MOV最大热稳定功频电压Vs的定义和试验方法

贵州飞舸电子有限公司草拟

Parametric terms, letter symbols and definitions

名词术语、表示符号和定义

Maximum thermal stable power frequency voltage VS

最大热稳定功频电压VS

The maximum power frequency voltage across an MOV and the MOV is able to reach thermal stableness (i.e. the increase of temperature less than 2K within 10min.) within 45min.

Note: this parameter is used to determine the power frequency overvoltage withstanding ability of an MOV.

MOV能够在45min内达到热稳定（10min内温升小于2K）所容许施加的最大功频电压。

注：本参数用于确定MOV的功频过电压耐受能力。

Testing and measuring methods

测试方法

Maximum thermal stable power frequency voltage (VS)

最大热稳定功频电压VS

The purpose of this test is to verify the maximum power frequency voltage may be applied across an MOV and the MOV is able to withstand and reach thermal stableness (i.e. the increase of temperature less than 2K within 10min.).In this measurement, a power supply of adjustable voltage source (accuracy grade: 0.5%) and a contact or noncontact surface thermometer should be used.

本试验的目的是为了验证MOV能够达到热稳定(即10min内温升小于2K)可施加的最大功频电压。在本测试中要用到一个精度等级为0.5%的可调电压源、数字式电压表以及一个接触式或非接触式表面测温仪。

测温仪Components

APS Adjustable voltage source 可调电压源

V Digital voltmeter 数字式电压表

The starting point may be from Vr.m.s.=0.75V1mA or any other thermal stableness power frequency voltage, if it is know, and increased 1.0% Vr.m.s. each step. During the test, the surface temperature on the hottest spot of the MOV must be monitored continuously.

功频电压Vr.m.s.的起始值可从0.75 V1mA或者其他任意已知的热稳定电压值开始，每次增加1%。测试过程中要连续监测MOV表面最热点的温度。

This test is interrupted if the MOV is failure or can not reach thermal stableness within 45min. The Vr.m.s. of the last step before being interrupted is the maximum thermal stable power frequency voltage (VS) of the MOV.

如果MOV失效或者在45min内不能达到热稳定，则试验中止；试验中止的前一次所施加的Vr.m.s.即为该MOV的最大热稳定功频电压VS。

Pass criteria

合格判据

The MOV’s VS should not less than the specified value of the manufacturer’s instructions.

MOV的最大热稳定功频电压VS不应低于制造商的产品说明书所声明的数值。