TVSS Tester
MOVs degrade with surges or lightning. With Tester you can test to see if you still have surge protection. |
A properly installed TVSS should last for years. However, exceedingly large voltage impulses do take life out of MOV’s. Life reduction can be monitor by noting decreases in the MOV threshold voltage. This can be measured as the DC voltage at 1-mA of DC current. This voltage should never be less than 1.414 x MCOV (maximum continuous operating voltage). When it decreases below this level the applied AC voltage will start to inject current into the MOV causing it to heat up. As it heats up the voltage decreases more causing additional current and heating. This leads to a thermal run-away condition in which the MOV eventually disintegrates or explodes. The 1-mA test measured with Tester makes monitoring of the threshold voltage very easy. |