JPS6244370B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a thermal relay with open phase protection.

A conventional thermal relay of this type was constructed as shown in FIG. Bimetal 1
The first cards 2 each abut only on the low-expansion side surfaces of the
and a second card 3 that comes into contact with the high-expansion side surface of the bimetal 1 are provided in parallel, and an actuation lever 5 is arranged at the ends of both cards 2 and 3 so as to be orthogonal to both cards 2 and 3. Shaft 1 provided at one end of 5
0, the end of the first card 2 is brought into contact with a shaft 9' provided in front of one end of the actuating lever 5, and the free end of the other end of the actuating lever 5 is An operating section 8' was provided, and the operating section 8' was placed opposite the switch lever 6. In such a conventional example, when electricity is applied, the high expansion side of the bimetal 1 expands and the bimetal 1 deforms to the low expansion side.
Due to this deformation of the bimetal 1, the actuating convex portion 18 of the first card 2 is pushed, and the first card 2 is moved to the actuating lever 5.
At the same time, the second card 3 also moves to the operating lever 5 side (at this time, only the first card 2 is pushed by the bimetal 1, but the operating protrusion 18 of the second card 3 and the bimetal 1 Since a gap is created between the first card 2 and the second card 3, the second card 3 also moves in the same direction as if being pulled by the first card 2.
When the card moves toward the actuating lever 5 side, the actuating part 8' hits the switch lever 6, and the actuating lever 5 rotates about the shaft 9' and is pulled until the actuating protrusion 18 of the second card 3 comes into contact with the bimetal 1. the first card 2 and the second card 3 substantially move together in the same direction. ). If an overcurrent flows in this energized state,
The bimetal 1 is further deformed toward the operating lever 5 side, the first card 2 and the second card 3 are further moved, and the switch lever 6 is pushed a certain amount by the operating section 8', thereby operating the switch section. In addition, when an open phase occurs in the energized state, the first card 2 moves toward the actuating lever 5 side with the bimetal 1 deformed toward the actuating lever 5, but the bimetal 1, which is not deformed due to the open phase, moves to the second The card 3 does not move toward the actuating lever 5, the first card 2 and the second card 3 move in relatively opposite directions, and the actuating lever 5 rotates around the shaft 10 so that the operating part 8' The switch part is operated by pushing the switch lever 6 a certain amount. By the way, in this type of thermal relay, in order to freely change the operating set current, the angle of the switch lever 6 at which the switch section operates can be adjusted by adjusting the position of the pivot shaft of the switch lever. In other words, when the set current is large, the switch section will not operate unless both cards 2 and 3 move a large amount, and when the set current is small, the switch section will operate even if the amount of movement of both cards 2 and 3 is small. I'm starting to do that. However, in the above conventional example, the same operating section 8' operates the switch section by pushing a fixed position a fixed distance from the pivot shaft of the switch lever 6, both in the event of an overcurrent and in the event of a phase loss. Operation margin for pressing the switch lever 6 to operate the switch part (from the normal energized state to the switch lever 6
The interval at which the switch is activated by pressing is the same regardless of the set current. When the phase is open, the difference in the amount of movement of both cards 2 and 3 is amplified by the action of the lever and is transmitted to the operating section 8'. Therefore, when the set current is large, the difference in deflection of the bimetal 1 due to variations in components among the three phases and unbalanced current becomes large, resulting in a disadvantage that mistrips are likely to occur even though there is no open phase. Also, if you prevent mistrips when a phase is missing when the set current is large, the difference in the amount of movement of both cards 2 and 3 during a phase open when the set current is small is small, so there is a drawback that the ability to detect a phase open will be low. .

The present invention has been made in view of the above points, and an object of the present invention is to prevent mistrips caused by unbalanced current, and to make the open-phase protection characteristics uniform over the entire set current width. It is possible to provide thermal relays.

The present invention will be explained in detail below with reference to Examples. 1 is U.
It is a bimetal provided corresponding to each phase of VW, and both ends are connected to power supply side and load side terminals 14 and 1, respectively.
A heater 16 connected to the bimetallic metal 1
bends and deforms. 17 is a terminal screw. Reference numeral 2 denotes a first card, and the first card 2 has an actuating convex portion 18 protruding from a side end portion of the first card 2 so as to come into contact with a low-expansion side surface at the lower part of the bimetal 1. 3
is a second card, and the second card 3 has an actuating convex portion 18 protruding from its side end portion, which abuts against the high-expansion side surface of the bimetal 1 at the lower portion thereof. The first card 2 and the second card 3 are arranged in parallel within the same plane. Also, 5 is the first,
It is an actuating lever that is hung horizontally at the ends of the second cards 2, 3 at right angles to both cards 2, 3, and as shown in FIG. It has been set up. The end of the second card 3 is pivoted to a shaft 10, and the end of the first card 2 is pivoted to a shaft 9, thereby linking the first card 2 and the operating lever 5. At the end of the first card 2, a first actuating part 7 for pressing the switch lever 6 of the switch part 4 is protruded, and also for pressing the switch lever 6 at the lower part of the other free end of the actuating lever 5. A second operating section 8 is provided. Such first operating section 7
The positions where the second operating portion 8 contacts the switch lever 6 are l ₁ and l ₂ from the pivot shaft 6a of the switch lever 6.
(l ₁ < l ₂ ). In other words, from the position where the first operating section 7 contacts the switch lever 6, the second operating section 8
The position where it contacts the switch lever 6 is on one end side of the switch lever 6 (lower side of the drawing in Fig. 3).
It is becoming. The switch lever 6, which is supported by the pivot shaft 6a, is rotated clockwise in the figure by the first operating section 7 and the second operating section 8, and the movable contact plate 4
The reversing spring 23 attached to the switch lever 6 is pushed and driven by the other end side of the switch lever 6, and the COM contact 21 attached to the movable contact plate 40 is moved to the NO contact 24 and
A switch portion 4 is constructed by attaching the contact to the NC contact 25 so that the contact can be exchanged freely. 26 is an NC terminal, 27 is a current value switching lever, 28 is a return button, 29 is a return button support spring, 30 is an NO terminal, 31 is a tester card, 35 is a COM terminal, 37 is a cover, and 38 is a case. 33 is a dial interlocking metal fitting,
The lower end of the dial interlocking fitting 33 is rotatably supported by a pivot shaft 33a. Reference numeral 36 denotes a current value adjustment dial, and by rotating the current value adjustment dial 36, the dial interlocking fitting 33 is rotated around the pivot shaft 33a by an eccentric cam 36a, and is integrated with the dial interlocking fitting 33. The angle of the switch lever 6 can be changed by changing the position of the provided pivot shaft 6a. Reference numeral 32 denotes an interlocking metal fitting support spring, which biases the end of the dial interlocking metal fitting 33 opposite to the pivot shaft 33a so as to press it against the eccentric cam 36a. 34 is the adjustment screw and dial adjustment fitting 3
3, the position of the pivot shaft 6a can be finely adjusted.

Next, the operation of the thermal relay configured as described above will be explained. When energized, the high expansion side of the bimetal 1 expands and the bimetal 1 is deformed to the low expansion side, but this deformation of the bimetal 1 pushes the actuating convex portion 18 of the first card 2, causing the first card 2 to move into the actuating lever. Move to the 5 side and add the second card 3 along with this.
(At this time, only the first card 2 is pushed by the bimetal 1, but since there is a gap between the actuating protrusion 18 of the second card 3 and the bimetal 1, the first card 2 is pushed by the bimetal 1.) As if being pulled, the second card 3 also moves in the same direction). When this energization state is a normal current, the first actuating part 7 and the second actuating part 8 just come close to the switch lever 6 and do not push the switch lever 6 to actuate the switch part 4. When an overcurrent flows in the energized state, the bimetal 1 further deforms toward the actuating lever 5 side, and the actuating lever 5 remains perpendicular to the first card 2 and the second card 3 while the first card 2 and the second card 3 2 card 3 further moves to the left in FIG.
presses the switch lever 6 by a certain amount, the movable contact plate 40 is reversed, and the switch portion 4 is operated. In addition, when an open phase occurs in the energized state, the first card 2 moves toward the actuating lever 5 side with the bimetal 1 deformed toward the actuating lever 5, but the bimetal 1, which is not deformed due to the open phase, moves to the second Card 3 is actuating lever 5
The first card 2 and the second card 3 move in opposite directions, and the operating lever 5 rotates around the shaft 10 so that the second operating part 8 holds the switch lever 6 at a constant position. When pressed, the movable contact plate 40 is reversed and the switch portion 4 is operated. Furthermore, the distance l1 from the pivot shaft 6a to the position where the first operating part 7 contacts the switch lever ₆ , and the distance _l2 from the pivot shaft 6a to the position where the second operating part 8 contacts the switch lever 6 are l. ₁ <
l ₂ , the operating margin d of the second operating section 8 when the set current is small as shown in FIG. 6a is greater than the operating margin d when the set current is large as shown in FIG. 6b. d′ becomes larger. In other words, the set current is adjusted by rotating the dial interlocking fitting 33 using the current value adjustment dial 36, moving the pivot shaft 6a of the switch lever 6, and changing the angle at which the switch part 4 is operated by the switch lever 6. However, when the set current is small, the tilt angle at which the switch lever 6 operates is small with respect to the vertical direction, as shown in Figure 6a, and when the set current is large, as shown in Figure 6b, the angle of inclination at which the switch lever 6 operates is small. On the other hand, if the inclination angle at which the switch lever 6 operates increases and the relationship l ₁ < l ₂ is established, the second
The operating margin between the operating section 8 and the switch lever 6 increases as the set current increases. Therefore, when the set current is large, even if there are variations in the amount of deflection between the bimetals 1 of each phase, the switch lever 6 will not be pressed and cause a mistrip, and when the set current is small, the switch will operate reliably even if a phase is missing.

FIG. 7 shows another embodiment of the description. In this embodiment, the first operating portion 7 is connected to the operating lever 5.
The first card 2 and the operating lever 5 are connected by engaging the end of the first card 2 opposite to the switch lever 6 side of the first operating section 7. This embodiment also operates in the same manner as the previous embodiment.

As described above, when the first and second cards move in the same direction during an overcurrent, the first actuating part that presses the switch lever of the switch part is placed near the connecting part between the actuating lever and the end of the first card. A second actuating part is provided at the other free end of the actuating lever to press the switch lever of the switch part when the first card and the second card move in relatively opposite directions in the event of a phase failure. The length from the pivot shaft of the switch lever to the position where the second operating part contacts the switch lever is longer than the length from the pivot shaft of the switch lever in the section to the position where the first operating part contacts the switch lever. The first operating part and the second
Since the height positions of the operating parts are different, in the event of an overcurrent, the first operating part pushes the switch lever a certain amount to operate the switch, and in the event of a phase failure, the second operating part moves the switch lever at a constant level by rotating the operating lever. Of course, the switch part operates when the switch lever is pressed, providing overcurrent protection and open phase protection. When the current is large, mistrips due to component variations and current imbalance do not occur, and even when the set current is small, it operates reliably in the event of an open phase. Therefore, variations in trip characteristics caused by component variations and current imbalance are improved, and open-phase protection characteristics are made uniform.

[Brief explanation of the drawing]

1 is a plan view of an embodiment of the present invention, FIG. 2 is a front view of FIG. 1, FIG. 3 is a front sectional view of FIG. 2, FIG. 4 is a plan sectional view of FIG. Figure 5 is an exploded perspective view showing the operating lever and the first and second cards, Figures 6a and b are schematic perspective views for explaining the operation of the same, and Figure 7 is a flat view of another embodiment of the same. Sectional view, No. 8
The figure is a plan sectional view of a conventional example, in which 1 is a bimetal, 2 is a first card, 3 is a second card, 4 is a switch section, 5 is an operating lever, 6 is a switch lever,
7 is a first operating section, and 8 is a second operating section.

Claims (1)

[Claims] 1. A first card that abuts only the low-expansion side surfaces of the bimetal of each of the three phases, and a second card that abuts only the high-expansion side surfaces of the bimetal, respectively, are provided approximately parallel to each other, and the switch section is activated by displacement of both cards. In a thermal relay that operates, an operating lever is horizontally mounted on the end sides of both cards in a direction perpendicular to both cards, and the end of the second card is pivoted to one end of the operating lever, and the end of the first card is attached to the end of the first card. The end of the first card is linked to one end of the operating lever in front of one end of the operating lever so that the operating lever is pushed when the first card moves toward the operating lever, and when both cards move in the same direction during an overcurrent, the switch section A first operating part for pressing the switch lever is provided near the connecting part between the operating lever and the end of the first card, and when the first card and the second card move in relatively opposite directions during a phase failure. A second operating part that presses the switch lever of the switch part is provided at the other free end of the operating lever, and the length from the pivot shaft of the switch lever of the switch part to the position where the first operating part contacts the switch lever is provided. Sayori,
The height position of the first operating part and the second operating part are different so that the length from the pivot shaft of the switch lever to the position where the second operating part contacts the switch lever is longer. thermal relay.