Testing Research On MOV&TMOV Under The Effects Of Temporary Over-Voltage

The essay research on TOV impact on MOV and TMOV which be the core devices of SPD by a large number of testing, analysed the reasons which cause TOV and the damage of TOV, introduce the MOV principle structure. Based on the double Schottky barrier theory, and the effects of the temperature rise of the various points to withstand the power frequency overvoltage MOV, subjected to energy, the MOV in the middle of the temperature rise in the ideal case of large crystal the higher the degree of uniformity of the particle distribution, the better the energy tolerance. SPD vendors to select suitable the MOV and design trip point location reference.The overheating protection devices are being detail comparison and analysis, focusing on proposed TMOV the advantages. According to TMOV works comparative experimental TMOV shell craft, of different manufacturers MOV impact on of security failures TMOV the ability. Found through experiments, the traditional shell process, only the epoxy resin encapsulating the housing MOV in energy dissipation capacity is better to use ultrasonic welding, But large energy frequency voltage and current role, TMOV using ultrasonic welding poured into the quartz sand, shell process, and can not fully guarantee their security failure, as the edge of the MOV anatomical analysis of the reasons for the failure of the breakdown, individual the TCO ceramic shell position breakdown arc directly burned porcelain shell. The quartz sand is wet with epoxy resin to form a deposited TCO porcelain shell around where it can not fully guarantee their safety failure. Producer process and material formulation MOV energy tolerance performance is also inconsistent in TMOV internal chip. Their production process and material formulations are not the same, respectively considerations the MOV and TMOV the security lapse. Experiments show that:the cooling capacity is better, more uniform temperature distribution uniformity MOV energy performance is better tolerated, made TMOV security performance is also good.