JPH0480491B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a breaker that combines a mechanical circuit breaking mechanism and a high-speed breaking circuit using a semiconductor switching element such as a thyristor.

[Background technology]

FIG. 1 is a front view showing the internal structure of a conventional general circuit breaker. In the same figure, 1 and 2
is a terminal fitting, which is inserted in the current path from the power source to the load. When the current flowing through the load is excessive, the detection coil 3 operates and the tripping mechanism 5 operates via the interlocking arm 4, thereby tripping the movable contact 6 and the fixed contact 7. A handle 8 is used to manually turn on and off the movable contact 6 and the fixed contact 7. Further, reference numeral 9 denotes an arc extinguishing device, which extinguishes the arc generated when the movable contact 6 and the fixed contact 7 are opened and separated. however,
In such a conventional example, since a mechanical tripping mechanism 5 is used, its response speed is determined by the mechanical movement and is usually about 10 msec. Therefore, if a circuit with a low withstand capacity, such as a semiconductor circuit, is used on the load side, there is a risk that the load will be destroyed due to the delay in the cut-off operation as described above.

[Purpose of the invention]

The present invention has been made in view of the above points, and combines a mechanical circuit interrupting mechanism and a high-speed interrupting circuit using a semiconductor switching element such as a thyristor to enable high-speed interrupting of load current. The object of the present invention is to provide a breaker that can protect a load with a low withstand capacity.

[Disclosure of the invention]

Hereinafter, the configuration of the present invention will be described with reference to illustrated embodiments. FIG. 2 is a circuit diagram of one embodiment of the present invention. In the figure, reference numeral 10 denotes a mechanical interrupting mechanism, which is comprised of a conventional circuit protector or breaker for protecting a thyristor. Reference numeral 11 denotes a thyristor for high-speed interruption, which bypasses the current supplied to the load by short-circuiting the load terminals T ₃ and T ₄ so that overcurrent is supplied to the load or overvoltage is applied to the load. This is to prevent this. Reference numeral 12 denotes a current detection resistor, and the voltage generated across this resistor 12 is input to an overcurrent detection circuit 13 and used for overcurrent detection. 15
An overvoltage detection circuit is provided to detect that an excessive voltage is applied to the load, and the overvoltage detection circuit 15 and the overcurrent detection circuit 14 constitute abnormality detection means. When the current flowing to the load side is excessive, a signal is input from the overcurrent detection circuit 13 to the gate drive circuit 14, and the thyristor 11 is triggered. The output of the overvoltage detection circuit 15 is also input to the gate drive circuit 14, and when the voltage output between the load terminals _T3 and _T4 is excessive, the overvoltage detection circuit 1
A signal is input from 5 to the gate drive circuit 14, and the thyristor 11 is triggered. Once triggered, the thyristor 11 remains in a conductive state, thereby causing a short circuit current to flow through the mechanical interrupting mechanism 10. This mechanical interrupting mechanism 10 includes a detection coil 3 for detecting overcurrent.
and a tripping contact 16 that is forcibly opened by the detection coil 3, and the tripping contact 1 is normally closed.
6 is closed, but when the thyristor 11 is turned on, the short-circuit current causes the trip contact 16 to open at a response speed of about 10 msec.
Therefore, the cutoff speed seen from the side of the power supply terminals T ₁ and T ₂ is determined by the mechanical delay of the mechanical cutoff mechanism 10 as before. However, when viewed from the side of the load terminals T ₃ and T ₄ , when the thyristor 11 is turned on, the thyristor 11 short-circuits between the loads T ₃ and T ₄ and cuts off the current supplied to the load. Since the current is bypassed so that the current is not supplied to the load, the cut-off speed is increased to about 10 μsec, which is the ON time of the thyristor 11.
FIG. 3 is a characteristic diagram showing the element. In the figure, the solid line shows the breaking characteristics of a conventional circuit protector for thyristor protection, the horizontal axis shows what percentage of the rated current the load current is, and the vertical axis shows what the breaking speed is in that case. sec. As is clear from the figure, when only a mechanical interrupting mechanism 10 such as a conventional circuit protector is used, the load current is 200% of the rated current.
% or more, the cutoff speed is approximately 10 msec. On the other hand, the characteristic indicated by the broken line in FIG. 3 is the cut-off characteristic when a high-speed cut-off circuit consisting of the thyristor 11 is added as in the example circuit of FIG. 2, and corresponds to the ON time of the thyristor 11.
It achieves a cut-off speed of approximately 10μsec. In FIG. 3, the broken line A indicates the overcurrent detection circuit 1.
An example is shown in which the operating point 3 is set at the point where the load current reaches 200% of the rated current, and the broken line B is
An example is shown in which the above operating point is set at the point where the load current reaches 500% of the rated current. As shown in the broken lines A and B, the operating point of the overcurrent detection circuit 13 is set to 3.
By making it variable within the range of P shown in the figure, the magnitude of the load current that interrupts the circuit can be freely set. Note that when the contact 16 of the mechanical cutoff mechanism 10 opens, the thyristor 1
Since the current flowing through thyristor 1 is cut off,
1 turns off and returns to a non-conducting state.

By the way, as for the configuration of the mechanical interrupting mechanism 10 used in the embodiment shown in FIG. 2, it is sufficient to use the conventional circuit protector or breaker for protecting the thyristor as described above. The case where the example breaker is used as is will be explained. FIG. 4 is a diagram showing the components of the breaker shown in FIG.
FIG. 5 is a sectional view of the breaker shown in FIG. 1.
6 to 8 are cross-sectional views of the breaker shown in FIG. 1 when the contacts are closed, when the overcurrent is cut off, and when the short circuit current is cut off. In each of the above figures, a protective sensor 17 for detecting overcurrent or short-circuit current includes a magnetic yoke 18 having a substantially rectangular cross section and a longitudinal cylinder 19. The first cylinder 19 includes a lower cylinder body 20 made of a non-magnetic material, preferably brass, with an open upper end, and an upper cylinder body 20 made of a non-magnetic material, preferably plastic, with open ends and a slightly larger diameter than the lower cylinder body 20. A cylinder body 21 is provided,
Both cylinder bodies 20, 2 are provided in the opening at the upper end of the lower cylinder body 20 and the opening in the upper cylinder body 21.
A magnetic head 22 is fitted to interconnect the two. Further, a viscous fluid, preferably silicone oil, is sealed inside the lower cylinder body 20, and an oil plunger 23 made of a magnetic material and the oil plunger 23 are normally connected to the lower cylinder body 20.
Coil spring 2 that presses toward the inner surface of the lower end of
4 is housed therein, passes through the center of the lower side 25 of the yoke 18, and is fixed to the lower side 25 with a portion protruding downward. Further, the upper cylinder body 21 is equipped with an operating plunger 26 made of a magnetic material, and the operating plunger 26 has a head portion 2.
A rod portion 28 to which a cylinder 7 is fixed is provided integrally, and the rod portion 28 is connected to the upper cylinder body 21.
It is provided so as to be able to extend outward from the upper end of the tapered mouth. The tapered upper end of the upper cylinder body 21 is fitted into a circular hole having a lip 30 in the upper side 29 of the yoke 18 and is fixed therein.

Further, a detection coil 3 is wound around the cylinder 19 substantially over the entire longitudinal direction thereof, and one of the lead-out ends 31 and 32 of the detection coil 3 extends from one side 33 of the yoke 8. It is connected to a lead wire 34 which penetrates substantially horizontally and protrudes and has sufficient flexibility, and the other end is led out from the open side of the yoke 18 and bent downward, and is connected to a terminal of the circuit breaker. It is fixed to the metal fitting 2. Furthermore, the spring force of a coil spring, which will be described later, is normally applied to the actuating plunger 26 so as to displace it upward, and the upper surface of the actuating plunger 26 is normally provided in contact with the inner surface of the upper end of the upper cylinder body 21. ing.

A frame 35 for supporting a manual opening/closing mechanism including a trip mechanism is integrally provided at the upper end of the side portion 33 of the yoke 19 and extends substantially in the direction in which the upper side portion 29 extends. The frame 35 includes a short frame portion 36 and a long frame portion 37 that extend vertically and parallel to each other. In the short frame portion 36, shaft holes 39 and 40 are formed at the most extreme edge portion 38 and at an upper corner near the rear edge, respectively, and a shaft hole 41 is formed near the rear edge below the shaft hole 40. It is perforated. On the other hand, the long frame part 37 has a shaft hole 43 in an enlarged part 42 provided at a position corresponding to the ear part 38 of the short frame part 36, and corresponds to the shaft holes 40, 41 of the short frame part 36 near the rear edge. Shaft holes 44 and 45 are drilled at the positions shown in FIG. Further, an inverted L-shaped sliding window 46 is formed in the long frame portion 37 with an arcuate edge 47 on one side, and the tip portion is bent at a substantially right angle. Further, a locking portion 49 is provided on the upper edge of the bent portion 48, and a small disk-shaped arc traveling ear portion 50 is provided on the lower edge in the horizontal direction.
has been extended.

Cylindrical lower part 51 of the handle 8 of the manual opening/closing mechanism
A shaft hole 52 is bored in the center, and
A protruding portion 54 having a through hole 53 is provided on a part of the circumferential surface. The handle 8 has short and long shafts 5 held in shaft holes 39 and 43 of the long frame parts 36 and 37.
5 into the shaft hole 52, the frame 35
is rotatably supported. Further, one leg portion 57 of a U-shaped link pin 56 is inserted into the through hole 53 of the enlarged portion 54, and the free end of the leg portion 57 is connected to an L-shaped sliding window of the long frame portion 37. 46 and is movable along an arcuate extension 47. The other leg side 58 of the link pin 56 is inserted into the shaft holes 62, 63 of the ears 60, 61 provided oppositely to the link arm 59, and its free end is loosely engaged with the sliding window 46. It is disposed movably within the other side.

The link arm 59 itself has an inverted U-shaped base 64 when viewed from the end, and the base 64 has an insertion window 65.
is formed. The ear portions 60 and 60 extend vertically and parallel to each other downward from the front end of the base portion 64.
61 is provided to protrude upward, and arm portions 66 and 67 are integrally extended, and shaft holes 68 and 69 are bored in the distal ends of the arm portions 66 and 67, respectively. Further, from the lower edge of one arm part extends a kicking tongue part 70 which is bent into an L-shape and slightly inclined upward with respect to the vertical direction, and from the upper edge thereof is bent into an L-shape and is substantially A horizontally extending stop ear 71 is provided. A support shaft 72 is held in the shaft holes 68 and 69 at the tips of both the arm portions 66 and 67, and the support shaft 72 is connected to an angle-shaped movable contact 73 connected to one end of the detection coil 3 via the lead wire 34. Shaft hole 74
The link arm 5 is inserted through the link arm 5.
A movable contactor 73 is pivotally supported to 9. Above the shaft hole 74 of the movable contact 73, an enlarged portion 76 having a locking hole 75 is provided to protrude upward, and a movable contact 6 preferably made of a highly conductive contact material is provided at the lower edge of the tip. is permanently installed.

The movable contact 6 of the movable contact 73 is arranged so as to be able to come into contact with a fixed contact 7 attached to a fixed contact 77 disposed below the movable contact 73 and preferably made of a highly conductive material. The fixed contact 77 itself has an arc running portion 79 that extends downward from one leg of the U-shaped portion 78 to which the fixed contact 7 is fixed, and faces the arc running ear portion 50 of the frame 35.
is extended, is bent into an L-shape from the other leg of the U-shaped portion 78, and is integrated with the terminal fitting 1.
has been extended.

To further explain the trip mechanism in detail, the interlocking arm 4 of the trip mechanism is pivotally supported by a support shaft 82 held in the shaft holes 40, 44 of the frame 35. The interlocking arm 4 includes a base portion 84 having a notch 83 that engages the head portion 28 of the protection sensor 17, and a pair of arm portions 85 and 86 extend perpendicularly and parallel to each other from the front end of the base portion 84. Each of the arm portions 85,
The support shaft 82 is inserted through the shaft holes 87 and 88 bored in the shaft 86, and the interlocking arm 4 is pivotally supported on the frame 35 as described above. Also, one arm portion 85 has an L
A kicking leg portion 89 is provided in a protruding manner, which is bent into a letter shape and extends downward, and is capable of striking the kicking tongue portion 70 of the link arm 59 when the interlocking arm 4 rotates. Further, in the support shaft 82, a latch metal fitting 90 which is L-shaped when viewed from the side and operates integrally with the interlocking arm 4 is attached to the shaft hole 9.
1 and 92, and the latch fitting 90
One side part is provided as an arm part 93 that can come into contact with the lower surface of the base 84 of the interlocking arm 4, and the other side part extends downward and enters the insertion window 65 of the link arm 59 and is locked to the edge thereof. A foot portion 95 having a hook portion 94 is provided.

On the other hand, a coil spring 96 is wound around the support shaft 55 of the handle 8, and the coil spring 96 is guided by a semi-annular guide 8a at the lower part 51 of the handle 8, and one end of the coil spring 96 is connected to the sliding window 46.
The other end is locked to the leg side 57 of a U-shaped link pin 56, and the contact is always opened in the direction of opening of the contact with respect to the handle 8, that is, clockwise in FIG. It provides the turning force. Also frame 3
One end of a return spring 97 is locked to the locking portion 49 at the tip of the long frame portion 37 of 5, and the other end of the return spring 97 is locked to the locking hole 75 of the movable contact 73.
The movable contact 73 is always applied with a force in the direction of separating from the fixed contact 77. Further, an interlocking arm spring 98 and a latch spring 99 are wound around the support shaft 82 of the interlocking arm 4. One end of the interlocking arm spring 98 is attached to the lower surface of the base 84 of the interlocking arm 4, and the other end is attached to the shaft of the frame 35. It is locked to a locking shaft 100 held in the holes 41 and 45, and always acts on the interlocking arm 4 in the counterclockwise direction in FIG. 1, that is, in the direction of pulling up the operating plunger 26. Further, one end of the latch spring 99 is attached to the locking shaft 100, and the other end is attached to a suitable place on the frame 35, for example, on the long frame portion 37.
The latch fitting 90 functions to always be latched in the counterclockwise direction in FIG. 1, that is, to the link arm 59.

An arc extinguisher 9 is disposed between the arc running ear portion 50 of the frame 35 and the arc running portion 79 of the fixed contact 77. The arc extinguishing device 9 includes a recess 102 through which the tip of the movable contact 73 can pass, and a large number of deionization grids 10 spaced apart from each other with small gaps.
3. In addition, the deion grid 10
The third group is held by both side plates 104 and 105, and an end plate 106 fixed to the side plates 104 and 105 is provided at the edge thereof. Said end plate 106
An arc gas outflow window 107 is formed in the arc gas outflow window 107, and a deion grid 10 is formed in the center of the outflow window 107.
A direct release prevention plate portion 108 is provided at a location corresponding to the recess 102 of No. 3.

Furthermore, the operation of this circuit breaker will be explained. The handle 8 of the manual opening/closing mechanism is now in the position shown in Figure 1 or Figure 5.
When is rotated clockwise in the figure,
One leg side 57 of the link pin 56 is the sliding window 46
The other leg side 58 is located at the upper end of the sliding window 46 along the arcuate edge 47 of the slide window 46, and the spring force of the return spring 97 is also applied, so that the link arm 59 and Movable contact 7
3 is moved up. Therefore, the movable contact 6 of the movable contact 73 is separated from the fixed contact 7 of the fixed contact 77, that is, the contact is in an open state. In this case, the link arm 59 is prevented from moving upward more than necessary by a protrusion (not shown) of the casing. On the other hand, the handle 8 is rotated from the position shown in FIG. 1 or 5 to the position shown in FIG. If so, the link pin 56 inserted through the through hole 53 of the enlarged portion 54 of the lower part of the handle 51
The position of one leg side 57 of the handle is
5 and the other leg side 52 of the link pin 56, the handle 8 overcomes the spring force of the coil spring 96 and the return spring 97.
is stopped and held in the counterclockwise rotation position. As a result, one leg side 5 of the link pin 56
7 reaches the lower part of the arcuate edge 47 of the sliding window 46, and the other leg side 58 reaches the lower part of the other side of the sliding window 46.
That is, since the link pin 56 is in a substantially vertical state and the hook part 94 of the latch fitting 90 is engaged with the edge of the engagement window 65 of the link arm 59, The movable contacts 73 connected to the link arm 59 move downward and tilt forward, so that the movable contact 6 contacts the fixed contact 7, that is, the contact is in a closed state. In this case, the electric path is formed by the terminal fitting 2, the detection coil 3, the lead wire 34, the movable contact 73, the movable contact 6, the fixed contact 7, the fixed contact 77, and the terminal fitting 1.

Furthermore, if an excessive current, for example, a current 1.15 times the rated current, continues to flow when the contacts shown in FIG. It is relatively slowly attracted to the magnetic head 22 against the viscosity of the oil sealed in the lower cylinder body 20. This provides a time delay effect and does not respond to an excessive current flowing for a relatively short period of time, such as a starting current, even if it is detected. When the oil plunger 23 is attracted to the magnetic head 22, the permeance of the magnetic circuit via the yoke 18 increases, and the operating plunger 26, which is always placed in the upward movement position, is moved to the upper position by the interlocking arm spring 98 via the interlocking arm 4. 7. Magnetic head 2 as shown in figure 7.
It is adsorbed by 2. Accordingly, the interlocking arm 4 and the latch fitting 90 rotate around the support shaft 82, and the hook part 94 of the latch fitting 90 comes off the edge of the locking window 65 of the link arm 59, and the kicking leg part 8 of the interlocking arm 4
9 hits the kicking tongue portion 70 of the link arm 59. Therefore, a strong starting force is applied to the link arm 59 by the lever strike, and the rotational force of the link arm 59 is rapidly increased. Together with the tensile force 97, the movable contact 73 is rapidly separated from the fixed contact 77. At this time, the arc generated when the contact is opened is driven toward the arc extinguishing device 9 by the electromagnetic driving force generated by the current flowing through the fixed contact 77 or the movable contact 73, and is extinguished. When the movable contactor 73 moves upward, the upper tip of the movable contactor 73 is positioned very close to the frame 35, and after the contact is opened, the frame 35 having the arc running ear portion 50 and the yoke integrated with the frame 35 An electrical path can be formed via 18.

Furthermore, when the contact shown in FIG. 6 is closed, when a short-circuit current, for example, a current two or three times the rated current flows, the excitation force by the detection coil 3 is extremely large.
Only actuating plunger 26 immediately engages magnetic head 22.
It begins to be attracted towards. At this time, interlocking arm 4
At the same time, the latch metal fitting 90 rotates around the support shaft 82, and the hook part 94 of the latch metal fitting 90 disengages from the edge of the locking window 65 of the link arm 59, and the kicking foot part 89 of the interlocking arm 4 kicks the link arm 59. Hit the tongue 70. Therefore, as described above, this impact imparts a so-called strong starting force to the link arm 59, and the movable contact 73 is rapidly separated from the fixed contact support 77 as shown in FIG. Other actions are the same as when excessive current is detected.

〔Effect of the invention〕

As described above, the present invention includes a mechanical interrupting mechanism that rapidly forcibly opens the tripping contact when the detection coil detects that the current supplied to the load becomes at least excessive, and Abnormality detection means for detecting overcurrent supplied and overvoltage applied to the load is provided between the mechanical cutoff mechanism and the load terminal, and in the event of an abnormality, the output of the abnormality detection means short-circuits the load terminals. The semiconductor switching element conducts so as to cause an excessive current to flow through the detection coil, so that in the event of an abnormality such as when the load current is excessive or the load voltage is excessive, the semiconductor switching element does not conduct. The current supplied to the load can be bypassed via this semiconductor switching element, thereby quickly stopping excessive load current from being supplied to the load or excessive load voltage from being applied. In addition, when the semiconductor switching element conducts in this way, a large current flows through the detection coil through the semiconductor switching element, allowing the mechanical interrupting mechanism to forcibly open the tripping contact. A semiconductor switching element can compensate for the response delay that occurs when a mechanical cutoff mechanism mechanically operates and responds.In other words, when the semiconductor switching element operates, the power is cut off from the perspective of the load. Therefore, high-speed shutdown is possible, and even when the load is a circuit with a low withstand capacity such as a semiconductor circuit, there is an advantage that the load will not be destroyed.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the internal structure of a conventional general circuit breaker, FIG. 2 is a circuit diagram of an embodiment of the present invention, FIG. 3 is an explanatory diagram of the same operation, and FIG. An exploded perspective view showing the components of the illustrated circuit breaker;
Figure 5 is a sectional view of the circuit breaker shown in Figure 1;
The figure is a cross-sectional view of the same circuit breaker when the contacts are closed, Figure 7 is a cross-sectional view of the same circuit breaker when the circuit breaker is in overcurrent interrupting operation, and Figure 8 is a cross-sectional view of the same circuit breaker when the above circuit breaker is in operation to interrupt short circuit current. FIG. 3 is a detection coil, 10 is a mechanical cutoff mechanism, 11
is a thyristor, 12 is a resistor, 13 is an overcurrent detection circuit, 14 is a gate drive circuit, 15 is an overvoltage detection circuit, 16 is a tripping contact, T ₁ and T ₂ are power terminals,
T ₃ and T ₄ are load terminals.

Claims (1)

[Claims] 1 Mechanical cutoff mechanism that rapidly forcibly opens the trip contact when the detection coil detects that the current supplied to the load has become at least excessive, and the overcurrent supplied to the load and the load. an abnormality detection means for detecting an overvoltage applied to the above, and is provided between the mechanical cutoff mechanism and the load terminal, and in the event of an abnormality, the output of the abnormality detection means causes the load terminals to be electrically connected so as to short-circuit the load terminals. A breaker comprising: a semiconductor switching element that causes the above-mentioned excessive current to flow through a detection coil.