Electric Encyclopedia: Anti-time over-current relay structure and appearance of what are the requirements?

Anti-time over-current relay structure and appearance of what are the requirements?
1, All parts of the relay should be installed on a fixed, moisture-proof base, and shell protection from external mechanical effects and external objects. The housing should be dust-proof, without opening the case, can observe the action indicator and setting value.
2, the relay should be sealable settings, only open the shell after opening can be adjusted or set. Relay adjusted factory, the relevant parts should be painted.
3, the same type of relay shape and structure installation dimensions should be uniform, should ensure that the fragile parts interchangeability.
4, the relay metal parts should not have corrosion, insulation parts should not be cracked blocks, the material used should not cause contact and other parts of the oxidation and surface damage.
5, on the mechanical action position indicator, the instructions should be able to clearly characterize the action position, without opening the case to restore. For the light indicator, in the structure should provide the convenience of replacement and inspection.
6, all tin welding should be solid and reliable, no virtual welding, and does not allow corrosion of the connecting components. All parts of the relay mechanical or electrical connections should be solid and reliable, not easy to loose.
7, the relay is protruding after the screen is installed wiring, the length of its wiring screw should be considered to install the relay panel thickness, thickness of the metal screen by 5mm calculation.
8, the relay setting mechanism should have a brake or locking device.
9, the relay used by the electronic components should meet the requirements of the appropriate technical standards. Static relay should be installed to check the main part of the level of the test terminal (or hole).
10, printed circuit components installed design should be consistent with GB1360-78 "printed circuit grid" requirement, printed circuit board quality should be consistent with the technical requirements of the printed circuit board.
11, Pluggable structure, the connector should be reliable contact, plug and play, the same type of plug-in relay interchangeable, and should meet the requirements of the appropriate technical standards. The plug-in structure shall not encounter live parts when inserting or withdrawing the plug-in part. Current terminals shall be provided with a reliable setting to prevent overvoltages during disconnection.