JP2501441B2 - Circuit breaker for wiring - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a circuit breaker having a contact device that is opened when an excessive current passes through a main circuit.

[Background Art] In a conventional circuit breaker for a wiring, when a short-circuit current passes through a main circuit, a solenoid inserted in the main circuit is driven to open a contact device. In some cases, when an overcurrent larger than the current passes through the main circuit, the heater inserted in the main circuit heats the bimetal so that the contact device is opened by utilizing the curvature of the bimetal. However, when the heater and the bimetal are combined, there is a problem that it is difficult to adjust how much current the contact device is opened.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to make it possible to easily adjust the magnitude of a main circuit passing current when opening a contact device. An object of the present invention is to provide a circuit breaker equipped with a current detection device.

Disclosure of the Invention (Example 1) In the following example, an example in which the technical idea of the present invention is applied to a three-pole type circuit breaker for wiring will be shown.

As shown in FIG. 4, the wiring breaker includes an overcurrent detection device 1 that is driven when an overcurrent passes through the main circuit, and a trip device 2 that performs a trip operation when the overcurrent detection device 1 is driven. A contact device 3 that is momentarily opened when the trip device 2 performs a trip operation, and an arc extinguishing device 4 that extinguishes an arc generated when the contact device 3 is opened are installed in a body 5. The handle 56 that is interlocked with the trip device 2 projects upward and downward from the upper surface of the body 5. The overcurrent detection device 1, the contact device 3, and the arc extinguishing device 4 are provided for each pole, and the trip device 2 is provided so as to be shared by the poles. An exhaust plate 51 that connects the inside and outside of the body 5 is fitted to the side surface of the body 5 on the arc extinguishing device 4 side.

As shown in FIG. 1 and FIG. 2, the overcurrent detection device 1 is a solenoid and includes a main coil 11a, a sub coil 11b,
It is composed of a yoke 12, a plunger 13, a return spring 14, and a plunger 15. The main coil 11a is a coil bobbin 16a wound with a braided wire 17a that is insulation-coated. One end of the braided wire 17a is connected to a terminal plate 52 on the power supply side, and the other end of the braided wire 17a is connected to a contact device 3 described later. It is connected to the movable contact 31. At the center of the coil bobbin 16a, a rectangular through hole 18a through which the lower end of the plunger 13 is inserted is formed. On the other hand, the sub-coil 11b is formed by winding a wire 17b that is insulated and coated on the coil bobbin 16b, and the coil bobbin 16b is formed with a rectangular through hole 18b through which the lower end of the plunger 13 is inserted. A screw hole 54 into which a terminal screw 53 is screwed is formed in the central portion of the terminal plate 52. The yoke 12 is formed by bending a magnetic plate into a substantially S shape, and rectangular through holes 18c and 18d through which the plunger 13 is inserted are formed in the upper horizontal piece and the middle horizontal piece. Has been done. Further, the main coil 11a and the sub-coil 11b are mounted between the middle horizontal piece and the lower horizontal piece with the main coil 11a facing downward. A bush 15 made of a non-magnetic material is attached to a through hole 18d formed in a horizontal piece in the middle of the yoke 12. The plunger 13 is made of a magnetic material,
A hooking piece 13b is formed on the upper end portion, and a spring storage recess 13a that is opened to the side is formed on the upper and lower intermediate portions.
The vertical width of the spring accommodating recess 13a is set to be approximately equal to the distance between the upper horizontal piece and the middle horizontal piece of the yoke 12. A return spring 14 is mounted in the spring storage recess 13a. However, insert the plunger 13 into the yoke 12 with the bush 15 attached,
The return spring 14 is provided with a spring accommodating recess 13a in a state where the spring accommodating recess 13a is made to correspond between the upper horizontal piece and the middle lateral piece of the yoke 12.
If you attach it to the side of
The upper horizontal piece of 12 and the bush 15 are elastically contacted with each other, and when the plunger 13 moves up and down, the return spring 14 is compressed and a return force acts on the plunger 13. When the main coil 11a and the sub coil 11b are not energized, the lower end of the plunger 13 is located above the lower horizontal piece of the yoke 12 and is inserted into the main coil 11a and the sub coil 11b at the same time. It is in the state of being Where the main coil 11a
When a large current such as a short-circuit current passes, the magnetic force generated in the main coil 11a causes the plunger 13 to move downward against the spring force of the return spring 14. The magnitude of the current that the plunger 13 moves downward when passing through the main coil 11a is adjusted by the spring constant of the return spring 14. The sub-coil 11b is set so that the plunger 13 is moved downward by the magnetic force generated in the sub-coil 11b when a voltage of about the rating of the main circuit is applied. The overcurrent detection device 1 is provided for each pole and operates independently of each other.

Here, the power supply is a three-phase AC, and the circuit breaker for wiring is 3
It has a pole configuration, and the one pole sub coil 11b is
As shown in FIG. 3, both ends are connected to the overcurrent detection circuit section 7 through the normally closed contacts NC of the relay 6 arranged in the body 5. The auxiliary coil 11b is a normally open contact NO of the relay 6.
Connected to the power supply via. The overcurrent detection circuit unit 7 is a circuit that outputs an overcurrent detection signal when the input voltage exceeds a predetermined value, and a resistor R that converts the current flowing through the sub coil 11b into a voltage is connected to the input end. . The overcurrent detection signal is input to the switching element SW such as a transistor,
It controls the excitation and de-excitation of the coil 6a of the relay 6 built in the body 5. Relay 6 coil 6a and switching element
A power supply circuit 8 including a rectifier circuit connected to a power supply and a constant voltage power supply is connected to a series circuit with the SW. Therefore, when the switching element SW receives the overcurrent detection signal and becomes conductive, the coil 6a of the relay 6 is supplied with power from the power supply circuit 8 and is excited. With the above configuration, by appropriately setting the input voltage required for the overcurrent detection circuit unit 7 to output the overcurrent detection signal, a current below the rated value can be applied to the main coil 11
When passing through a, the normally closed contact NC of the relay 6 is closed and the auxiliary coil 11b can be set to a state for detecting an overcurrent. On the other hand, when the output of the sub coil 11b magnetically coupled to the main coil 11a detects that an overcurrent passes through the main coil 11a, an overcurrent detection signal is output from the overcurrent detection circuit unit 7, As shown in FIG. 4, the open / closed state of the contact of the relay 6 is reversed and the auxiliary coil 11b
Is connected to the power supply, the sub coil 11b is excited, and as a result, the plunger 13 is attracted by the sub coil 11b and moves downward. That is, when an overcurrent larger than the rated current and smaller than the short-circuit current passes,
When the sub coil 11b is excited, the contact device 3, which will be described later, is set to open. Here, there is a slight time delay between the excitation of the coil 6a of the relay 6 and the driving of the normally closed contact NC and the normally open contact NO. There is a time delay. Further, it goes without saying that the overcurrent detection circuit unit 7, the power supply circuit 8, the relay 6, and the switching element SW are installed in the body 5. Further, in the above-mentioned example, the contact device 3 having three poles is opened for the three-phase power source, but the contact device 3 having (N-1) poles is used for the N-phase power source.
Should be opened.

The trip device 2 includes a holding frame 21 fixed at a fixed position of the body 5, and the holding frame 21 has a latch link 22, a locking lever 23, a cradle 24, a first link 25, a second link 26, And each link of the handle link 27 and each link 22 to 27 is held on the frame 21 or each link 22 to 27.
Link pins 22a to 25a that connect the two to each other, a pair of compression springs 22b and 23b that bias the latch link 22 and the locking lever 23 in a fixed rotation direction, and a tension spring 27b that biases the handle link 27. Are installed. Further, the interlocking bar whose both axial ends are rotatably held by the body 5
28 is provided, and the overcurrent detecting device 1 and the latch link 22 are interlocked via the interlocking bar 28. Here, the interlocking bar 28 is coupled to the plunger 13 so as to rotate when any one of the plungers 13 of the overcurrent detecting devices 1 of each pole moves downward. The trip device 2 is operated by operating the handle 56 projecting on the upper surface of the body 5 (operation of tilting to the left side in FIG. 4) to compress the compression springs 22a and 23b and the tension spring 2.
7b is configured to maintain a balanced state with accumulated power, and the plunger 13 of the overcurrent detection device 1 is the main coil.
When it moves downward due to the excitation of 11a or the sub coil 11b, the interlocking bar 28 rotates, the equilibrium state of the trip device 2 collapses, and the accumulated power is rapidly released.

The contact device 3 includes a movable contact 31 having a movable contact 32,
The crossbar 35 that holds the movable contact 31 and the crossbar 35
A contact pressure spring 33 interposed between the movable contactor 31 and the movable contactor 31, and a fixed contact 34 integrally provided with the arc extinguishing device 4 described later. One end of a braided wire 17a forming the main coil 11a is connected to the movable contactor 31. The cross bar 35 is formed of an insulating material such as synthetic resin, and both axial ends thereof are axially supported at fixed positions on the inner peripheral surface of the body 5, so that one end of the movable contact 31 can be vertically swung. Hold it. The movable contact 31 has the second link 26 of the trip device 2 at the intermediate portion.
The contact device 3 is closed when the trip device 2 accumulates power, and opens when the power accumulated in the trip device 2 is released.

A fixed contact 34, which constitutes a contact with the movable contact 32, is provided on the upper surface of a fixed contact plate 41 of the arc extinguishing device 4, and an arc extinguishing grid device 42 is arranged at one end of the fixed contact plate 41.
Grid device with fixed contact 34 sandwiched between fixed contact plates 41
One end of an arc drive coil 43 is connected to the end opposite to 42. The arc drive coil 43 is bent downward in a substantially U shape, and is arranged so that the fixed contact 34 is located at a corresponding position between the two leg pieces. The other end of the arc drive coil 43 is connected to the terminal plate 55. A terminal screw 56 is screwed onto the terminal board 55. The arc-extinguishing grid device 42 is a device in which a plurality of grid plates 44, which are conductive plates and are arranged in parallel with a small space in the vertical direction, are held by a holding frame 45 made of an insulating material. However, when the movable contact 32 and the fixed contact 34 are opened to generate an arc, the arc is directed toward the arc-extinguishing grid device 42 by the electromagnetic force acting between the arc and the magnetic field generated around the arc drive coil 43. The arc introduced into the arc extinguishing grid device 42 is radiated by the grid plate 44 to be rapidly extinguished.

With the above configuration, the main electric path that passes through the terminal plate 52, the main coil 11a, the movable contact 31, the movable contact 32, the movable contact 34, the fixed contact plate 41, the arc drive coil 43, and the terminal plate 55 is formed. .

[Advantages of the Invention] As described above, the present invention provides an overcurrent detection device that operates by detecting the passage of an excessive current through the main circuit, and a main contact that opens in response to the operation of the overcurrent detection device. In a circuit breaker provided with a contact device inserted in an electric circuit, an overcurrent detection device includes a main coil inserted in a main electric circuit together with a contact device, a sub coil magnetically coupled to the main coil, a main coil, and A plunger that is made of a magnetic material that is inserted into the sub coil so that it can move back and forth, and that opens the contact device when the main coil and the sub coil are pulled in; and a return that urges the plunger to project from the main coil and the sub coil. Inserted between the sub coil and the over current detection circuit section that generates an over current detection signal when the current induced in the sub coil by the current passing through the spring and the main coil exceeds a predetermined value. It It has a normally closed contact and a normally open contact inserted between the auxiliary coil and the power supply, and the relay whose open / closed state is inverted by the overcurrent detection signal is provided, and the current passing through the main coil is short-circuited. At least the magnetic force generated in the main coil when the current is larger than the current that generates the overcurrent detection signal, and the magnetic force generated in the subcoil when the subcoil is connected to the power supply by the overcurrent detection signal. The plunger is pulled into the main coil and the sub coil against the spring force of the return spring by either one, and the current passing through the main circuit is detected by the sub coil.
When an overcurrent is detected, the power supply is connected to the sub coil in response to the overcurrent detection signal output from the overcurrent detection circuit unit. This has the advantage that it is possible to easily adjust electrically whether the contact device is opened by the current of. When the rated current is passing through the main circuit, an overcurrent is detected by the subcoil magnetically coupled to the main coil, and it is detected by the subcoil that overcurrent is passing through the main circuit. Since the sub-coil is excited to drive the plunger, the sub-coil can be used for both the detection of the overcurrent and the driving of the plunger, and there is an advantage that the size can be reduced as a whole.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an overcurrent detecting device used in an embodiment of the present invention, FIG. 2 is a sectional view of the same, FIG. 3 is a circuit diagram of the same, and FIG. FIG. 5 is a sectional view showing an embodiment of the present invention. 3 is a contact device, 6 is a relay, 7 is an overcurrent detection circuit section, 11
a is a main coil, 11b is a sub coil, 13 is a plunger, 14 is a return spring, NC is a normally closed contact, NO is a normally open contact, and SW is an external contact.

Claims (1)

(57) [Claims] 1. An overcurrent detection device that operates by detecting that an excessive current has passed through a main circuit, and a contact device inserted in the main circuit that is opened in response to the operation of the overcurrent detection device. In a circuit breaker equipped with, the overcurrent detection device is inserted into the main coil along with the contact device, the auxiliary coil magnetically coupled to the main coil, and the main coil and the auxiliary coil so that they can move back and forth. Made of a magnetic material that opens the contact device when it is drawn into the main coil and the sub coil, a return spring that biases the plunger in a direction to make it protrude from the main coil and the sub coil, and passes through the main coil. The overcurrent detection circuit section that generates an overcurrent detection signal when the current induced in the subcoil exceeds a predetermined value due to the current, and the normally-closed contact and the subcircuit inserted between the subcoil and the overcurrent detection circuit section. Ko Equipped with a relay that has a normally open contact inserted between the power supply and the power supply and whose open / closed state is reversed by the above-mentioned overcurrent detection signal, and the current passing through the main coil is detected as an overcurrent. The plunger returns due to at least one of the magnetic force generated in the main coil when the current is larger than the signal generating current and the magnetic force generated in the sub coil when the sub coil is connected to the power supply due to the overcurrent detection signal. A circuit breaker, which is drawn into the main coil and the sub coil against the spring force of the spring.