Popeye's electronics
Popeye's electronics
(OP)
Well, my customer wants to operate his laboratory equipment in a 'salt-air' environment... for a few hours occasionally'. Eek! Now sales wants to know what it would take to 'harden' the existing design.
It has been a long time since I was involved in harsh environment design. Here are concerns I can think of:
- condensation (leakage currents)
- corrosion (PCB traces)
Above fixed by conformal coating; I expect the power supplies would be the first to go. The fans that are busily cooling the system with all that 'fresh' air might be second.
- connector corrosion
- wire insulation - any degradation
What else are concerns? Can you recommend a good reference for harsh environment design?
Thanks,
John D
It has been a long time since I was involved in harsh environment design. Here are concerns I can think of:
- condensation (leakage currents)
- corrosion (PCB traces)
Above fixed by conformal coating; I expect the power supplies would be the first to go. The fans that are busily cooling the system with all that 'fresh' air might be second.
- connector corrosion
- wire insulation - any degradation
What else are concerns? Can you recommend a good reference for harsh environment design?
Thanks,
John D





RE: Popeye's electronics
RE: Popeye's electronics
We've had thermal control units with fans, and as far as I know, they were never a failure item. With some judicious application of strip heaters, you could minimize exposure to condensation in critical areas.
TTFN
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RE: Popeye's electronics
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If we learn from our mistakes I'm getting a great education!
RE: Popeye's electronics
Unless your insulation is prone to wet-tracking, wiring problems are more likely to come in the shape of degradation of the conductor and of any soldered terminations. All the insulation does most of the time is conceal the damage.
Anything you can do to coalesce the salt mist out of your cooling air before it goes anywhere near the inside of your enclosure is going to pay dividends. Once the salt gets in, it sticks to everything and will continue to rot the electronics every time the air is humid enough to let the salt deposits get damp - even long after the equipment has been removed from the salty environment.
For shipboard equipment that only runs intermittently and is subject to swings in ambient temperature, it's common to fit anti-condensation heaters in the bottom of electronic enclosures. As well as keeping the air inside above its dewpoint, these help keep any salt deposits dry.
A.
RE: Popeye's electronics
The basic way to meet this requirement is to seal the box. If you need cooling, then use a heat exchanger or a sealed heatsink. Using fans would probably add complexity and headaches; better to ban them at the start and avoid the redesign cycles. As already mentioned, use sealed connectors such as 38999-series.
RE: Popeye's electronics
TTFN
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RE: Popeye's electronics
810-F is interesting reading.
John D
RE: Popeye's electronics
I use them in non-ventillated enclosures but they might work in other applications. There are several manufacturers.
RE: Popeye's electronics
John D