JPH0218489Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of an electromagnetic contactor equipped with an arc extinguishing mechanism.

Generally, this type of electromagnetic contactor is used to start and stop three-phase induction motors, etc., but more recently it is used as a control device for starting and stopping motors that drive automation, labor-saving devices, etc. As its uses expand, the arc extinguishing mechanism attached thereto also frequently starts and stops the electric motor. There is a need for something that can handle so-called inching operation.

Figures 1 to 3 show this type of conventional electromagnetic contactor. In the figures, 1 is a mounting base made of steel plate;
2 is an insulating case to which the mounting base 1 is screwed; 4 is a fixed core; 5 is an operating coil attached to the fixed core 4; 6 is a leaf spring interposed between the fixed core 4 and the mounting base 1; 7 is a movable iron core, which is attracted to the fixed iron core 4 when the operating coil 5 is energized.

A cross bar 8 is made of an insulating material and is connected to the movable iron core 7 by a pin 9.

Reference numeral 10 denotes a trip spring disposed between the crossbar 8 and the mounting base 1, which pushes up the crossbar 8 so that the main circuit is always open. Reference numeral 11 denotes a movable contactor having a contact point 11a, which is inserted into a holding hole 8a provided in the crossbar 8.

12 is a pressure spring, 13 is a fixed contact with a contact 13a facing the contact 11a, and a fixing screw 14.
is fixed to the terminal plate 15 by
is fixed to the insulating case 2 with screws 16 and 17. 18 is a terminal screw connected to the main circuit electric wire, 1
9 is an arc box made of insulating material, and screw 2
0 to the insulating case 2.

The arc box 19 consists of a guide portion 19a of the cross bar 8, a ceiling portion 19b for preventing the arc and hot gas from being ejected upward, and a side plate 19c for preventing the arc and hot gas from being ejected directly to the outside.

Reference numeral 21 denotes a well-known arc extinguishing grid having a V-shaped groove 21a formed in the center thereof, and is installed in the arc box 19.

Next, the opening/closing operation of a conventional contactor will be explained.

As shown in FIG. 2, when a voltage is applied to the operating coil 5 with the main circuit open, a magnetic flux is generated between the fixed core 4 and the movable core 7, resisting the force of the tripping spring 10. The movable iron core 7 is then attracted to the fixed iron core 4. As a result, the crossbar 8 operates in the same manner, and the contact 11a of the movable contact 11 comes into contact with the contact 13a of the fixed contact 13, and
The main circuit is closed while a predetermined pressure is applied by the pressure spring 12.

On the other hand, when the operating coil 5 is demagnetized,
The force of the trip spring 10 causes the movable core 7 to separate from the fixed core 4, and the crossbar 8 also moves in conjunction with this. Therefore, the crossbar 8 returns to the state shown in FIG. 2, and the contact 11a of the movable contact 11 and the contact 13a of the fixed contact 13 are separated. During this opening, an arc is generated between the contacts 11a and 13a at a portion indicated by A in FIG.
The arc extinguishing grid 21 is driven by magnetic force in the direction of 1a.
The arc is extinguished by the increase in arc voltage due to the arc series gap between the two (due to the elongation of the arc positive column).

Since the conventional electromagnetic contactor is configured as described above, the temperature and pressure inside the arc box 19 become abnormally high due to the thermal energy of the hot gas when an arc is generated, causing damage to the arc box 19, the crossbar 8, and both sides. This causes insulation deterioration of the walls 22a, 22b, etc., and a large amount of hot gas is released to the outside.

This invention was made to eliminate such conventional drawbacks, and one embodiment of this invention will be described below.

In FIG. 4, reference numeral 23 refers to a plurality of metal plates provided with a large number of pores, as shown in FIG. As shown in FIG. 5, they are assembled in the upper gap together with the arc extinguishing grids 21, which are assembled in a predetermined number on both side walls 22a, 22b, and 19 and is of course insulated from the terminal board 15. The arc extinguishing grid 21 has a V-shaped groove 21 in the center.
When the arc is driven toward the tip of this groove, hot gas flows upward from this groove due to the arc's driving force and temperature rise, that is, to the heat absorbing plate provided at the top of the arc extinguishing grid 21. It will be emitted in the direction. Also Arkbox 19
However, the guide portion 19a of the cross bar 8, the ceiling portion 19 that prevents arc and hot gas from blowing upward
b. It is the same as the conventional one in that it consists of a side plate 19c that prevents arc and hot gas from directly ejecting to the outside.

Next, the operation of the electromagnetic contactor of the present invention will be explained.

To change the circuit from the closed state to the open state shown in FIG. When they are separated, the crossbar 8 also moves in conjunction with the movable iron core 7.

Therefore, the crossbar 8 returns to its original state as shown in FIG.
a and the contact 13a of the fixed contact 13 are separated.
Upon this opening, an arc is generated between the contacts 11a and 13a at the part shown by A in FIG. The arc is extinguished by the rise in arc voltage due to the arc series gap between the two.

In addition, in this invention, Arkbox 1
A plurality of heat absorbing plates 23 made of metal plates with a large number of pores are provided in the upper arc emitting part of the arc extinguishing grid 21 inside the arc extinguishing grid 21, using the side walls 22a and 22b so that the positions of the opposing pores do not overlap. By arranging them vertically with a predetermined gap, the hot gas of the arc generated during interruption passes through the pores of the heat absorption plate 23 on the front side, collides with the next heat absorption plate 23, and is diffused, and this state is repeated one after another. In between, the thermal energy of the hot gas is quickly absorbed by each of these heat absorbing plates 23, cooled, and released to the outside. Note that when the heat absorption plate absorbs the thermal energy of the hot gas, the temperature of the hot gas decreases, but the heat absorption plate is warmed.
However, the heat absorption plate is not insulated, and the heat stored in the heat absorption plate is transferred from the heat absorption plate 23 to the gas in the arc box to the arc box 1a to the external gas, similar to the heat stored in the arc extinguishing grid. (Air) path and heat absorption plate 23 → both side walls 22a, 2
Since the heat is released to the outside through the path 2b→terminal plate 15→external electric wire, the purpose of the heat absorbing plate can be fully achieved. Moreover, for example, if we use iron for the heat absorbing plate,
The specific heat of iron is about 3000 times that of air (per unit volume), so even if the heat absorption plate absorbs all of the increase in heat energy of the air when an arc occurs, the temperature of the heat absorbing plate will be much smaller than that of air. It can be said to have heat capacity. In the above embodiment, a plurality of heat absorbing plates 23 shown in FIG. 6 are connected to each arc extinguishing grid 21 in the upper gap by using both side walls 22a and 22b of the arc extinguishing grid 21, as shown in FIG. The heat absorbing plate 23 was assembled parallel to the arc box 19 on the side of the ceiling 19b as shown in FIG. In this case, the eighth
As shown in the figure, it is assembled together with a predetermined number of arc extinguishing grids 21 in combination between the side walls 22a and 22b so as to be perpendicular to these in the side gap, fitted into the arc box 19, and connected to the terminal plate 15. may be insulated. This means that the movable contact 11a is the fixed contact 13
Since the arc generated when opening from the arc extinguishing grid 21 is driven by magnetic force toward the tip side of the V-shaped groove 21a, the hot gas generated by this arc also moves toward the tip side of the arc extinguishing grid 21, that is, the V-shaped groove 21a. 7
This is because it is emitted from the gap between the arc extinguishing grids on the side of the figure.

In the configuration shown in FIG. 7 as well, the thermal energy of the hot gas in the arc box can be absorbed by each heat absorbing plate similarly to the configuration shown in FIG. Since the electromagnetic contactor of this invention is constructed as described above, the thermal energy of the hot gas at the time of arc generation is quickly absorbed by each heat absorbing plate, so it can be cooled quickly and the amount of hot gas released to the outside can be reduced. Not only can it be significantly reduced, but it is also very useful for extending the breaking performance and the switching life.

[Brief explanation of the drawing]

Fig. 1 is a front view of a conventional electromagnetic contactor with its right half in cross section, Fig. 2 is a right side view showing a central cross section of the electromagnetic contactor, and Fig. 3 is a perspective view of a conventional arc extinguishing grid. Fig. 4 is a sectional view corresponding to Fig. 2 showing the essential parts of an embodiment of this invention, Fig. 5 is an assembled perspective view of the arc extinguishing grid and heat absorbing plate in the invention, and Fig. 6. 7 is a perspective view of a heat absorbing plate, FIG. 7 is a sectional view corresponding to FIG. 4 showing another embodiment of this invention, and FIG.
This figure is an assembled perspective view of the arc extinguishing grid and the heat absorbing plate used in the one shown in FIG. In the figure, 19 is an arc box, 21 is an arc extinguishing grid in the arc box, 22a, 22b
23 indicates both side walls, and 23 indicates a heat absorbing plate. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims for Utility Model Registration] (1) An arc extinguishing grid provided between the discharge part of the arc extinguishing grid provided in the arc box and the arc box to prevent the hot gas emitted from the discharge part from being directly discharged to the outside. a plurality of heat absorbing plates arranged in parallel at appropriate intervals; and a large number of pores provided in each of the heat absorbing plates, the pores being arranged so as not to overlap in adjacent heat absorbing plates. An electromagnetic contactor characterized by comprising the following. (2) The utility model according to claim 1, characterized in that the plurality of heat absorbing plates are assembled in a gap above both side walls of the arc extinguishing grid so as to be parallel to the arc extinguishing grid. Magnetic contactor. (3) The utility model registration claim 1 is characterized in that the plurality of heat absorbing plates are assembled in side gaps between both side walls of the arc extinguishing grid so as to be perpendicular to the arc extinguishing grid. electromagnetic contactor.