1. What is the main difference in construction between older surge arresters and metal oxide surge arresters? Your Answer: Metal oxide arresters have a resistive component, while older surge arresters are purely capacitive.
Correct Answer: Metal oxide arresters contain blocks of zinc oxide and air gaps, while older arresters consist of silicon carbide resistor blocks.
Help: Surge Arresters Applications and Testing
Actually, I’d say that the link is wrong too. Metal oxide surge arrestors can be gapless, or they can have gaps. Just google gapped MOV arresters and you’ll get lots of results for how they are designed, why you might prefer them to gapless arresters, etc. That said, I have no idea how common they are, because I’m pretty sure all the MOV arresters I’ve tested have been gapless.
Same things have happened to me. Sometimes test guys gets it wrong. There is a way to tell them about it and they will review it but I have never done it so I can’t be of help there.
Most everything I have read on the site is great but there are totally quit a few errors.