salient magnetic pole b due to a large current flowing through the coil f, which is necessary for the movable iron core c to start being attracted to the salient magnetic pole b, the attractive force F3 is
The relationship between the gap G4 between the tip end surface of the salient magnetic pole b and the base end surface of the movable iron core c is as shown by the curve Al in FIG. 2, and the relationship between the spring force F' of the spring d and the gap G. becomes the straight line B in Figure 2, and when the movable iron core c is attracted to the salient magnetic pole b due to the large current flowing through the coil f, which is necessary for the movable iron core c to start being attracted and moved to the salient magnetic pole b. The energy is equal to the area 51 of the hatched area surrounded by the vertical axis, the curve Al, and the straight line B3 in FIG. 2, and since the area 51 is small, the movable iron core c starts to be attracted to the salient pole b When a short-circuit current approximately equal to the large current required for the above-mentioned short-circuit current flows through the coil f, the movable iron core c is not quickly attracted and moved, resulting in the drawback that the short-circuit current cannot be detected quickly. The present invention is intended to eliminate the above-mentioned drawbacks of the conventional art.Examples of the present invention will be described below with reference to the drawings.Denoted at 1 is a yoke having an opening-shaped cross section, and 2 is an inner surface of one end wall 1a of the yoke 1. The protruding salient magnetic pole 3 is a movable iron core whose tip portion can be slid through the other end wall Ib of the yoke 1;
Its base end face is opposed to the tip end face of the salient magnetic pole 2 with a gap therebetween.

4 is a spring that acts in a direction to separate the movable iron core 3 from the salient magnetic pole 2; 5 is a cylindrical coil frame 6 to which the inner circumferential body is mounted facing each other on the outer periphery of the salient magnetic pole 2 and the movable iron core 3; Coils to be wound on the outer circumferential side, T and T' are V-shaped or arc-shaped engagement grooves formed on both sides of the tip of the movable iron core 3, 8, 8'&: the outer surface of one end wall 1b of the yoke 1 The engagement groove 7 of the movable iron core 3 is slidably inserted into the cylindrical body 9, 9'' to be fixed to the movable iron core 3.
, r, and a rod-shaped engagement groove 7 attached to the outer surface of the one end wall 1b so as to slide in a direction perpendicular to both side surfaces having a diameter of 1.
7'', one end of which is a locking piece having a semispherical curved surface, and an adjustment screw 1 that is screwed onto the inner peripheral body at the proximal end of the cylindrical body 9, 91.
Spring 11 that can press the other end on each tip of 0,105
, 1V, the locking pieces 8, 8'' are fitted and pressed into the engagement grooves 7, 7''.

According to the present invention, the salient magnetic pole 2 may be removed and the base end surface of the movable iron piece 3 may be opposed to the inner surface of one end wall 1a of the yoke 1 with a gap placed therebetween. The present invention has the above configuration, and the third
In the state shown in the figure, when the coil 5 is inserted and connected in series to the distribution line and an overcurrent of more than a predetermined value flows through the distribution line, the movable iron core 3 is attracted to the salient magnetic pole 2 side by the magnetic flux created by the short-circuit current flowing through the coil 5. Therefore, the locking pieces 8, 8'' are connected to the locking groove 7.
, 7I-shaped or arc-shaped slopes is pushed up against the pressing force of the springs 11 and 1V, and the movable iron core 3 comes out of the locking grooves 7 and r, and the movable iron core 3 becomes the salient magnetic pole 2.
The short circuit current can be detected by moving the movable iron core 3 to the side.

Then, the attractive force F when the movable iron core 3 is attracted to the salient magnetic pole 2 by flowing through the coil 5 a large current necessary for the movable iron core 3 to be attracted and moved by the salient magnetic pole 2, and the salient magnetic pole 2
The relationship between the gap G between the movable iron core 3 and the movable iron core 3 is as shown by the curve A in FIG. piece 8,8
The relationship between the resultant force r with the resistance force of ″ and the gap G is as follows:
As shown by curve B in FIG. 4, the resultant force r suddenly increases only when the gap G is near the maximum gap G. because. Only when the gear G is near the maximum gear σ,
The locking pieces 8, 8' are fitted and pressed into the locking grooves 7, 7'' of the movable core 3, and the locking grooves 7, r of the movable core 3 are pressed against the movement of the movable core 3 toward the salient magnetic pole 2 side. This is because a resistance force is generated due to the slope of the locking pieces 8, 8'' being pushed up against the pressing force of the springs 11, 1V. Note that the locking pieces 8, 8' are in the locking groove 7.
, r, the locking pieces 8, 81 press the movable iron core 3 with the pressing force of the springs 11, 1V, but the sliding contact surface between the locking pieces 8, 8' and the movable iron core 3 Since both are smooth curved surfaces and sliding surfaces, the resistance force against movement of the movable iron core 3 toward the salient magnetic pole 2 side is negligible.
In other words, when curve A in FIG. 4 and curve A1 in FIG. 2 are similar, the curve in FIG. Therefore, when a short-circuit current approximately equal to the large current required to attract and move the movable iron core 3 toward the salient pole magnetic pole 2 side flows, the movable iron core 3 becomes the salient pole. The energy attracted and transferred to the magnetic pole 2 (as shown in Figure 4,
Area S of the shaded area surrounded by the vertical axis and curves A and B
be equivalent to. ) becomes extremely large as the resultant force r suddenly increases only when it approaches the maximum gap G, and when a short-circuit current flows through the coil, the movable iron core can be quickly attracted and moved to the salient magnetic pole side, and the short-circuit current can be detected quickly. When a conventional short-circuit current detection device and a short-circuit current detection device of the present invention were compared with each other with a maximum gap G of 2.5 ml, the following results were obtained.

In other words, the gap of the conventional spring d is 2.5 m7.
7! 300g when the gap is 0mm, 500g when the gap is 0mm
r and the spring force of spring 4 of the present invention with gap 2.
．． 100 gr for 5 dragons, 0 gap! 20 when Nm
0g, the slopes of the locking grooves 7, r of the movable core 3 push up the locking pieces 8, 85 against the pressing force of the springs 11, 1V, that is, the force toward the salient magnetic pole 2 side of the movable core 3. The resistance force of the locking pieces 8, 8' against the movement of the coil F is set to 200 gr, and the attractive force for attracting the movable iron core 3 to the salient magnetic pole 2, that is, the current, is sequentially varied to increase the resistance of both coils F.
, 5, and the operation completion time was measured. The results are as shown in the table below. This shows the relationship between the composite force y, which is the result of adding the resistance force of the locking pieces 8 and 85 to the conventional spring FV and the spring of the present invention, and the gap G. This can also be confirmed from Figure 5.

Thus, in the present invention, the proximal end surface of the movable core 3, which is fitted through the one end wall 1b of the yoke 1 so that its tip can slide freely, is attached to the inner surface of the other end wall 1a of the yoke 1 or the other end wall 1a. A gear is placed on the front end surface of the salient magnetic pole 2 protruding from the inner surface of the salient pole, and a spring 4 is elastically mounted to act in a direction to separate the movable iron core 3 from the other end wall 1a. In a short-circuit current detection device in which a coil 5 is wound around the outer circumferential shell of a cylindrical coil frame 6 which is mounted so that the inner circumferential shell faces the outer circumferential shell of the iron core 3, the coil 5 is engaged with both sides of the tip of the movable iron core 3. A lock formed with grooves 7, r and attached to the outer surface of one end wall 1b of the yoke 1 so as to slide in a direction perpendicular to both side surfaces of the movable core 3 having the engagement grooves 7, r. Since the pieces 8 and 8' are fitted and pressed into the engagement grooves 7 and 75 by springs, there is an effect that when a short circuit current flows through the coil, the short circuit current can be quickly detected.

[Brief explanation of the drawing]

1 and 2 show a conventional short-circuit current detection device, FIG. 1 is a sectional view, FIG. 2 is an explanatory diagram of operation, and FIGS. 3 and 4 show an embodiment of the present invention. 3 is a sectional view, FIG. 4 is an explanatory diagram of operation, and FIG. 5 is an explanatory diagram of operation comparing the conventional one and the one of the present invention. 1 is York. 3 is a movable iron core, 4 is a spring, 5 is a coil, 7
, r engaging grooves, 8 and 85 are locking pieces, and 11 and 115 are fitted with springs.

Claims (1)

[Claims] 1. The proximal end face of the movable core 3, which is fitted through the one end wall 1b of the yoke 1 so that its tip can slide freely, is provided protruding from the inner surface of the other end wall 1a of the yoke 1 or the inner surface of the other end wall 1a. A spring 4 is elastically mounted to face the front end surface of the salient magnetic pole 2 with a gap therebetween and act in a direction to separate the movable iron core 3 from the other end wall 1a. The coil 5 is attached to the outer circumferential body of the cylindrical coil frame 6, which is attached so that the circumferential bodies face each other.
In a short-circuit current detection device formed by winding a movable core 3
One end of the yoke 1 is formed with engagement grooves 7, 7' on both sides of the distal end thereof, and slides in a direction perpendicular to both sides of the movable core 3 having the engagement grooves 7, 7'. The locking pieces 8, 8' attached to the outer surface of the wall 1b are connected to the engaging grooves 7, 8' by means of springs.
A short circuit current detection device formed by fitting and pressing 7'.