PRO-APEX Electronics Co.,Ltd

 

Field of application (example)

 

Electric welding machine, industrial motor, soft starter, communication base station PCB board, PLC, frequency converter...

 

 

A.Tips: The varistor has an inflection point in the pre-breakdown region of its characteristic curve, which corresponds to a specific set of inflection point voltage and current; when the applied voltage is higher than the inflection point voltage, the varistor will enter The "on" state (the resistance value becomes smaller); when the applied voltage is lower than the inflection point voltage, the varistor enters the "off" state (the resistance value becomes larger). The knee voltage can therefore be understood as the varistor voltage UN (critical voltage between on and off states).

 

B.So：Urms≦(UN×90%)/√2≈0.64U_N

 

C.Special Reminder：

â‘ . If your country has frequent thunderstorms, please increase Urms by 10%

â‘¡. If the quality of your national grid is low (for example, there are many small hydropower stations), please increase Urms by 10%

â‘¢. If both of the above situations exist, please increase by 15%

â‘£. If you use low-voltage power distribution cabinets, you also need to consider the harmonic interference of your country's power system. In this case, it needs to be increased by at least 5%.

 

 

 

A.The principle of determining UDC is: the power consumption of the varistor under the action of UDC is roughly equal to or slightly smaller than the power consumption of the varistor under the action of Urms.

 

B. Conversion formula: UDC≈1.3Urms or UDC≈0.83UN

 

 

Please tell us your field of application, we will help you choose. We will provide you with the most suitable products according to your application field.

 

Tips:Don't buy the most expensive, only buy the right one.

 

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