JP2864704B2 - Circuit breaker for wiring - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Industrial applications]

The present invention relates to a circuit breaker for protecting a wiring, and more particularly to a circuit breaker for easily selecting an overcurrent tripping method.

[Prior art]

The overcurrent trip device provided in the circuit breaker for wiring is known as a mechanical type or an electronic type. The mechanical overcurrent trip device detects the current using a bimetal or an electromagnet, and when an overcurrent flows, after a predetermined delay time due to these thermal deformation and the operation of attracting the movable iron piece,
Alternatively, it acts on the opening / closing mechanism instantaneously to open the blocking portion. On the other hand, the electronic overcurrent trip device always monitors the current signal detected by the current transformer with the electronic circuit, and when it is judged that the overcurrent state is present, the trip coil is delayed with a delay time corresponding to the magnitude of the current. To output a trip signal. The electronic type has features that the function of adjusting the operation characteristics can be easily realized as compared with the mechanical type, and various alarm functions and display functions can be added.

[Problems to be solved by the invention]

By the way, a circuit breaker provided with the above-mentioned mechanical overcurrent trip device (hereinafter referred to as a mechanical circuit breaker) and a circuit breaker provided with the above-mentioned electronic overcurrent trip device (hereinafter referred to as an electronic circuit breaker) Circuit breakers) are parts that cannot be shared, such as a main body case and a cover, and have unique processes in their manufacture. Therefore, conventionally, the user has to specify one of the methods to the manufacturer at the stage of ordering, and the method cannot be changed after the manufacturing. However, the mechanical type and the electronic type each have their own advantages, and there are cases where it is desired to selectively use them depending on the application. In particular, the electronic type can provide various additional functions, so that the user can use the mechanical type. If the wiring breaker can be easily changed to an electronic type, the wiring breaker will be extremely easy to use. SUMMARY OF THE INVENTION An object of the present invention is to provide a circuit breaker that can easily convert a mechanical circuit breaker into an electronic circuit breaker.

[Means for Solving the Problems]

In order to achieve the above object, the present invention has a built-in voltage tripping device or undervoltage tripping device, and a mechanical wiring breaker having a groove for mounting an inter-phase barrier in a case. A current transformer, a penetrating conductor penetrating through the current transformer and connected to a main circuit conductor of the mechanical circuit breaker, and an accident current passing through the penetrating conductor is detected via the current transformer, An electronic circuit for generating an overcurrent trip signal for a predetermined period of time corresponding to the magnitude of the current is housed in a mold case, and a unitized electronic overcurrent trip device is formed integrally with the mold case. The over-current trip signal is used to operate the voltage trip device or the under-voltage trip device by being fitted in the case groove so as to be detachable.

[Operation]

When an overcurrent flows through the main circuit conductor of a mechanical circuit breaker equipped with an electronic overcurrent trip device unit, the electronic overcurrent trip device determines the overcurrent condition and responds to the magnitude of the overcurrent. After that, the overcurrent trip signal is output. Therefore, the voltage trip device or the undervoltage trip device built in the mechanical circuit breaker is operated by this signal, and the circuit breaker is opened to protect the electric circuit. The mounting of the electronic overcurrent trip device on the mechanical circuit breaker uses the existing inter-phase barrier mounting groove in the case of the mechanical circuit breaker, and this is used to mold the electronic overcurrent trip device. It can be detached by inserting the engaging projection integrally formed on the case, so that the electronic overcurrent tripping device can be easily implemented as necessary without any modification to the standard case of the mechanical circuit breaker. Can be attached to In this case, if the mechanical overcurrent trip device is removed prior to mounting the electronic overcurrent trip device unit, the mechanical circuit breaker can be replaced with a normal electronic circuit breaker. Further, if the electronic overcurrent trip device unit is mounted while the mechanical overcurrent trip device is left, a circuit breaker using both types can be configured.

【Example】

Hereinafter, based on FIG. 1 and FIG. 2, an embodiment of the present invention in the case where an electronic overcurrent trip unit is mounted on a mechanical circuit breaker to constitute a circuit breaker for both types. An example will be described. Here, FIG. 1 (A) is a schematic longitudinal sectional view of a main part of the circuit breaker for wiring, FIG. 1 (B) is a plan view thereof, and FIG. 2 is an internal connection diagram of the circuit breaker of FIG. First, in FIG. 1, 1 is a circuit breaker for mechanical wiring,
Various components are housed in an outer box including a case 2 and a cover 3 of a mold resin. A load-side main circuit conductor 4 has one end having a load-side terminal plate, and the other end is connected to a movable contact (not shown) via a flexible conductor. 5 is a bimetal of the mechanical overcurrent trip device, 6 is also a fixed magnet, which are fixed together to the conductor 4 by rivets 7. Reference numeral 8 denotes a movable iron piece arranged to face the fixed magnet 6, and reference numeral 9 denotes a return spring. Reference numeral 10 denotes a voltage trip device, which is disposed on the opposite side of the bimetal 5 and the movable iron piece 8 of the mechanical overcurrent trip device with a trip crossbar 11a constituting a part of the opening / closing mechanism unit 11 interposed therebetween. On the other hand, reference numeral 12 denotes an electronic overcurrent trip device unit, in which a current transformer 16 mounted on a printed board 15, a through conductor 17 penetrating therethrough, and a current transformer in a mode case comprising a case body 13 and a cover 14. A printed circuit board 18 on which an electronic circuit for monitoring the current flowing through the through conductor 17 via the circuit board 16 and an overcurrent trip relay 19 controlled by the output of the electronic circuit are housed and unitized. The through conductor 17 is tightened from the back side to the case body 13 with the screw 20, one end 17a is a connection end with the load side terminal plate 4a of the circuit breaker body 1, and the other end 17b is a new load side terminal plate. I have. As shown in FIG. 1 (B), the case main body 13 is mounted on the circuit breaker main body 1 by fitting an engagement protrusion 13 a having a bulge at the tip into a groove 2 a of the same shape formed between the phases of the case 2. The connection end 17a of the through conductor 17 is fastened to the terminal plate 4a from the back side of the case 2 with a screw 21. Note that the groove 2a is provided as a standard equipment for mounting an inter-phase barrier. The cover 14 is screwed 22
Further, the case 2 is fastened to the case body 13 with screws 23 from the back side. As shown in FIGS. 1 (B) and 2, one end of the contact terminal of the overcurrent trip relay 19 is in one phase of the through conductor 17 and the other end is an electronic overcurrent trip unit. 12
Is connected to one end of the output terminal 24, and the other end of the output terminal 24 is connected to another phase of the through conductor 17. The leads of the voltage trip device 10 are connected to both ends of the output terminal 24. In such a configuration, when the current flowing through the conductors 4 and 17 becomes an overcurrent state, the electronic circuit that has detected this through the current transformer 16 drives the overcurrent trip relay 19 with a delay time corresponding to the current. A trip command is sent to the voltage trip device 10 to excite a trip coil (not shown). This allows
When the plunger 10a (FIG. 1 (A)) is sucked, the trip device 10 drives the trip crossbar 11a to the left in the figure, releases the locking mechanism of the opening / closing mechanism 11, and moves the movable contact 25.
(FIG. 2). Here, the mechanical and electronic overcurrent tripping devices share the respective operating characteristics, and when the rated breaking capacity or less, the tripping is performed by the electronic overcurrent tripping device. In the region, the movable iron piece 8 of the mechanical overcurrent tripping device is instantaneously attracted to the fixed magnet 6 against the return spring 9, and the trip crossbar 11a is moved to open and close the opening / closing mechanism unit 11. If the electronic overcurrent trip device becomes inoperable due to some abnormality, the trip crossbar 11a is pushed by the bending of the bimetal 5 heated by the heat of the conductor 4 due to Joule heat, and the trip operation is performed. Will be In the case of a circuit breaker having a built-in undervoltage tripping device instead of the voltage tripping device 10, a countermeasure is made by inverting the control signal for the overcurrent tripping relay 19. In the above-described embodiment, an example in which both mechanical and electronic overcurrent tripping devices are used is shown. However, the mechanical overcurrent tripping device may be removed and used as a simple electronic circuit breaker. It is.

【The invention's effect】

According to the present invention, a mechanical circuit breaker that is already in use is converted into an electronic circuit breaker using a built-in voltage trip device or undervoltage trip device, or Various alarm functions and display functions unique to the electronic overcurrent trip device can be easily added to
It is possible to provide flexibility between mechanical and electronic circuit breakers, which have hitherto been positioned completely differently.

[Brief description of the drawings]

FIG. 1A is a longitudinal sectional view of an essential part of an embodiment of the present invention.
FIG. (B) is a plan view thereof, and FIG. 2 is an internal connection diagram of the circuit breaker of FIG. 1 ... mechanical circuit breaker, 4 ... main circuit conductor, 10 ...
Voltage trip device, 11… Opening / closing mechanism section, 11a …… Trip crossbar, 12 …… Electronic overcurrent trip device unit,
16 ... current transformer, 17 ... through conductor.

Claims (1)

(57) [Claims] 1. A current transformer, which includes a voltage trip device or an undervoltage trip device, and a current-carrying device, which is provided on a load-side terminal of a mechanical circuit breaker having a groove for mounting an inter-phase barrier in a case. Penetrating conductor connected to the main circuit conductor of the mechanical circuit breaker, penetrating the circuit breaker, detecting a fault current passing through the through conductor via the current transformer, and corresponding to the magnitude of the fault current. After a predetermined period of time, an electronic circuit for generating an overcurrent trip signal is housed in a mold case and a unitized electronic overcurrent trip device is fitted into an engagement protrusion integrally formed in the mold case in a groove of the case. A circuit breaker for wiring, wherein the circuit breaker is detachably mounted and the voltage tripping device or the undervoltage tripping device is operated by the overcurrent tripping signal.