1、Application type of ZOV Varistor
For different applications, the purpose of applying a zov varistor should be that the voltage/current applied to the zov varistor should be different.
Therefore, the requirements for zov varistor are also different. It is important to distinguish this difference for proper use.
The zov varistor can be divided into two categories depending on the purpose of use:
① protection zov varistor
② circuit function zov varistor
2、Type of varistor
①Surge suppression type: refers to a varistor used to suppress transient overvoltages such as lightning overvoltage and operating overvoltage. The occurrence of transient overvoltage is random, non-periodic, and the peak value of current and voltage may be very high. Big. Most varistors fall into this category.
②High-power type: refers to the varistor used to absorb the continuous pulse group appearing in the cycle, for example, the varistor connected to the switching power converter, where the impulse voltage cycle occurs, and the period is known, the energy value can generally be calculated. When it comes out, the peak value of the voltage is not large, but because of the high frequency, the average power is quite large.
③High-energy type: refers to a varistor that absorbs magnetic energy in a large inductive coil such as a generator excitation coil and a lifting electromagnet coil. For such applications, the main technical indicator is energy absorption capability.
The protection function of the varistor can be repeated many times in most applications, but it is sometimes made into a "one-off" protection device like a current fuse. For example, a short-circuit contact varistor connected in parallel to some current transformer load.