However, the fourth generation products have been launched abroad.
From simple assembly and imitation manufacturing to independent development and design, the low-voltage electrical appliance industry in China has grown to nearly 1 000 series, with about 1 500 manufacturers and an annual output value of about 20 billion RMB.
It is predicted that in 20 10, the first generation products will be eliminated, the second generation products will become low-grade products, and the third generation products will gradually become mid-range products.
While we are speeding up the development of the third generation products and bringing them to the market, some famous foreign low-voltage electrical appliance manufacturers have successively introduced new generation products from the late 1990s to the early 20th century, among which frame circuit breakers include Schneider MT series, Siemens 3WL series, ABB E series, GE M-PACT series and Kyle Magnum series. There are NS series of Schneider Company, 3VL series of Siemens Company, Tmax series of ABB Company, Record plus series of GE Company, NZM series of Moeller Company, G series of Kyle Company and WS series of Mitsubishi Company. In addition to high performance, electronics, intelligence, modularization, combination and miniaturization, the new generation products also have the characteristics of communication, high reliability, good maintenance performance and environmental protection requirements. Especially, the new generation products can be connected with the field bus system, which realizes the networking of the system and makes the function of low-voltage electrical products have a qualitative leap. High performance, high reliability, intelligence, modularization and environmental protection.
High performance. The rated short-circuit breaking capacity and rated short-time withstand current are further improved, and Icu=Ics is realized. For example, the MT series products of Schneider Company have the highest short-circuit breaking capacity in operation, and the limit short-circuit breaking capacity is 150kA.
High reliability. The product not only requires high performance index, but also does not reduce capacity when used, and will not overheat when used at full load for a long time, thus realizing safe operation.
Smart. With the emergence of ASIC and high-performance microprocessor, the circuit breaker has realized the intelligence of the release, greatly strengthened the protection function of the circuit breaker, and can realize the functions of overload long delay, short delay of short circuit, instantaneous short circuit, grounding, undervoltage protection and so on. It can also display system operation parameters such as voltage, current, frequency, active power, reactive power and power factor on the circuit breaker, and can avoid misoperation under the influence of higher harmonics.
Fieldbus technology. The new generation of low-voltage electrical appliances has realized communication and networking, and can be connected with various open field buses for two-way communication, thus realizing the functions of remote control, remote communication, telemetry and remote adjustment of electrical appliances. The application of fieldbus technology can not only monitor the distribution quality, but also reduce the loss. Moreover, fieldbus technology can realize the regional interlocking of multiple circuit breakers in the same regional power grid, realize the automation of distribution protection, and further improve the reliability of distribution system. Profibus, Modbus and DeviceNet are used in the field of industrial field bus, among which Modbus and Profibus have great influence.
Modularization and combination. Combining modules with different functions into modular products according to different requirements is the development direction of new generation products. For example, Tmax series introduced by ABB, thermomagnetic release, electronic release and electronic release can be interchanged. Accessories are modular structure and can be installed without opening the cover.
Use green materials. The selection of product materials, manufacturing process and use process do not pollute the environment, which conforms to the EU environmental protection directive. It aims to improve the technical level of various occupations.
The manufacture of low-voltage electrical products involves many professional processes, such as cold stamping, plastic molding, coil winding, contact welding, mold processing, SMT patch technology and so on. Therefore, the improvement of manufacturing technology of low-voltage electrical products is inseparable from the improvement of these professional processes.
High-speed, automation and specialization of parts processing
Stamping parts account for a large proportion of low-voltage electrical parts, about 70%, so stamping parts processing plays an important role in the production of low-voltage electrical appliances. In order to improve the production efficiency and quality of stamping parts, it is imperative to adopt high-speed automatic punch and multi-station progressive die.
Plastic parts are important parts of low-voltage electrical appliances. Adopt fully automatic or semi-automatic thermoplastic or thermosetting injection molding machine and adopt centralized feeding mode.
Automatic welding machinery is widely used, with adjustable welding current, pressure and pulse period, controllable temperature and guaranteed welding strength. Manual wiring (not relying on models or molds) shall meet the requirements of straightness, neatness, closeness to the laying surface, reasonable wiring and no looseness of contacts, so as to facilitate maintenance.
1. Wiring channels should be as few as possible. Submerged conductors in the same channel shall be classified and concentrated according to the main circuit and control circuit, and arranged or bundled in parallel in a single layer, and shall be close to the laying surface.
2. The length of the conductor should be as short as possible and can be crossed horizontally overhead, such as the connection between the coils of two components and the connection between the main contacts. If a certain margin is left, it may not be close to the paving surface.
3. The wires in the same plane should be highly consistent or consistent and cannot cross. When it is necessary to cross *, it can be crossed horizontally overhead, but it must belong to a reasonable route.
4. The wiring should be horizontal and vertical, and the transformation direction should be 90 vertical.
5. If the upper and lower contacts are not on the same vertical line, diagonal connection should not be adopted.
6. When the wire is connected to the terminal or terminal, the insulation layer shall not be compressed, the loop shall not be reversed, and the copper exposure shall not be greater than 1 mm ... The wire spacing between different contacts of the same component and the same loop shall be consistent.
7. There should be no more than two connecting wires on the terminal of an electrical component, and generally only one connecting wire is allowed on each terminal board.
8. When wiring, it is forbidden to damage the insulation of wire core and wire.
9. When the cross-sectional areas of wires are different, this will put the large cross-sectional area in the lower layer and the small cross-sectional area in the upper layer.
10. When connecting multiple wires (main circuit), the whole wires should be at the same level or
The same vertical plane. 1 1. If the lines are simple, there is no need for coding sets. 1. The protective conductor (PE) must be yellow and green:
2. The middle line (N) and the middle line (M) of the power supply circuit must be light blue:
3. AC or DC power supply circuit should be black:
4. The AC control circuit is red:
5. The 5.DC control circuit is blue:
6. If the wire used for the interlocking control circuit is connected to the external control circuit and the power switch is still live, it should be orange or yellow:
7. The circuit connected to the protection line is white: