Contactor

Abstract

The utility model discloses a contactor, which comprises a shell, a coil assembly and a static iron core, the coil assembly and the static iron core are arranged in an inner cavity of the shell, the coil assembly comprises a coil framework and a coil, and a temperature sensing element is arranged on the side wall of the inner cavity of the shell. The temperature sensing element is arranged at the position close to the static iron core and can detect the temperature of the static iron core according to heat radiated by the static iron core, the temperature sensing element is connected with the coil in series, and the temperature sensing element can cut off power supply of the coil when the detected temperature exceeds a threshold value. The contactor provided by the utility model can cut off the power supply of the coil when the working temperature of the static iron core exceeds a threshold value, and can prevent the problems of failure and breakdown of the heat-resistant enameled leather of the coil and burnout of the coil framework caused by overheating.

Description

Technical Field

[0001] The utility model relates to a contactor. Background Art

[0002] Contactors are usually composed of an electromagnetic system, a contact system, an arc extinguishing system, an actuating mechanism, an insulating shell, etc. Among them, the electromagnetic system, as an important component, usually includes a coil, a moving iron core, and a static iron core. When the coil is energized, it can generate electromagnetic attraction to drive the contacts to close or open.

[0003] During the use of existing contactors, the following abnormal conditions may occur: (1) the coil voltage is too low and the product cannot be normally attracted; (2) the coil voltage is too high and a large current is generated in the coil; (3) the action mechanism is blocked by foreign objects and cannot be normally attracted;

[0004] All of the above abnormal conditions will cause the contactor's coil and electromagnet to heat up severely, resulting in failure and breakdown of the contactor's coil heat-resistant paint and melting of the coil frame, posing a certain fire hazard.

[0005] At present, there are technologies in the prior art to prevent local overheating of contactors. For example, a contactor disclosed in a Chinese invention patent application (CN113871259A) records a technology that detects the temperature of a static contact through a temperature sensing element and controls the coil current to disconnect when the detected temperature exceeds a preset value. However, the main object of protection of this patent technology is the main circuit of the contactor. Even if the working current of the main circuit of the contactor does not exceed the load, the control circuit part of the contactor may still be damaged due to the above reasons. Summary of the invention

[0006] The utility model provides a contactor which can cut off the power supply of the coil when the temperature of the static iron core is too high, thereby preventing the heat-resistant paint coating of the coil from failing and breaking down and the coil skeleton from burning due to overheating, and has better safety performance.

[0007] The contactor of the utility model comprises a shell, a coil assembly arranged in an inner cavity of the shell, and a static iron core. The coil assembly comprises a coil frame and a coil. The coil is wound on the coil frame. The coil frame and the static iron core are cooperatively connected. A temperature sensing element is arranged on the side wall of the inner cavity of the shell. The temperature sensing element is arranged at a position close to the static iron core and can detect the temperature of the static iron core according to the heat radiated by the static iron core. The temperature sensing element and the coil are connected in series. The temperature sensing element can cut off the power supply of the coil when the detected temperature exceeds a threshold value.

[0008] Furthermore, the static iron core includes a plurality of stacked silicon steel sheets and a short-circuit ring arranged on the silicon steel sheets. The temperature sensing element is arranged at a position close to the short-circuit ring. When the coil is energized, the heat generated at the short-circuit ring is greater than that at other parts of the static iron core. Therefore, arranging the temperature sensing element at a position close to the short-circuit ring can improve the temperature detection effect.

[0009] Furthermore, the distance between the temperature sensing element and the static iron core is 5 mm-20 mm, which can improve the heat transfer effect and thus improve the temperature detection effect.

[0010] Furthermore, two wiring lugs are provided on the shell, and the two poles of the temperature sensing element are correspondingly connected to the two wiring lugs through leads arranged along the side walls of the inner cavity of the shell. The two poles of the temperature sensing element are connected in series with the coil and the coil power supply circuit through the wiring lugs. The leads and the wiring lugs can be connected by welding or plugging. The structure is simple and less space is occupied inside the shell.

[0011] Furthermore, the temperature sensing element is a self-restoring element or a disposable element. The self-restoring element refers to an element that can automatically restore the power supply of the coil after the temperature of the static iron core drops, such as a temperature-controlled switch. The disposable element refers to an element that cannot automatically restore the power supply after the temperature of the static iron core drops and needs to be replaced with a new temperature sensing element to work normally, such as a thermal fuse.

[0012] Furthermore, the temperature sensing element is located above the static iron core when the contactor is in use, which can improve the heat transfer effect.

[0013] The beneficial effects of the utility model are as follows: in the utility model, the temperature of the static iron core is detected by a temperature sensing element, and the power supply to the coil can be cut off when the temperature of the static iron core is too high, thereby preventing the coil current from being too large due to problems such as too high or too low coil voltage and foreign matter being stuck, resulting in excessive temperatures of the coil, the moving iron core and the static iron core. The heat-resistant paint of the coil can be prevented from failing and breaking down due to excessive temperature, and the coil skeleton can be prevented from melting due to excessive temperature, thereby improving the reliability and safety of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the internal structure of an embodiment of the utility model from a top view;

[0015] Figure 2 This is a schematic diagram of the internal structure of an embodiment of the utility model from a side view;

[0016] In the figure: 1, shell; 10, inner cavity; 2, coil assembly; 21, coil frame; 22, coil; 3, static iron core; 31, silicon steel sheet; 32, short-circuit ring; 4, moving iron core; 5, temperature sensing element; 61, terminal block; 62, lead wire. DETAILED DESCRIPTION

[0017] The embodiment of the contactor of the utility model is as follows Figure 1-2 As shown, it includes a shell 1, a coil assembly 2 arranged in the inner cavity 10 of the shell 1, a static iron core 3, and a moving iron core 4. The coil assembly 2 includes a coil skeleton 21 and a coil 22. The static iron core 3 includes a plurality of stacked silicon steel sheets 31 and a short-circuit ring 32 arranged on the silicon steel sheets 31. The coil 22 is wound on the coil skeleton 21. The coil skeleton 21 and the static iron core 3 are cooperatively connected. A temperature sensing element 5 is arranged on the side wall of the inner cavity 10 of the shell 1. The temperature sensing element 5 is arranged at a position close to the silicon steel sheet 31 of the static iron core 3 and can detect the temperature of the static iron core 3 according to the heat radiated by the static iron core 3. The temperature sensing element 5 and the coil 22 are connected in series. The temperature sensing element 5 can cut off the power supply of the coil 22 when the detected temperature exceeds a threshold value. After the coil 22 is powered off, the coil 22 and the static iron core 3 will stop heating.

[0018] The temperature sensing element 5 is arranged close to the short-circuit ring 32. When the contactor is abnormal, the temperature at the short-circuit ring 32 is higher than other parts of the static iron core 3. Therefore, arranging the temperature sensing element 5 close to the short-circuit ring 32 can improve the temperature detection effect.

[0019] The distance between the temperature sensing element 5 and the silicon steel sheet 31 is preferably 5 mm to 20 mm, which can improve the heat transfer effect and further improve the temperature detection effect.

[0020] The threshold value is higher than the temperature of the static iron core 3 when the contactor is working normally, and is lower than the heat resistance grade temperature of the enameled wire of the coil 22 and the thermal deformation temperature of the coil frame 21, so that the power supply of the coil 22 will not be cut off when the static iron core 3 is at the normal working temperature, and the power supply of the coil 22 can be cut off in time before the static iron core 3 reaches the temperature that causes the coil frame 21 to melt and be damaged, and before the temperature of the coil 22 reaches the temperature that causes the enameled wire to fail and be damaged.

[0021] Preferably, the threshold value=(the minimum value among the normal working temperature of the static iron core 3 + the heat resistance grade temperature of the enameled wire and the thermal deformation temperature of the coil skeleton 21) / 2.

[0022] The shell 1 is provided with two connecting pieces 61, and the two poles of the temperature sensing element 5 are correspondingly connected to the two connecting pieces 61 through the lead wires 62 arranged along the inner cavity side wall of the shell 1. The two poles of the temperature sensing element 5 are connected in series with the coil 22 and the coil power supply circuit through the connecting piece 61. The lead wire 62 and the connecting piece 61 can be connected by welding or plugging, and the structure is simple, and less space is occupied inside the shell.

[0023] The temperature sensing element 5 can be a self-restoring element that can automatically restore the power supply of the coil 22 after the temperature of the static iron core 3 drops, for example, it can be a temperature-controlled switch, or it can be a disposable element that cannot automatically restore the power supply after the temperature of the static iron core 3 drops and needs to be replaced with a new temperature sensing element 5 to work normally, for example, it can be a thermal fuse.

[0024] exist Figure 2 In the state shown in , the temperature sensing element 5 is located on the left side of the static iron core 3. The contactor will be placed horizontally in actual use so that the temperature sensing element 5 is above the static iron core 3. Since the inner cavity 10 of the shell 1 is a closed space, when the coil 22, the static iron core 3, the moving iron core 4 and other components heat up, the heat in the inner cavity 10 will continue to accumulate, and the hot air flow will show an upward trend in the closed space. The temperature at the short-circuit ring 32 is higher than that of other parts of the static iron core 3. Therefore, the temperature sensing element 5 is fixed above the short-circuit ring 32, and the abnormal temperature change in the inner cavity 10 can be detected first. The power supply of the coil 22 is disconnected before the heat resistance grade temperature of the enameled wire of the coil 22 and the thermal deformation temperature of the coil skeleton 21 are reached, which can prevent the coil 22 and the coil skeleton 21 from being damaged due to excessive temperature.

[0025] When the environmental abnormality is eliminated, the temperature sensing element 5 can be cooled down and recovered by itself or a new temperature sensing element 5 can be replaced to enable the contactor to continue to work normally.

[0026] The above embodiment is only one of the preferred specific embodiments of the present invention. Common changes and substitutions made by those skilled in the art within the technical solution of the present invention are all included in the protection scope of the present invention.

Claims

1. A contactor, comprising a housing, a coil assembly disposed in an inner cavity of the housing, and a static iron core, wherein the coil assembly comprises a coil frame and a coil, characterized in that: A temperature sensing element is arranged on the side wall of the inner cavity of the shell. The temperature sensing element is arranged at a position close to the static iron core and can detect the temperature of the static iron core according to the heat radiated by the static iron core. The temperature sensing element and the coil are connected in series. The temperature sensing element can cut off the power supply of the coil when the detected temperature exceeds a threshold.

2. The contactor according to claim 1, characterized in that: The static iron core comprises a plurality of stacked silicon steel sheets, a short-circuit ring arranged on the silicon steel sheets, and a temperature sensing element is arranged at a position close to the short-circuit ring.

3. The contactor according to claim 1 or 2, characterized in that: The distance between the temperature sensing element and the static iron core is 5mm-20mm.

4. The contactor according to claim 1, characterized in that: The shell is provided with two connecting pieces, and the two poles of the temperature sensing element are connected to the two connecting pieces correspondingly through leads arranged along the side wall of the inner cavity of the shell. The leads and the connecting pieces can be connected by welding or plugging.

5. The contactor according to claim 1, characterized in that: The temperature sensing element is a self-recovering element or a disposable element.

6. The contactor according to claim 1, characterized in that: The temperature sensing element is located above the static iron core when the contactor is in use.

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