Detailed explanation of the types and safety prote

2022-08-04
  • Detail

In the 1960s, with the development of battery manufacturing technology, battery power tools without power cord using nickel cadmium batteries as power supply appeared. But at that time, due to the high price, the development was slow. In the late 1970s, due to the lower battery price and shorter charging time, this kind of electric tool was widely used in Europe, America and Japan. In the 1960s, with the development of battery manufacturing technology, battery power tools without power cord using nickel cadmium batteries as power supply appeared. But at that time, due to the high price, the development was slow. In the late 1970s, due to the lower battery price and shorter charging time, this kind of electric tool was widely used in Europe, America and Japan. Electric tools were originally made of cast iron and then aluminum alloy. In the 1960s, thermoplastic engineering plastics were applied to electric tools and realized the double insulation of electric tools, ensuring the safety of electric tools. Due to the development of electronic technology, electronic speed regulating electric tools also appeared in the 1960s. This kind of electric tool uses thyristor and other components to form an electronic circuit, and adjusts the rotation speed according to the different depth of the switch button, so that the electric tool can adopt different national standards of the Russian Federation (such as different materials, drilling diameter, etc.) according to the inequivalence of the processed object, such as din106:1980 "lime sand brick" German industrial standard and the reference poct379: 1995 "technical conditions for silicate bricks and blocks", Select a different speed

types:

electric tools are mainly divided into metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools. Common electric tools include electric drill, electric grinder, electric wrench and electric screwdriver, electric hammer and impact drill, concrete vibrator and electric planer

① electric drill: the main specifications are 4, 6, 8, 10, 13, 16, 19, 23, 25, 32, 38, 49mm, etc. the number refers to the maximum diameter of the drill bit drilled on the steel with a tensile strength of 390n/mm. For non-ferrous metals, plastics and other materials, the maximum drilling diameter can be 30 ~ 50% larger than the original specification

② electric grinder: a tool for grinding with a grinding wheel or disc. There are direct electric grinder and electric angle grinder

③ electric wrench and electric screwdriver: used for loading and unloading threaded connectors. The transmission mechanism of the electric wrench consists of a planetary gear and a ball screw groove impact mechanism. Specifications include M8, M12, M16, M20, M24, M30, etc. The electric screwdriver adopts jaw clutch transmission mechanism or gear transmission mechanism, with specifications of M1, M2, m3, M4, M6, etc

④ electric hammer and impact drill: used for drilling, slotting and roughening concrete, brick walls and building components. Combined with expansion bolts, the installation speed and quality of various pipelines and machine tools can be improved; The impact principle of electric hammer is that the impact power is generated by the movement of internal piston. The impact principle of impact drill is that the impact power is generated by gear running in, so the impact force of electric hammer is greater

⑤ concrete vibrator: used to tamp the concrete when pouring concrete foundation and reinforced concrete components to eliminate air holes and improve strength. Among them, the high-frequency disturbing force of the electric direct connected vibrator is formed by the rotation of the eccentric block driven by the motor. Denghuirong, general manager of the electric Shandong Haien Power Equipment Co., Ltd., informed that the machine is powered by 150Hz or 200Hz medium frequency power supply

⑥ electric planer: used for planing wood or wood structural parts. It can also be used as a small bench planer when installed on the bench. The cutter shaft of the electric planer is driven by the motor rotating shaft through a belt

safety protection of electric tools:

① safety protection of class I tools:

the tools are equipped with grounding devices, and all or most parts of the insulation structure are basically insulated. If the insulation is damaged, because the accessible metal parts are connected with the protective grounding (see grounding) or protective neutral conductor installed in the fixed line through the grounding device, it will not become a live body, which can prevent the operator from getting an electric shock

② safety protection of class II tools:

the insulation structure of such tools consists of basic insulation and additional insulation, "said wangyuanbing, general manager of jiayitong company, which is composed of double insulation or reinforced insulation. When the basic insulation is damaged, the operator shall be separated from the live body by additional insulation to avoid electric shock. Class II tools must adopt non reconnecting power plugs and are not allowed to be grounded

③ safety protection of class III tools:

these tools are powered by safe voltage power supply. The effective value of no-load voltage between safety voltage guides or between any conductor and the ground shall not exceed 50V; For three-phase power supply, the effective value of no-load voltage between conductor and neutral line shall not exceed 29V. The safety voltage is usually supplied by a safety isolation transformer or a converter with independent windings. Protective grounding devices are not allowed on class III tools

④ suppression of radio interference:

single phase series motor and DC motor with commutator will cause serious electromagnetic interference to TV and radio, so the interference of tilting system to radio shall be considered in the design of electric tools. Measures such as shielding, symmetrical connection of excitation winding, setting of electrical filter and filter connection in delta shape are mainly adopted. If necessary, the two ends of the motor armature can also be connected in series through a small inductance coil

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