Secondary power lightning protectors, also known as switched lightning protectors, signal lightning protectors and antenna lightning protectors, etc. The function of the secondary power supply lightning protector is to protect electrical equipment from direct and induced lightning.
How to select secondary power supply lightning protector:
1、look at the product model:
There are two main models of two-stage power surge arresters commonly found on the market: one is CWD2 type and the other is CWD1 type. The difference between CWD2 type and CWD1 type is that its internal structure is different.
A. The internal structure of CWD2 type is four-layer and three-terminal (i.e. three-phase and five-stage), and each phase voltage is protected by single-pole or double-pole series connection (single-pole is generally chosen).
B. The CWT1 type has a three-phase, four-stage internal structure, with each phase protected by a multi-pole series connection (generally multi-pole).
2、Look at the appearance of the product:
The appearance of a good secondary power arrester should be smooth and flat, no bubbles, no scratches; shell surface colour uniform; plastic parts shiny colour; gold-plated parts bright luster does not fall off, etc.. Also pay attention to observe whether the product identification content, such as the production plant name and address, etc.
3、Look at the technical performance of the product:
(1) Edge resistance:
The size of the edge resistance directly reflects the performance of the lightning arrester and the length of service life, so we should focus on checking the value of the parameter size and stability and deviation from the nominal value. (In general, more than 1MΩ that is qualified) specific method is to put the meter pen on the three levels or more between the measurement of the resistance value of the size can be judged. (Note: As each product in the factory have been adjusted to the corresponding resistance range).
(2) Frequency withstand voltage:
Frequency withstand voltage refers to the ability of the product to run continuously for a long time at the rated frequency without damage. It includes DC leakage current and impact withstand current two aspects of indicators. (Usually, within 1 minute not more than 5mA for qualified) specific test method is to adjust the tester to the industrial frequency high voltage output gear after the test product to apply the specified test voltage value and maintain a certain time can judge the results.