Hi John S. Yeah sorry about the above. One of those posts I just should have deleted and not sent.
JL said he was making up numbers, which is fine by me, as long as he says he's making up numbers... which he did.
I "make up" numbers too sometimes, trying to estimate some unknown thing. Sometimes it's a good guess.. other times experiment shows that it's totally wrong. (In some ways being wrong is more interesting.)
George H.
Those numbers are perfectly reasonable engineering estimates. Without specifying a lot more (load current/voltage/impedance, MTBF expectation, exact switch part number, environment, all that) there is no exact answer. It might take years of testing many switches to generate an "exact" answer.
Testing parts to destruction is always fun. That lets you calibrate risk.
The same consideration applies when the switch is being closed, due to contact bounce. My experience is that the bounce is > 1ms, rather near
10 ms, but it is dependent on the internal mechanics inside the thing.
Yes, George, I understand. When giving advice, disclaimers are good. I did not read "I just made those up" as a disclaimer. I read it as more of a joke. Perhaps his was a poor choice of words.
Sorry, but I was relatively serious. I've seen the debate about paralleling fuses and the 1.5:1 ratio appears there too. It's a decent guess about current sharing in paralleled ohmic devices.
The OP has found a better switch, so it doesn't matter any more.
Well, not to him anyway. He is not the only lurker, though.
(about "uprating" paralleled switch contacts)
Personally, I read it as both, sorta. First-guess safety factor of 1.5 is a fair rule of thumb with no particular objective backing.
I suppose somebody has a name for rules involving numbers pulled out of one's ass, but I can't think of any that would be executive-safe or document-safe the way "rule of thumb" is.
Mark L. Fergerson
Parallel rating would be X, naturally if same reliability is desired. Running at 2*X will guarantee reduced reliability,to estimated region of 1/4 original (or worse). Why? They do not operate at the same time and in the same manner.
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