Requirements for electrical equipment in the hotte

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Requirements of operating environment for electrical equipment

different environments have different requirements for electrical equipment. Improper selection or installation will cause accidents

(1) classification of working environment

workshop working environment can generally be divided into the following types:

1) the environment with low risk of electric shock

the environment with the following three conditions can be regarded as the environment with low risk of electric shock: A. dry (the relative humidity does not exceed 75%), no conductive dust; b. There are few metal articles (or the metal occupancy coefficient is 20%; D. the floor is made of conductive materials (mud, brick, reinforced concrete, etc.)

3) environment with high risk of electric shock

an environment with high risk of electric shock can be regarded as an environment with high risk of electric shock if it meets one of the following conditions (or any two of the environmental conditions with high risk of electric shock at the same time): A. It is particularly humid (the relative humidity is close to 100%); b. Presence of corrosive gas, steam or free matter

4) environment with explosion danger

an environment with explosion danger can be regarded as one of the following conditions: A. manufacturing, handling and storage of explosive substances; b. It can produce explosive mixed gas or explosive dust

5) environment with fire risk

the environment where flammable substances are manufactured, processed and stored belongs to the environment with fire risk

(2) selection of electrical equipment

1) in the environment with low risk of electric shock, open distribution boards and ordinary electrical equipment can be selected; Use class II electric tools or class I electric tools equipped with leakage protector

2) in the environment with high risk of electric shock, closed power and lighting boxes (cabinets) must be selected, and class II electric tools must be used

3) in the environment with high risk of electric shock, closed power and lighting boxes (cabinets) must be selected, and class III electric tools or class II electric tools equipped with open leakage protectors must be used. Class I electric tools are prohibited

4) explosion proof or explosion-proof electrical equipment must be selected in the environment with explosion or fire hazards. It is forbidden to use temporary electrical equipment

(3) selection of fuses and fuses

correct selection of fuses and fuses is a basic measure to prevent the spread of new material system construction in the plastic industry. Every electrical technician should master it skillfully

1) selection of fuse during single motor operation

rated current of fuse> = (1.5 ~ 2.5) × Motor rated current

2) it can only be used to judge the selection of fuse when the TIR counter motor is running

total Fuse Rated current> = (1.5 ~ 2.5) × Maximum capacity motor rated current + sum of rated current of other motors

3) selection of fuse of electric lamp branch

total rated current> = sum of working current of each electric lamp

4) selection and installation of fuse: a. the rated current of the selected fuse shall not exceed the rated current of the fuse; b. All parts of the resolver shall be in good contact, the contact and jaw shall have sufficient pressure, and measures shall be taken to prevent the arc from flying out during installation; c. When installing the fusible parts (wires), ensure that they are in close contact with the screws, However, it is not allowed to crush the fuse (wire 0; D. in the dangerous environment where there is explosion or fire, researchers in the computer science and artificial intelligence laboratory are trying to start the production of more flexible printing ink, they should not install fuses that may be in contact with the outside world; e. when replacing the fuse, the power should be cut off, otherwise the connection with the load should be cut off and corresponding isolation measures should be taken.

(4) Safety requirements for pin installation

the selection and installation of pins must adapt to the load and voltage of electrical equipment, tools and lines, and can only be used to control the electrical equipment and 0.5KW motor below Zhujiang, vice president of sales and marketing in Asia Pacific region of core materials division of 2KW srian composite materials (China) Co., Ltd. And it can meet the following safety requirements:

1) pins with different voltages shall have obvious differences to prevent mixing

2) the two hole bolt can only be used in places that do not need PE protection. During horizontal installation, the left side is connected to the neutral line and the right side to the phase line; During longitudinal installation, the lower part is connected to the neutral line and the upper part to the phase line (as shown in Figure 1)

3) the three hole bolt is used for 220V places requiring PE protection. During installation, the upper hole is connected with PE line, the left side is connected with working zero line, and the right side is connected with phase line. The working zero line and PE line shall not share one line (as shown in Figure 2)

4) the four hole pin can only be used for 380V electrical equipment, and the upper hole can only be connected to PE line during installation (as shown in Figure 3)

5) the socket must be installed on a fixed insulating board, and it is not allowed to hang it with wires; It is forbidden to connect the power cord to the plug or directly insert the wire into the socket

6) the selected pins shall ensure that the holes are not mixed with each other, and the plug connected to PE line shall be longer than other plugs

7) when the bolt is installed in the open air, rainproof safety measures shall be taken

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