Noise meter and grounding issues
Earth and electricity (signal) are inseparable twins. Grounding usually refers to connecting a conductor to the ground. In electronic technology, the ground may not be related to the ground at all, it is only an equipotential surface in the circuit. Like the ground in radios and televisions, it is only a potential reference point in the receiver circuit. Grounding, in power and electronic technology, is both simple, complex, and essential. According to the function of grounding, it can be divided into various types, such as working grounding, protective grounding, overvoltage protection grounding, anti-static grounding, shielding grounding, signal grounding, etc. In radio and television technology, the above types of grounding will be encountered. This article will elaborate on some grounding technology issues based on practical situations.
One. Protective grounding is a protective device set up to prevent insulation damage from causing equipment electrification and endangering personal health. It has two methods: grounding and zero grounding. According to electrical regulations, for systems that use three-phase four wire power supply, due to the grounding of the neutral wire, the neutral wire should be connected to the neutral wire. The metal shell of the equipment should be connected to the neutral wire through a conductor, and direct grounding of the equipment shell is not allowed. This is particularly common in the switchgear in the distribution room of the broadcasting and television system, as well as in power switchgear such as central air conditioners and transmitters, as well as in high power consuming equipment. When planning and designing, the grounding busbar should be introduced from the grounding grid to each equipment, and then the machine casing should be connected to the grounding busbar with conductors. It is worth pointing out that the grounding wire should be connected to the grounding terminal of the equipment, and the other end should be easy to use for welding. Sometimes the equipment casing may feel numb, which is caused by AC leakage and the equipment casing not being connected to zero. Generally, the power plug can be unplugged and replaced before being inserted. In some frequently moving cataloging devices, due to the neglect of the neutral line, some operators may come into contact with both the neutral and non neutral devices, which may lead to the above phenomenon.
II. Overvoltage protection grounding is a grounding protection device set up to prevent lightning. The most widely used lightning protection devices are lightning rods and arresters. The lightning rod enters the ground through iron towers or building steel bars, while the lightning arrester enters the ground through a dedicated ground wire. Lightning arresters must be inspected before the thunderstorm season every year to prevent failure. If the * * telephone access device on our station is struck by lightning, it is due to the failure of the lightning protection device on the telephone line. On the lightning protection down lead, never connect the ground wire of other equipment. The lightning protection down lead can only be directly grounded separately, otherwise lightning will damage other equipment through the down lead. For example, a certain satellite TV receiver has been struck by lightning several times, and the original problem was that the insulation was damaged due to friction between the feeder and the metal guardrail on the roof, and the metal guardrail was welded together with the lightning rod downlead, causing lightning to enter and damage the receiver.
