TW202116921A - Arc bix material of direct-current low-voltage circuit breaker being suitable for application as a material for manufacturing the arc box of a direct-current low-voltage circuit breaker - Google Patents

Abstract

This invention relates to an arc box material of a direct-current low-voltage circuit breaker, which includes the components in percentage by weight: 45% to 49.5% of aerogenesis polymer, 17.5% to 22.5% of heat absorption metal oxide, 2.5% of smoke suppression synergist, 15% of thermal conductive filler, 15% of reinforcing filler and 0.5% to 1% of coupling agent. The arc box material of the direct-current low-voltage circuit breaker of this invention can be compounded by the aforementioned materials to effectively reduce the phenomenon of thermal dissociation, so that destruction of a mechanism caused by arc light is reduced, and a specific insulation property is kept, providing a material that is suitable for manufacturing the arc box of a direct-current low-voltage circuit breaker.

Description

Arc insulation frame material of DC low voltage circuit breaker

The present invention relates to a DC low-voltage circuit breaker, in particular to a material of the arc insulation frame of the DC low-voltage circuit breaker.

Circuit breaker is an important component for protecting electrical appliances. High-voltage circuit breakers such as gas circuit breakers and vacuum circuit breakers, and low-voltage circuit breakers such as no-fuse switches. When the circuit breaker detects problems such as short circuit, leakage, and severe overload, the circuit breaker will overload and trip, that is, from the on-off state to the open state to protect the circuit to avoid more serious accidents. The function of the circuit breaker is to cut off the circuit under short-circuit or overload conditions to protect the electrical appliances at the power end. Therefore, the effective breaking and high breaking capacity are the performance indicators of the circuit breaker.

The current alternating current (AC) mainstream arc extinguishing methods are: hard drawn arc (speed drawn arc, elongated arc), insulating material gas generation arc extinguishing... and other arc extinguishing methods. Directly applied to DC low-voltage circuit breakers, because the current has no zero point and the arc energy is relatively high, the arc extinguishing test with the same breaking capacity is prone to failure or reignition of the arc. The electrical life and insulation voltage failure after the circuit breaker is also common. .

The arc is mainly maintained through the phenomenon of thermal isolation, so reducing the phenomenon of thermal isolation can effectively reduce the arc energy and reduce the damage to the mechanism by the arc. However, the thermal conductivity of the gas-producing material of the general arc partition frame is about 0.3~0.4W/m‧K, which is not helpful for the phenomenon of thermal dissociation.

Therefore, traditional DC low-voltage circuit breakers have the following problems:

1. The material principle of the arc insulation frame of the existing AC low-voltage circuit breaker is to generate gas when breaking, and the air pressure in the space increases Accelerate and drive the arc into the arc extinguishing brake plate.

2. The same material is used in DC low-voltage circuit breakers. Because the current does not change with time (no zero point), the arc energy is relatively high. Simply increasing the air pressure in the space and the hard-drawn arc extinguishing method is prone to short-circuit test failures and arcs. The condition of reignition, or the condition of successful start-up but the damage of the electrical life and the failure of the insulation withstand voltage.

Regarding this problem, the industry generally conducts more in-depth research on arc extinguishing materials based on gas driving and elongated arcs. The difference of the present invention is the development of arc extinguishing materials for arc maintenance reasons.

The object of the present invention is to provide an arc-insulating frame material for a DC low-voltage circuit breaker. This composite material can effectively reduce the thermal dissociation phenomenon, reduce the damage to the mechanism by arc light, and maintain certain insulation properties.

Another purpose of the present invention is to pass the direct current (DC) short-circuit test. After the short-circuit, the insulation withstand voltage (1kV) leakage current is greater than 0.5mA, and the electrical life after the short-circuit can be maintained at the same level as the AC low-voltage circuit breaker. For the temperature rise test after the short-circuit There is positive help.

The arc isolation frame material of the DC low-voltage circuit breaker of the present invention includes composition weight percentages: gas-producing polymer 45~49.5%, heat absorption metal oxide 17.5~22.5%, smoke suppression synergist 2.5%, thermal conductive filler 15%, reinforcement Filler 15%, coupling agent 0.5-1%. The arc frame material of the DC low-voltage circuit breaker of the present invention can be mixed with the aforementioned materials, so as to effectively reduce the thermal dissociation phenomenon, reduce the damage to the mechanism by the arc, and maintain a certain insulation characteristic, which is suitable for the arc-insulation frame of the DC low-voltage circuit breaker The production materials.

The gas-generating polymer can be, for example, polyamide, and the endothermic metal oxide can be, for example, Magnesium hydroxide, the smoke suppressant synergist can be, for example, zinc borate, the thermally conductive filler can be, for example, magnesium oxide and/or aluminum oxide, the reinforcing filler can be, for example, glass fiber, and the coupling agent can be, for example, silane coupling agent or maleic anhydride graft polymerization.物 Coupling agent. The polyamide can be, for example, polyamide 66 (PA66).

The manufacturing method of the arc insulation frame material of the DC low-voltage circuit breaker of the present invention includes:

Step 1: Put polyamide 66 (PA66) into a desiccant dryer and dry it at 80°C for 4 hours.

Step 2: Put the thermally conductive filler such as magnesium oxide and/or aluminum oxide, and the reinforcing filler such as glass fiber, together with the coupling agent, into a high-speed mixer, and mix for 20-30 minutes (250-500rpm).

Step 3: Put the thermal conductive filler such as magnesium oxide and the smoke suppressant synergist such as zinc borate into a high-speed mixer and mix for 10-20 minutes (250-500rpm).

Step 4: Add the dried polyamide 66 to the high-shear twin-screw mixer, and set the temperature of the twin-screw mixer to 220-265°C (300 rpm).

Step 5: Add the mixture of step 2 and step 3.

Step 6: After mixing, the strips can be extruded (cannot set pressure), drawn, water-cooled (normal temperature water-cooled), dried (80℃ hot air), and pelletized (3mm) to produce injection-level DC low-voltage circuit breakers. The rubber particles of the arc frame material.

Step 7: Melt the rubber particles to form an arc frame by injection molding.

The advantages of the present invention are:

1. The material helps to pass the direct current (DC) short circuit 25kA/36.5kA test.

2. After a short circuit, the material still retains the insulation properties, and the leakage current is less than 0.5mA when a voltage of 1kV is applied.

3. After a short circuit, the electrical life can be maintained at the same level as the AC low-voltage circuit breaker.

4. The thermal conductivity of the newly developed material is 8-10 times higher than the thermal conductivity of existing materials, which can effectively inhibit the damage of the circuit breaker by the short-circuit arc and also help reduce the use temperature.

The present invention is an arc insulation frame material for a DC low-voltage circuit breaker, which includes composition weight percentage: gas-producing polymer such as polyamide 45~49.5%, endothermic metal oxide such as magnesium hydroxide 17.5~22.5%, and smoke suppression synergistic effect Agents such as zinc borate 2.5%, thermally conductive fillers such as magnesium oxide and/or aluminum oxide 15%, reinforcing fillers such as glass fiber 15%, coupling agent 0.5-1% (adding different proportions according to the following examples). The arc frame material of the DC low-voltage circuit breaker of the present invention can be compounded with the aforementioned materials, so as to effectively reduce the thermal dissociation phenomenon, reduce the damage to the mechanism by the arc, and maintain certain insulation characteristics, which is suitable for application in DC low-voltage circuit breakers. The material for making the arc frame.

The gas-generating polymer can be, for example, polyamide, the endothermic metal oxide can be, for example, magnesium hydroxide (MgOH ₂ ), the smoke suppression synergist can be, for example, zinc borate (ZnB), and the thermally conductive filler can be, for example, magnesium oxide. (MgO) and/or alumina (Al ₂ O ₃ ), reinforcing fillers such as glass fibers, and the coupling agent can be, for example, Silane Coupling Agent or Maleic-Anhydride Grafted Polymer Coupling Agent -Grafted). The polyamide can be, for example, polyamide 66 (PA66).

Among them, the thermally conductive filler is preferably one or two of magnesium oxide and aluminum oxide.

Among them, the reinforcing filler is preferably glass fiber with a diameter of 10-13um and a length of less than 1.5mm.

Among them, the coupling agent is preferably a silane coupling agent or a maleic anhydride graft polymer coupling agent.

The arc insulating frame material of the DC low-voltage circuit breaker of the present invention is applied to a molded-case circuit-breaker. In the present invention, for example, polyamide 66 (PA66) is used as a substrate, and the above-mentioned endothermic metal oxide, smoke suppressant synergist, thermally conductive filler and reinforcing filler are added to form an arc-extinguishing material by coupling, in addition to the gas-generating properties of polymer materials. , And adding reinforced fillers to maintain good mechanical properties and maintain the thermal deformation temperature, and the addition of thermally conductive fillers, water and metal objects increase the thermal conductivity by 8-10 times, so that the arc frame material of the DC low-voltage circuit breaker of the present invention is short-circuited During the test, the arc energy can be effectively suppressed, and the start-off can be completed.

The weight percentages of the following four embodiments are shown in the following table, and these four embodiments are exemplary examples:

The physical property tests for the above four embodiments are as follows:

Condition of test piece adjustment: 23±2℃, relative humidity 50±5%, more than 40 hours

The arc isolation frame made by the above-mentioned Examples 1~4 and the materials commonly used in general AC low-voltage circuit breakers (comparison products 1~2) are used to make the arc isolation frame, and the 25kA short-circuit test is compared. The comparison is as follows:

It can be seen from the above table that the material of the arc isolation frame of the DC low-voltage circuit breaker of the present invention is positively helpful for passing the short-circuit test of the DC low-voltage circuit breaker, and it also maintains good insulation characteristics after the short circuit is measured.

The manufacturing method of the arc insulation frame material of the DC low-voltage circuit breaker of the present invention includes:

Step 1: Put polyamide 66 (PA66) into a desiccant dryer and dry it at 80°C for 4 hours.

Step 2: Put the thermally conductive filler such as magnesium oxide and/or aluminum oxide, and the reinforcing filler such as glass fiber, together with the coupling agent, into a high-speed mixer, and mix for 20-30 minutes (250-500rpm).

Step 3: Put the thermal conductive filler such as magnesium oxide and the smoke suppressant synergist such as zinc borate into a high-speed mixer and mix for 10-20 minutes (250-500rpm).

Step 4: Add the dried polyamide 66 to the high-shear twin-screw mixer, and set the temperature of the twin-screw mixer to 220-265°C (300 rpm).

Step 5: Add the mixture of step 2 and step 3.

Step 6: After mixing, the strips can be extruded (pressure cannot be set), drawn, water-cooled (water-cooled at room temperature), dried (air-dried at 80°C), and pelletized (3mm) to produce injection-level DC low-voltage circuit breakers. The rubber particles of the arc frame material.

Step 7: Melt the rubber particles to form an arc frame by injection molding.

The arc frame material of the DC low-voltage circuit breaker of the present invention uses cooling as the arc extinguishing method. In addition to the polymer gas generation effect, the thermal conductivity of the heat-conducting filler and the heat-absorbing metal oxygen compound is increased to 1.6~3.2W/m‧K, Effectively reduce the temperature of the short-circuit arc and suppress the arc energy.

The advantages of the present invention are:

1. The material helps to pass the direct current (DC) short circuit 25kA/36.5kA test.

2. After a short circuit, the material still retains the insulation properties, and the leakage current is less than 0.5mA when a voltage of 1kV is applied.

3. After a short circuit, the electrical life can be maintained at the same level as the AC low-voltage circuit breaker.

4. The thermal conductivity of the newly developed material is 8-10 times higher than the thermal conductivity of existing materials, which can effectively inhibit the damage of the circuit breaker by the short-circuit arc and also help reduce the use temperature.

Claims (7)

An arc insulation frame material for DC low-voltage circuit breakers, which includes composition weight percentages: gas-producing polymer 45~49.5%, endothermic metal oxide 17.5~22.5%, smoke suppression synergist 2.5%, thermal conductive filler 15%, reinforced filler 15%, 0.5-1% coupling agent, mix the aforementioned materials to obtain the material for the arc insulation frame of the DC low-voltage circuit breaker. The arc insulation frame material of the DC low-voltage circuit breaker described in claim 1, wherein the gas-producing polymer is polyamide, the endothermic metal oxide is magnesium hydroxide, the smoke suppression synergist is zinc borate, and the thermal conductive filler is magnesium oxide and / Or alumina, reinforced filler glass fiber, coupling agent is silane coupling agent or maleic anhydride grafted polymer coupling agent. The arc shielding frame material of the DC low-voltage circuit breaker according to claim 2, wherein the polyamide may be, for example, polyamide 66 (PA66). A manufacturing method of the arc insulation frame material of a DC low-voltage circuit breaker, including the following steps: Put the polyamide into a desiccant dryer and dry it at 80°C for 4 hours; Put the thermally conductive filler and reinforcing filler, together with the coupling agent, into a high-speed mixer, stir and mix for 20-30 minutes (250-300rpm); Put the thermal conductive filler and smoke suppressant synergist into a high-speed mixer and mix for 10-20 minutes (250-300rpm); Add the dried polyamide into the twin-screw mixer, and set the temperature to 220-265°C (300rpm); Add the mixture of step 2 and step 3; After mixing, the strips can be extruded (cannot be set pressure), drawn, water-cooled (water-cooled at room temperature), dried (air-dried at 80°C), and pelletized (3mm) to produce arc insulation for injection-level DC low-voltage circuit breakers. Rubber particles of the frame material; and The melted rubber particles are injection molded into an arc frame. According to claim 4, the method for manufacturing the arc insulation frame material of the DC low-voltage circuit breaker, wherein the polyamide is a polyamide 66 (PA66). The method for manufacturing an arc frame material of a DC low-voltage circuit breaker according to claim 4, wherein the thermally conductive filler is magnesium oxide and/or alumina, the reinforcing filler is a glass fiber, and the coupling agent is a silane The coupling agent or maleic anhydride grafted polymer coupling agent is put into a high-speed mixer and mixed. According to claim 4, the method for manufacturing the arc-insulating frame material of a DC low-voltage circuit breaker, wherein the thermally conductive filler is magnesium monoxide and the smoke suppressant synergist is zinc borate, which is mixed in a high-speed mixer.