JP2592004B2 - Overcurrent trip device for circuit breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to an electronic overcurrent trip device used for a circuit breaker such as a wiring breaker.

[Prior art]

The overcurrent tripping device constantly monitors the current passing through the circuit breaker, and when this current becomes an overcurrent state, issues a command to trip the circuit breaker. As the overcurrent trip device, there are known a mechanical type in which an overcurrent state detecting unit is formed by a bimetal or an electromagnet, and an electronic type in which an overcurrent state is formed by an electronic circuit. An electronic overcurrent trip device is a current transformer that detects a current flowing through a circuit breaker, an electronic circuit that monitors a current signal of the current transformer, and a drive current that is output from the electronic circuit due to occurrence of an overcurrent. It is composed of a trip coil unit that operates with a motor. It has features such as easy adjustment of rated current and tripping operation characteristics as compared with a mechanical type, and addition of various alarm and display functions. FIG. 4 shows a schematic configuration of a circuit breaker provided with the above-mentioned electronic overcurrent trip device.
A power supply side terminal 3, fixed contacts 4, movable contacts 5, overcurrent trip device 6, load side terminal 7, switching mechanism 8, arc extinguishing chamber 9 Are stored. The overcurrent trip device 6 includes a current transformer 11 through which a conductor 10 connecting the movable contact 5 and the terminal portion 7 passes, an electronic circuit (not shown) mounted on a printed board, and a trip coil unit 12. When it is determined that the current detected by the flower 11 is in an overcurrent state, the output of the electronic circuit causes the trip coil unit 12 to act on the opening / closing mechanism section 8 to separate the movable contact 5.

[Problems to be solved by the invention]

By the way, since the configuration of an overcurrent trip device is different between a mechanical type and an electronic type, it is conventionally a circuit breaker using a mechanical overcurrent trip device (hereinafter referred to as a mechanical circuit breaker). A circuit breaker using an electronic overcurrent trip device (hereinafter, referred to as an electronic circuit breaker) is configured using a dedicated outer box, and is assembled on separate lines. However, if the circuit breaker body can be shared between the mechanical type and the electronic type, parts such as the case 1 and the cover 2 can be shared, and the assembly line can be clarified. This is advantageous. In particular, since electronic circuit breakers can be multi-functional, various functions are required depending on the purpose of use, and it is inevitable that the price will be high, but the electronic circuit breaker uses the circuit breaker body of the mechanical circuit breaker. If a circuit breaker can be configured, the cost can be easily reduced. In view of the above, an object of the present invention is to provide an overcurrent trip device for a circuit breaker in which an electronic circuit breaker can be configured by sharing a mechanical circuit breaker and a circuit breaker body. is there.

[Means for Solving the Problems]

The present invention provides, in a mold case that can be mounted on the load side of a circuit breaker body, a conductor having one end connected to the load-side terminal portion of the circuit breaker body and the other end serving as a terminal portion, and a current flowing through the conductor. A current transformer that detects the current and an electronic circuit that monitors the current signal of the current transformer and outputs a trip signal when the current flowing through the conductor is determined to be in an overcurrent state,
A trip coil unit that receives the output of the electronic circuit and opens and closes the switching mechanism of the circuit breaker body is disposed in the circuit breaker body.

[Operation]

The part of the electronic overcurrent tripping device excluding the trip coil unit is housed in a special molded case, and mounted on the load side of the circuit breaker body that is shared with the mechanical circuit breaker.
The terminal is used as a new load-side terminal. Then, instead of the mechanical overcurrent trip device, a trip coil unit for operating the switching mechanism is disposed in the circuit breaker body. Thus, electronic circuit breakers having various functions can be freely configured using the circuit breaker body prepared as a standard mechanical circuit breaker.

【Example】

1 to 3 show an embodiment of the present invention. FIG. 1 is a side view of a cross section of a main part of a circuit breaker provided with an overcurrent trip device of the present invention, and FIG. 2 is a main part. FIG. 3 is a plan view and FIG. 3 is a perspective view of a main part showing a trip characteristic setting unit. Note that parts corresponding to those in the conventional example are denoted by the same reference numerals. In FIGS. 1 and 2, reference numeral 13 denotes a main body of a circuit breaker configured as a mechanical type, and reference numeral 14 denotes a load-side terminal portion. On the other hand, reference numeral 15 denotes a molded case which is mounted on the load side of the circuit breaker main body 13 and accommodates a portion of the electronic overcurrent release device excluding the trip coil unit.
And a cover 17. The case 16 includes a current transformer 11 mounted on a printed circuit board 17, a conductor 10 passing through the current transformer 11, and a printed circuit board 18 mounted with an electronic circuit for monitoring a current flowing through the conductor 10 via the current transformer 11. And 19 are stored. The conductor 10 is fastened from the back to the case 16 with the screw 20, one end 10a is a connection end to the terminal portion 14 of the circuit breaker main body 13, and the other end 10b is a new load side terminal portion. As shown in FIG. 2, the case 16 of the overcurrent tripping device is mounted on the circuit breaker main body 13 by fitting a plate-shaped projection 16a having a bulged tip into the same-shaped groove 1a between the phases of the main body case 1. The connection end 10a of the conductor 10 is
6 is fastened to the terminal portion 11 from the back side. The groove 1a
Uses the one provided for mounting the interphase barrier. The cover 17 is screwed from its front side to the case
Is fastened to the case 16 with screws 23 from the back side. Reference numeral 24 denotes a setting dial of the tripping operation characteristic setting unit provided on the printed board 19, and reference numeral 25 denotes a display disc associated therewith, which is printed on the disc 25 through a hole 26 of the cover 17 as shown in FIG. Set dial through hole 27 while watching the set operation value
24 is to be adjusted. On the other hand, the trip coil unit 12 is disposed in the circuit breaker main body 13 in proximity to a crossbar (not shown) of the opening / closing mechanism 8, and is connected to the printed board 18 by a lead wire 28. In such an electronic circuit breaker, when the current passing through the conductor 10 is in an overcurrent state, the trip coil unit 12
Operates, and the plunger (not shown) moves the crossbar to open / close the opening / closing mechanism 8. According to the illustrated configuration, the trip coil unit 12 is mounted in the main body 13 instead of the mechanical overcurrent trip device using the circuit breaker main body 13 shared with the mechanical circuit breaker, and a molded case is further provided on the load side. An electronic circuit breaker can be manufactured only by inserting the conductor 15 and connecting the conductor 10 to the terminal portion 14.
Therefore, it is possible to share parts and to use the same assembly line, and to use various electronic overcurrent trip devices having different functions without changing the case 1 and the cover 2 on the main body 13 side. Can be freely selected according to In addition, the electronic overcurrent trip device is sold separately,
It is also possible to enable the customer to convert the mechanical circuit breaker to an electronic one if necessary.

【The invention's effect】

According to the present invention, an electronic circuit breaker can be configured by using a circuit breaker main body that is prepared as a standard mechanical type without preparing a circuit breaker main body dedicated to an electronic type. Cost reduction is possible by using a common and shared assembly line, and not only an overcurrent trip function, but also a ground fault protection function, open-phase protection function, advance warning function, noise filter function, power demand monitoring function, etc. An electronic overcurrent trip device equipped with various functions required for maintenance and management control of a power distribution system can be freely selected using the same circuit breaker body.

[Brief description of the drawings]

FIG. 1 is a side view of a circuit breaker provided with an overcurrent trip device according to an embodiment of the present invention, in which a main part is shown in cross section, FIG. 2 is a plan view of the main part, and FIG. FIG. 4 is a perspective view of a tripping operation characteristic setting unit in the overcurrent tripping device, and FIG. 4 is a longitudinal sectional view of a circuit breaker showing a conventional example. 8 Opening / closing mechanism, 10 Conductor, 11 Current transformer, 12
Trip coil unit, 13 ... Circuit breaker body, 14 ...
... Terminal part, 15 ... Molded case.

Claims (1)

(57) [Claims] In a molded case mountable on a load side of a circuit breaker body, a conductor having one end connected to a load-side terminal of the circuit breaker body and the other end serving as a terminal flows through the conductor. A current transformer for detecting a current and an electronic circuit for monitoring a current signal of the current transformer and outputting a trip signal when the current flowing through the conductor is judged to be in an overcurrent state are housed. An overcurrent trip device for a circuit breaker, wherein a trip coil unit for receiving an output and opening and closing a switching mechanism of the circuit breaker body is disposed in the circuit breaker body.