That new gadget

[OFSO]

Has anyone here noticed that every new gadget that arrives not only has a power-supply-in-plug power supply (let's call it a PSU Plug) , but that a lot of these run quite hot, far hotter I am sure than they used to a few years ago ?

All those PSU Plugs are switch mode supplies now, due to some efficiency drive organised by a commitee somewhere, this means they are now the most likely thing to fail, in the past they were a simple transformer, four diodes and a capacitor, generally lasted the life of the device they were connected too as the manufacturers could not really find any ways of cutting corners to make them cheap.

Yesterday I found an old CPU cooler with fan, and epoxied it onto the PSU Plug feeding 9v to my router (wifi and four ethernet cables) and it now runs quite a bit cooler. Of course the fan required yet another PSU Plug, but that's another story.....

Bit convoluted posting but it's late, however does anyone out there also place a hand on their PSU Plugs and remark how warm they run ?

[taxydual]

And, funny old thing, the majority have got 'Made in China' printed on them. Probably costing 4p to manufacture.

Angry mode on seeing as one of these 'so-called' PSU's burned out last night and stunk Taxydual Towers to high hell.

[onetrack]

OFSO - I guess what you're actually pointing out, is that the latest plug-in AC to DC PSU's now use electronic switching to perform the current conversion, as compared to the old transformer stepdown/rectification setup.

Yes, it's true. In the drive to eliminate cost and weight - electronics, and ever-tinier electronics, now rule the world. Yes, they do seem to run hotter than the old transformer style - but I like the compactness and weight saving for when I'm on the move.

I also like my new handyman inverter welder. The comparison to my old 140amp transformer welder is amazing.
The old welder weighed 50 kgs and I grunted every time I shifted it about. The new inverter welder is 200 amps and weighs 7 kgs.
The inverter welder welds better than the old tranformer welder, with a more stable arc.
Whether the inverter welder lasts 30 yrs like the transformer model - well, that's an unknown.

I never trust any current conversion device - even transformer PSU's can go on the fritz and start a fire.
I have a policy of treating all AC to DC PSU's like 14 yr old daughters - I never leave them unchaperoned.
I switch all my PSU's off when leaving the house, or when I go to bed. I've seen too many house fires where a small plug-in PSU was the suspected cause of the fire.

[OFSO]

If I unplugged and reinserted all the PSU plugs every time I left and departed I would be doing nothing else. The following are all powered by
external PSU Plugs


WiMax
WiFi
CAT Distribution Amplifier
Two printers
Phone/Fax
Internet phone (loses stored numbers when unplugged)
CCTV for house
Antenna Rotator
Two satellite receivers with external PSU Plugs

Two modulators feeding satellite TV into common RF distribution

One flatscreen TV with external PSU Plug
Laptop
Roberts Internet Radio
Wireless headphones
Bluetooth interface to hifi
Powered loudspeakers
Oh and three mobile phones and a tablet, not all of which are plugged in all the time.


Voltages range from 5v to 12v, nearly all DC or pseudo DC.

Yes I am worried about overheating, yes I am aware of the risk, yes I put my hand on each of them at least once a day, and yes I have smoke detectors in the appropriate places. And yes it is a PITA.

[The Flying Pram]

While running hot is clearly not conducive to a long life, neither is constantly plugging in /unplugging. Because all Switch Mode PSU's rectify the AC mains, and then apply it to a smoothing capacitor, there can be considerable surge currents at the moment they are connected to the supply. How big these currents are depends on the exact point in the AC cycle that "hits" those input stages, and is something the user has no control over. Even if you are lucky, and the moment of connection happens to coincide with the crossover point of the sine wave, the first couple of cycles still have to charge the capacitor up to working voltage. Blown diodes are a regular failure mode, or if you're really unlucky the capacitor itself might go :eek:

This also applies to those "Eco Friendly" Compact Fluorescent lamps that the EU are forcing on us. I once read a very in-depth article from an Australian blog, showing some which literally "blew up", and in a few cases actually caught fire.

The only way round this is to employ some sort of current limiting device between the mains and the PSU - this could be as crude as a variable resistor, or on more sophisticated equipment a "Zero Volt" switching circuit. But these all cost more, and the first case requires manual input. No guesses which applies to your "4p" Chinese made PSU!

I suppose you make a case for new homes to have dedicated circuits, purely to power all such chargers and PSU's, which could be fed by a (remotely controlled?) Zero Volt supply. This would greatly reduce the risk of a sudden failure and possible fire, but would anyone be prepared to pay?

[OFSO]

those "Eco Friendly" Compact Fluorescent lamps that the EU are forcing on us.

Mine have all been replaced by LED GU-10 bulbs (very cheap to buy in France BTW).. The "50 watt equivalent" ones which consume about 5 watts are as brilliant as I need and run only slightly warm to the touch.

The ECO friendly bulbs have been retired to my spares box.