A number of years ago, when I was working for the county, I was 'assigned' the electronic up-keep of the jail - which included the ssr controlled electric door latches. Every few weeks, another srr would short; if not disconnected quickly, the solenoid would burn up.
My opinion at the time was 'why ssr's?' Neil - WA6KLA Coy Hilton wrote: > > Here are a few things to remember about Solid State Relays (SSRs). > 1. THEY ARE NOT SAFETY SWITCHES all electronic equipment should have > safety switches to de-energize equipment when it MUST be off for > service. > 2. THEY ARE NOT FUSES that is why you need fuses and breakers. > > Now having said that here are a few more bits of info. I have found > more pitted and fused mechanical relay contacts than I ever have > shorted or overly leaky SSRs. > > Here is another tidbit if you don't beleave in SSRs or are afraid of > them then avoid things like rides at any of your well known > amusement parks and any other large industrial facility. Even in our > small 47 megawatt co-generation plant, SSRs are the norm and not the > exception. > > My point is there is a component that is best for each job and SSRs > are far more reliable overall than mechenical relays, in a lot of > cases. > > AC0Y > > --- In [email protected], "skipp025" <[EMAIL PROTECTED]> > wrote: > > > > You are right on the money Fred... I don't normally > > trust solid state relays to be 100% off at any time. > > > > We've had debates about using them in rf amplifier > > hv supplies over on the below group. > > > > http://groups.yahoo.com/group/rfamplifiers/ > > > > Some people like them, some don't. I don't think > > the leakage issue will be a big problem with the > > standard MSR-2000 power supply. In a large hv > > supply, we use both a hard breaker switch and an > > SSR circuit (with zero cross detection). > > > > In some specialized and vintage audio/rf amplifier > > power supplies I take advantage of the leakage > > to help preform/reform the supply filter capacitors... > > all the time knowing the ssr's are never actually > > off 100%. The "no free lunch" rule always sneaks > > in somewhere... > > > > cheers, > > skipp > > > > > Fred Townsend <[EMAIL PROTECTED]> wrote: > > > There is a characteristic about SSRs that you should be > > > aware of. In the off state a SSR can have a leakage > > > value that can be as low as 100K ohms. That's enough > > > to light a NE2 neon bulb. It's also enough to shock > > > you if you get across an open circuit. Be sure to > > > include a safety switch in series for working on the > > > system. Of course you need a fuse or circuit breaker too. > > > Fred, AE6QL > > > > > > > > Yahoo! Groups Links > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
