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125A 1P,2P,3P,4P 10KA Minature Circuit Breaker Effective Protection Of Power Lines
Jun 12, 2017

125A 1P,2P,3P,4P 10KA Minature Circuit Breaker In modern life, circuit breaker is a pivotal circuit device, and is one of the most important safety devices in commercial and home circuits. Once the current flow in the house wiring is too large, this simple circuit device will cut off the power supply until the fault is eliminated. Since the reform and opening up, China's household appliances industry has developed rapidly, increasing production and variety, greatly satisfying and enriching the needs of consumers. The circuit breaker has been widely used in low-voltage power distribution system at all levels of feed line, a variety of mechanical equipment, power control and terminal control and protection in the side everywhere visible. With the development of the needs of various industries, circuit breaker in the process of being used, because users do not understand the technical parameters, resulting in the use of electrical appliances should not be due to power outages or the unnecessary disconnection of electrical equipment, reducing the reliability of power supply, resulting in a certain economic losses. The following figure is the C45 structure of the circuit breaker structure, the market still occupies a large market, and the C65 structure and L7 structure is now gradually popular in the market.

1. Working principle

As a kind of switch apparatus not only can connect and break the normal load current and overload current, but also can connect and break short-circuit current. Although there are many kinds of circuit breakers, the basic structure and working principle are basically the same. The driving force of the disconnect contact is very important when the double metal plate is used as a circuit breaker with overload current. When the overload current occurs in the circuit, when the bimetal sheet heats up to a certain degree, it will push the traction lever, causing the transmission of the operating mechanism and the contact head to disconnect. When the short circuit instantaneous current, the current reaches the rated current dozens of times times, then the circuit breaker electromagnetic tripping device will move quickly, pushing the traction rod, causing the operation mechanism of the transmission, contact disconnect. In the life of the 125A 1P,2P,3P,4P 10KA Minature Circuit Breaker to take off, basically rely on the bimetal sheet heating bending to induce circuit breaker off.

2. Failure analysis

125A 1P,2P,3P,4P 10KA Minature Circuit Breaker in commercial, household normal use process, due to the use of large electrical equipment at the same time, resulting in the circuit breaker load end of the actual operating current is greater than the selected circuit breaker rated current, and in the continuous use of multiple hours, the resulting load current will be a few times the rated current, will make the circuit breaker off. In the national standard GB10963.1-2005, the time-action characteristics of the circuit breaker are specified, as shown in the table. These characteristics can be in the Low-voltage power supply line in the event of overload or short circuit failures, in the power supply line to protect the circuit breaker will act, so that the circuit is cut off to protect the power supply line, power equipment not due to overload or short-circuit, such as failure to burn. It can be seen from the table that when the current in the actual circuit reaches a certain value, the circuit breaker will be deducted in the specified time range, which effectively protects the power supply line.

In addition to the impact of the current on the load end, the temperature rise is also an important indicator of the performance of the circuit breaker. In the electrical work in the AC circuit, due to the role of alternating electromagnetic field, but also in the ferromagnetic body generated eddy current and hysteresis loss, and in the insulation of the body to produce dielectric loss. All of these losses are almost completely converted into heat energy, some of which are lost to the surrounding medium, and some of them heat the electrical apparatus to raise its temperature. If the 125A 1P,2P,3P,4P 10KA Minature Circuit Breaker wiring end wire is not connected and long-term use process, because the contact area of the wiring end is reduced, and the contact resistance will increase, the current will be smaller, so that the circuit breaker terminal temperature rise too fast. When the temperature exceeds a certain range, its mechanical strength and insulation strength will be significantly reduced. Lead to reduced service life, affecting the normal operation of electrical appliances. In reality, there will also be the use of poor quality of the wire, or the installation is not in place and so on, resulting in temperature rise makes the circuit breaker trip. Taking copper as an example, the softening temperature of copper is about 100 during continuous heating, and the softening temperature of copper is increased to about 300 Shan in the short time of heating. The limit allowable temperature of bare conductor in electrical apparatus should be less than the softening point of material.

In order to ensure the reliability and service life of the electrical work, in the GB 10963.1-2005 standard, the 125A 1P,2P,3P,4P 10KA Minature Circuit Breaker in ambient air temperature is not more than 40 Shan, and the average temperature within the Shan is not more than 35, the wiring terminal connecting the external conductor allows the temperature to rise to the K. When the temperature rise exceeds the allowable temperature rise certain value, the circuit breaker will push its bimetal sheet to bend, causes the product to pull off, thus affects the normal work. Therefore, temperature rise is also as an important index for the reliability and safety of the circuit breaker.

3. Selection

Through the above analysis, when the circuit breaker is installed, it can be selected according to the following conditions: the rated current is greater than the actual working current in the load, the rated voltage is greater than the rated voltage of the power supply and the load; The three aspects of the circuit breaker and the matching traverse area will reduce the indirect tripping of circuit breakers during commercial and household u