Views:0 Author:Site Editor Publish Time: 2019-08-22 Origin:Site
Varistors can be easily used in series. The method is that after the varistor of the two resistor bodies having the same diameter and the same flow rate are connected in series, the varistor voltage is added at the continuous working voltage and the limiting voltage, so that the flow rate index does not change. When it is in the high-voltage power lightning protection needle, it is required to continue working voltage up to thousands of volts, tens of thousands of volts, in fact, is obtained by connecting a plurality of varistor valves in series.
The reason why the varistor is connected in parallel is to reduce the current limit when the peak value of the rush current is reduced under certain conditions to reduce the limiting voltage.
If the varistor obtains a very large flow rate such as 8/20, (50-200) KA, and the varistor voltage is relatively low, for example, less than 200V, the diameter and thickness ratio of the resistor body are far different, in manufacturing There will be difficulties in the process. As the diameter of the resistor increases, the microscopic uniformity of the resistor becomes worse, so the flow rate cannot be increased proportionally with the area of the resistor. It may be a more reasonable method to use a smaller diameter resistor in parallel.
However, due to the high nonlinearity of the varistor, special care must be taken when connecting in parallel. Only after careful pairing, the parameters of the resistor are the same and connected in parallel to ensure uniform distribution of current between the resistors. In addition, several varistors connected in the longitudinal direction can use a pair of varistor with matching parameters, and when the impact is intruded, the voltage difference appearing in the lateral direction can be small. In this case, pairing is also meaningful.