Chris -
You seem to have missed my point. The term "dry contact" doesn't say anything about the rating of the contacts used in the circuit. The ratings of the contacts are determined exclusively by the technology used to build them. Matching them to the application to a technology is another issue and was not the question asked by the OP. Using a reed relay on a 1kV circuit would certainly lead to disaster. Using a 120V rated set on contacts on a "dry circuit" might work in an application where a contact closure is all that's needed and better suited parts aren't available. I *am* familiar with mercury wetted relays, and have designed a surge generator using them to save space over air-gap contacts. I also have some surplus mercury wetted relays in my lab that I grabbed to keep them from heading for a landfill (still quite serviceable, BTW). Reed relays also sometimes use mercury wetting to increase their life; tip-type motion sensors and thermostats still use mercury wetting of their contacts as the closure means. I didn't contradict you, Chris, or question your veracity. I only offered up an alternative interpretation of the terms presented and pointed out that these terms may define an application, but don't define a contact rating in an existing circuit, which was a part of the OP question. The only way to know what the contacts are suitable for in the OP's "dry circuit" is to look at the switching device used. Regards, Peter L. Tarver, PE [email protected] > From: Chris Maxwell > Sent: Tuesday, February 24, 2004 5:58 AM > > Peter, > > I beg to differ on one point. >deletia< > I didn't make this one up myself. >deletia< > Having said that, I could understand how you > could probably have never > seen these terms used to characterize the load > capability of a relay. > > From: Peter L. Tarver > Sent: Monday, February 23, 2004 3:25 PM > > The terms including "dry" do not contain any notion of the > switching capability of a set of contacts. > This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
