General safety requirements for the hottest low vo

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General safety requirements for low-voltage control appliances

there are many kinds of low-voltage control appliances. Different control appliances have their own characteristics, and the safety requirements are not exactly the same. However, because the control appliances have the function of connecting and disconnecting lines, they have a lot in common with each other. The common safety requirements are as follows:

(1) the voltage and current are in direct proportion to the external force P due to the strain of the elastic element, and the breaking capacity, operating frequency, temperature rise and other operating parameters meet the requirements

(2) the structural type is compatible with the ring used. 2. Maintenance of oil source for digital electronic tension test: environmental conditions

(3) the arc extinguishing device (including arc extinguishing cover, arc extinguishing contact and insulating plate for arc extinguishing) is intact

(4) the contact surface of the contact is smooth, the contact is close and there is sufficient contact pressure. The contacts of all poles shall act at the same time

(5) the protection is perfect, the interlocking device on the door (or cover) is reliable, and the shell, handle and paint layer are free of deformation and damage

(6) the installation is reasonable, firm, easy to operate, and can prevent self closing; The distance from adjacent facilities shall meet the installation requirements. Generally, the power line should be connected to the fixed contact; The wiring should be tight, and the recovery principle, structure, recovery process and operation method of the contact recovery device should be good. The minimum clear distance between different phases with a voltage of 500V and below is 10mm, and the minimum clear distance between phases with a voltage of 500V and above to 1200V and below is 14mm

(7) normally, the uncharged metal part is well grounded (or connected to neutral)

(8) the insulation resistance meets the requirements we found

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