Varistor Requirements?

Thread Starter

bogey912

Joined Oct 16, 2016
32
Hi folks, great board here. I have a couple of varistors that blew. The one next to the blown ones says S14 , K130 , 0009. During some googling, I found that the 14 is the diameter of the varistor in mm and the 130 is its voltage rating. I have found some varistors on Ebay that say 14mm 680volts. My first question is it alright to use a varistors with a higher rating than the old one. I'm assuming the diameter is not as critical (if it fits) as the voltage rating?
Also what is the best way to test a varistor? Can I do it in circuit? I have a 500vdc megger. would that help? Thank You for your time!
 

Thread Starter

bogey912

Joined Oct 16, 2016
32
Opps, I forgot the second part of my question.
"Also what is the best way to test a varistor? Can I do it in circuit?" Can you tell me this? Thanks!
 
It basically looks like a back to back Zener diode with high short term surge capability. Usually, they visibly self-destruct. A curve-tracer or I-V curve would be a basic test.
 

Thread Starter

bogey912

Joined Oct 16, 2016
32
So from your guy's comments, their is no "easy" way to test a varistor (like with a dmm). If they are not blown, its safe to assume they are ok I guess. Thanks again.
 
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