Patent Description:
In general, a molded case circuit breaker (MCCB) is an electric instrument that is installed in part of an electric system to protect the circuit and load by automatically breaking the circuit in an electrical overload state or a short circuit fault.

The molded case circuit breaker generally includes a terminal part that may be connected to a power side or load side, a contact part including a fixed contact and a movable contact that may come in contact with or be separable from the fixed contact to connect or separate the circuit, a switching mechanism that moves the movable contact to supply power required to open/close the circuit, a trip part that detects an over-current or short circuit current at the power side to induce a trip motion of the switching mechanism, and an extinction part that extinguishes an arc occurred in cutting off an abnormal current.

Of the molded case circuit breakers, one connected to the main bus bar of the distribution board is called a plug-in molded case circuit breaker.

<FIG> and <FIG> illustrate a conventional plug-in molded case circuit breaker. <FIG> is a perspective view illustrating that the conventional molded case circuit breaker is installed in a distribution board, and <FIG> is a perspective view illustrating that external connection devices are connected to the load-side terminal of the molded case circuit breaker.

The molded case circuit breaker <NUM> is connected to a bus bar <NUM> with its power-side terminal 1a, and the load-side terminal 1b is fitted to the distribution board panel <NUM> by a mounting bracket <NUM>. In the case of a three-phase circuit, the bus bar <NUM> is arranged in a row of three. The bus bar <NUM> is mounted side by side on the side of the distribution board panel <NUM> by a bus bar mounting bracket 2a formed from an insulating material.

The power-side terminal 1a of the molded case circuit breaker <NUM> is equipped with a connector (not shown) and a finger assembly (not shown) to connect the bus bar <NUM> to the fixed contactor (not shown). This allows the current to flow from the bus bar <NUM> to the finger assembly, through the connector and into the interior (fixed terminal) of the molded case circuit breaker <NUM>. The conductive state, i.e. when the handle <NUM> is rotated to the On-position, the movable contact (not shown) inside the molded case circuit breaker <NUM> is connected to the fixed contact (not shown) so that the circuit is energized.

The power-side terminal 1a is equipped with a base bus supporter <NUM> formed of an insulating material to protect internal components from arcs and gases of high temperature emitted from the inside of the breaker during short circuit break and to secure insulation between conductors or from the outside. The base bus supporter <NUM> functions for maintaining and protecting insulation around the power-side terminal 1a.

The load-side terminal 1b of the molded case circuit breaker <NUM> may be connected to an external connection device <NUM> such as a power meter, as shown in <FIG>. At this time, the connecting bus bar <NUM> of the external connection device <NUM> is connected to the load-side terminal (not shown) inside the load side terminal1b and the molded case circuit breaker <NUM> and the external connection device <NUM> are electrically connected to each other.

However, there may be a gap between the molded case circuit breaker <NUM> and the external connection device <NUM> for compatibility or to prevent interference, depending on the product. In this case, the connecting bus bar <NUM> is placed in the space between the load-side terminal 1b and the external connection device <NUM> of the molded case circuit breaker <NUM> in an exposed state. Due to this, there is a possibility of insulation breakdown.

<CIT> discloses a low-voltage switching device. The device is provided with a protection unit to prevent contact with the live electric parts or wires arranged between the load and the power unit.

<CIT> discloses a circuit interrupter including separable main contacts, an operating mechanism interconnected with the contacts, and a housing in which the contacts and the operating mechanism are disposed. The housing includes a first attaching region and a mounting cutout. A shield is provided that includes a second attaching region attaching with the first attaching region for connecting the shield to the housing. The shield includes a tab adapted for covering the mounting cutout when the connection is made.

<CIT> discloses a terminal cover of a low-voltage circuit breaker. The terminal cover is provided with a pair of side plates and a flat coupling plate. The terminal cover is further provided with, as a coupling means, a projection and a recess on the pair of side plate.

Therefore, an aspect of the detailed description is to provide a molded case circuit breaker that prevents the possibility of insullation faillure occurring at the load-side terminal.

To achieve these and other advantages and in accordance with the purpose of this specification, as embodied and broadly described herein, a molded case circuit breaker having a load-side terminal connected to an external connection device includes: an insulating cover coupled to an enclosure of the molded case circuit breaker, in which the insulating cover includes an insulating wall interposed between the enclosure and the external connection device.

Here, the insulating cover is equipped with side walls covering the side of the load-side terminal.

In addition, the insulation wall includes a partition wall that is formed at an inner portion of the insulating wall to protrude and inserted into a recess formed on an inter-phase partition wall of the load-side terminal.

In addition, the partition wall includes a protrusion that is formed an end portion of the partition wall and coupled by fitting to a fixing part formed at an end of the inter-phase partition wall.

In addition, the insulating partition wall includes an opening through which a terminal of the load-side terminal is exposed.

In addition, an insertion part is formed on a contact portion between the insulating wall and the partition wall, through which a coupling part formed to protrude on a front face of the external connection device is inserted.

In addition, a monitoring hole is formed on the upper face of the insulating cover to identify the internal condition of the load-side terminal.

In addition, a cover opening is formed on the upper part of the enclosure so that the upper cover provided at the upper part of the enclosure can be exposed.

In addition, a protruding front cover covering the upper support of the base bus supporter that is fitted to the front of the enclosure is formed on the front of the insulating cover.

According to the molded case circuit breaker in accordance with one embodiment of the present disclosure, any exposure space does not exist even when external connection devices are connected to the load-side terminal, preventing insulation damage by the connecting bus bars etc..

Independent claim <NUM> defines the invention in an aspect. Dependent claims <NUM> to <NUM> state various embodiments according to the invention in that aspect.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings, so that a person skilled in the art can easily carry out the invention.

Referring to the accompanying drawings, description will be given in detail of a molded case circuit breaker in accordance with each embodiment of the present disclosure.

The molded case circuit breaker having a load-side terminal <NUM> connected with an external connection device <NUM> in accordance with one embodiment of the present disclosure includes an insulating cover <NUM> coupled to an enclosure <NUM> of the molded case circuit breaker, and the insulating cover <NUM> includes an insulating wall <NUM> interposed between the enclosure <NUM> and the external connection device <NUM>.

The enclosure <NUM> of the molded case circuit breaker is constructed approximately into a boxed shape of a cube. The top of the enclosure <NUM> is equipped with a handle <NUM> to operate the switching mechanism. The handle <NUM> may be rotated to the On-position, the Off-position, and the Reset-position.

The front part of the enclosure <NUM> is provided with a power-side terminal <NUM> that may be connected to the power line, and the rear (right side of the drawing) is provided with a load-side terminal <NUM> that may be connected to the load. The upper surface of the power-side terminal <NUM> and the upper surface of the load-side terminal <NUM> form an assembly hole <NUM> so that the load may be assembled and monitored on the terminal side, respectively.

A contact part is provided inside the enclosure <NUM>. The contact part is provided with a fixed contact (not shown) and a movable contact (not shown) that may be contacted or separated by the action of the switching device including the handle <NUM> to connect or disconnect the circuit.

Multiple bus bars <NUM> are installed on a panel (not shown) of a distribution board. For three-phase circuits, the bus bars <NUM> may be installed in parallel. The main current flowing through the bus bars <NUM> will flow in the load through the molded case circuit breaker.

The load-side terminal <NUM> of the enclosure <NUM> is secured to the panel of the distribution board by a mounting bracket <NUM>.

The load-side terminal <NUM> is provided with an inter-phase partition wall <NUM>. The inter-phase partition wall <NUM> is provided with a recess along the direction of height at the end. The inner part of the recess <NUM> is provided with a fixing part <NUM>. The insulating cover <NUM> is inserted into the recess <NUM> and the fixing part <NUM> and secured therebetween.

The upper part of the enclosure <NUM> is provided with an upper cover <NUM>. In some cases, the enclosure <NUM> is referred to as a case, and the case and cover are collectively referred to as the enclosure.

The power-side terminal <NUM> is provided with a connection member for connecting the power-side terminal (which may be integrated with the fixed contacts) extended from the fixed contact (not shown) to the bus bar <NUM>. The connection member may consist of connectors (not shown) and finger assemblies (not shown).

As shown above, the molded case circuit breakers that may be connected to the bus bar are also called a plug-in molded case circuit breaker.

A base bus supporter <NUM> is provided to protect the connection member between the power-side terminal <NUM> and the bus bar <NUM> and maintain insulation with the outside. The base bus supporter <NUM> is formed of an insulating material.

The base bus supporter <NUM> is fixed to the power-side terminal <NUM> so as to cover the connecting member. The base bus supporter <NUM> may be formed in the form of a box which is open at the rear as a whole.

An entry part <NUM> is provided at the front of the base bus supporter <NUM>. The entry part <NUM> may be formed in the form of multiple teeth from the side to allow fit between the bus bar <NUM>. These teeth may be formed to be engaged in the bus bar <NUM>.

An upper support <NUM> is provided on the upper part of the base bus supporter <NUM>. The upper support <NUM> has an accommodation space, and an inter-phase partition wall is provided in the accommodation space.

A mounting bracket <NUM> is provided. The mounting bracket <NUM> is installed on the distribution board panel and secures the enclosure <NUM> of the molded case circuit breaker and the external connection device <NUM>.

The external connection device <NUM> is installed at the load-side terminal <NUM>. The external connection device <NUM> may be a power meter that measures the amount of power.

A device terminal <NUM> of the external connection device <NUM> is exposed to the connecting bus bar <NUM> for each phase. The connecting bus bar <NUM> may be connected to a terminal <NUM> of the load-side terminal <NUM>.

A coupling part <NUM> protrudes between each phase of the device terminal <NUM> of the external connection device <NUM>. An insulating cover <NUM> is fitted to the coupling part <NUM>.

The insulating cover <NUM> is provided to prevent insulation failure of the connecting bus bar <NUM>, which is exposed to the space between the molded case circuit breaker and the external connection device <NUM>. The insulating cover <NUM> is fitted to the enclosure <NUM> of the molded case circuit breaker. The insulating cover <NUM> is fitted in a downward direction from the top of the enclosure <NUM>.

The insulating cover <NUM> is provided with a cover opening <NUM> so that the top cover <NUM> of the molded case circuit breaker may be exposed. The user can operate the handle <NUM> through the cover opening <NUM>.

The top face of the insulating cover <NUM> is constructed with a monitoring hole <NUM> to provide access to the assembly hole <NUM>. The monitoring hole <NUM> is formed on the front and rear sides respectively to connect to the assembly hole <NUM> on the power-side terminal <NUM> and the assembly hole <NUM> on the load-side terminal <NUM>. Users can visually determine the assembly status of the terminal through the monitoring hole <NUM> and the assembly hole <NUM>. In addition, the user can check the temperature status of the terminal through the monitoring hole <NUM> and the assembly hole <NUM> using equipment such as a thermometer or a thermal infrared camera.

The insulating cover <NUM> is provided with sidewall <NUM> on the side of the rear. The sidewall <NUM> covers the side 13a of the load-side terminal <NUM>. It is desirable that the sidewall <NUM> is formed in such a size that it covers the side 13a of the load-side terminal <NUM>. In other words, it is desirable for the sidewall <NUM> to form more than the width and height of the load-side terminal. As a result, insulation is improved.

The sidewall <NUM> has a specified gap from the side 13a of the load-side terminal <NUM> (see <FIG> and <FIG>). Accordingly, an outlet passage (E) is provided for the leakage of gas or foreign substances from the arc or electric spark that occurs at the load-side terminal <NUM> or the connecting bus bar <NUM>.

The insulating wall <NUM> is provided at the rear of the insulating cover <NUM>. The insulating wall <NUM> is disposed between the enclosure <NUM> and the external connection device <NUM> to improve insulation.

A gap (C) of a certain distance occurs between the load-side terminal <NUM> and the insulating wall <NUM> (see <FIG> and <FIG>). This gap serves as a gas outlet and also maintains the distance between the molded case circuit breaker and the external connection device <NUM>.

The insulating wall <NUM> has a protruding partition wall <NUM> that is inserted into a recess <NUM> of an inter-phase partition wall <NUM> of the load-side terminal <NUM>. The partition wall <NUM> is prepared and extended to the inter-phase partition wall <NUM> of the load-side terminal <NUM>. Accordingly, the connecting bus bar <NUM> of the external connection device <NUM> is closed to the space surrounded by the partition wall <NUM> and the insulating wall <NUM> for each phase.

At the end of the partition wall <NUM>, a protrusion <NUM> is formed, which is fitted into the fixing part <NUM> of the inter-phase partition wall <NUM>. The protrusion <NUM> may be formed in the form of a circular or polygon. The protrusion <NUM> is formed thicker than the thickness of the partition wall <NUM>. The insulating cover <NUM> may only be fitted or removed in the upper and lower directions, without detaching forward or backward by means of the protrusion <NUM>.

On the insulating wall <NUM>, a terminal opening <NUM> is formed so that the terminal <NUM> of the load-side terminal <NUM> may be exposed. The terminal opening <NUM> is prepared for each phase. The terminal opening <NUM> may be formed by grooves that has a certain width and height from the bottom of the insulating wall <NUM>.

Where the insulating wall <NUM> and the partition wall <NUM> are in contact, an insertion part <NUM> is formed that allows the coupling part <NUM> protruding to the front of the external connection device <NUM> to be inserted. The coupling part <NUM> of the external connection device <NUM> and the insertion part <NUM> of the insulating cover <NUM> are inserted and the insulating cover <NUM> is also fixed with the external connection device <NUM>.

The front of the insulating cover <NUM> protrudes a front cover <NUM> covering the upper support <NUM> of the base bus supporter <NUM> which is fitted to the front of the enclosure <NUM>. The front cover <NUM> may be of the shape and size covered by the coupling of a part of the upper support <NUM> of the base bus supporter <NUM>.

The insulating cover <NUM> is constructed from the upper support of the base bus supporter <NUM> equipped on the front of the molded case circuit breaker to the external connection device <NUM> located on the rear of the molded case circuit breaker, and installed stably, preventing the connecting bus bar <NUM> of the external connection device <NUM> from being exposed to damage to insulation.

The insulating cover <NUM> includes sidewalls <NUM>, which refer to the side 13a of the load-side terminal of the molded case circuit breaker, which improves insulation performance.

The insulating cover <NUM> creates a gap (E,C) between the side 13a and the rear of the load-side terminal <NUM>, thus inducing the discharge of arc gas or debris.

<FIG> is a perspective view of an insulating cover applied to a molded case circuit breaker in accordance with another embodiment of the present disclosure.

For this insulating cover 40A, the same reference number is used for the same part as the previous embodiments.

Claim 1:
A molded case circuit breaker having a load-side terminal (<NUM>) for being connected to an external connection device (<NUM>), comprising:
an insulating cover (<NUM>) coupled to an enclosure (<NUM>) of the molded case circuit breaker, in which the insulating cover (<NUM>) includes an insulating wall (<NUM>) for being interposed between the enclosure (<NUM>) and the external connection device (<NUM>),
wherein a gap (C) occurs between the load-side terminal (<NUM>) and the insulating wall (<NUM>), characterized by it additionally comprises an insertion part (<NUM>) is formed where the insulating wall (<NUM>) and a partition wall (<NUM>) of the insulating wall (<NUM>) are in contact,
wherein the insertion part (<NUM>) is configured to receive a coupling part (<NUM>) protruding to the front of the external connection device (<NUM>).