Understanding Relay Spec's.

You shame hams everywhere, as it is quite obvious that you are an immature little bastard.

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Geez, Crydom:

http://www.crydom.com/en/index.shtml

Opto22:

http://www.opto22.com/site/solidstaterelays.aspx

Teledyne Relays:

http://www.teledynerelays.com/industrialcommercial.asp

et al:

http://www.google.com/search?q=solid+state+relay&rls=com.microsoft:en-US&ie=UTF-8&oe=UTF-8&startIndex=&startPage=1

are sure going to be sorry to hear that.

"John Fields" John Larkin

** Shame the app notes recommend a * 25 amp rated * SSR be used with a 1/3 HP ( 120VAC) single phase motor.

If the incandescent load is a * single * high powered lamp - similar LARGE de-rating factors apply.

.... Phil

Don't confuse him with numbers. They make him cranky.

John

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Which is precisely why 1 amp triacs aren't generally used in
incandescent lamp dimmers.
 
One would expect that if a mechanical relay has to be derated for use
with inductive or incandescent lamp loads, then the same would hold
true for _any_ switch, with the _amount_ of derating being dependent
upon the type of switch used.

So, since solid-state relays are used routinely for incandescent lamp
and AC motor control,  what do your comments (which seem to be
supporting Larkin's stance) have to do with Larkin's erroneous
assumption that:

"SSRs don't bounce, but an incandescent or motor load will sure kill
them."?

Geez, your very first post to this thread was wrong, stunningly wrong, on electrical fundamentals. So of course you want to engage in endless philosophical wrangling.

Listen: incandescent, motor, and rectifier-capacitor type loads can have huge startup surge currents. That can blow out SSRs and damage relay contacts, and such switch devices are often heavily derated for such loads. That's almost too obvious to state.

And what's erroneous about my last quoted statement? Such loads do kill SSRs. Incandescents are especially interesting since, in addition to startup current surge, they often fail mostly-shorted.

As Phil noted, SSRs have to be hugely derated on current, 10:1 or more, to handle motor switching. Derated on voltage and snubbed and MOVd, usually, too. Turning off can be more interesting than turning on.

What's really tricky is using an SSR or a triac to switch the primary of a power transformer in a rectifier-capacitor power supply. Even more fun is tap switching same.

John

Bikinis? It's 55F here right now. When we see a good-looking woman, we're more likely to say "wow, she looks great in a parka."

John At 10:30 am it's 81* today, but that doesn't matter, the shapely college girls, wear bikinis even when the temp is in the high 60s*. They don't want to waste their time at the beach. Mikek, PCB ambassador

It provides an alternate path for current from an inductive load suppressing a contact damaging arc. Mike

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JF

Ok, read over the app note, I want pick a contact arc suppression RC. On the third page under Capacitor Selection the author seems to arbitrarily pick

15 volts 1 usec. as a "Contact Voltage" for his relay. I don't see where this 15 volts 1 usec came from. I'm using this relay; What would be an approximate "Contact Voltage" to work with? For the calculations can I treat my 1 hp motor as an R of 120v / 7a = 17 ohms. hmm... The more I think about this, the less I think the author had any thoughts about inductive motor loads. Mikek

"John Larkin"

** That can be is rather simple and is used in a few professional audio power amplifiers of up to 500W per channel rating.

I am not referring to so called " soft start " circuits where a resistance limits the magnitude of any inrush surge, but to simply using a hefty triac as the AC power on-of control and a normal switch to operate the triac. The switch is wired in series with a resistor ( say 68-100 ohms) from G1 to gate.

The worst case inrush surge is still within the rating of a low cost 40 amp plastic triac ( eg BTA41-600) and the normal running current such that only a small heatsink is ever needed.

.... Phil

You are full of shit... completely full of shit.

In fact, I think that you are some sub-human shittard species.

You are shit. You are full of yourself. You emit a foul stench.

What more does one need to say about John Larkin? You are full of yourself, and what yourself is comprised of is pure refuse.

Grow the f*ck up, asswipe.

Are you sure that is what takes place?

Wow! You're gonna need lotsa doctors to help relieve you of that feces fetish. You also need to be jailed for stalking.

Are you sure it isn't?

But he was wrong.

John

This group could not care less what you think. Man up nym-nuts and post your real name. Coward.

Ok Glimmerman, Here's your chance to show everyone on the group your vast knowledge.

Answer your question, "What does such a snubber do as the contacts bounce?" Mikek

Ahh, don't waste your time with this yellow coward, he is as pig ignorant as he is chicken. What a waste of skin. Coward.

Don't ask him electronics questions. They upset him no end.

John