Low power (<3W) 230VAC to 24VDC converter?

lørdag den 29. oktober 2022 kl. 20.05.31 UTC+2 skrev Robert Latest:

Try Mouser for AC Input Power Module

Do you a favour and use a exernal wall wart. No need for yoor PCB to follow the needed security rules and checks

It is a cool idea, to get a little DC to let one start up a big box with small cold switches or a little management cpu or something.

That shouldn't be a big deal to add a module. I believe there is a spacing which should be easy to implement. Are you talking about some paperwork that is needed?

UL, CSA, CE to start the list of approvals needed if you plan to market this as a product.

If for single one-off use, then other than personal risk, you are on your own recognizance for electrical and fire safety inspections.

John :-#)#

So you are saying the issue is the paperwork... You can use a power module that is already approved and contains the power cord connector, so there are no high voltages running around on your board, so nothing to get approved.

Much like buying a radio module to circumvent many FCC approvals.

On a sunny day (Sat, 29 Oct 2022 23:04:10 -0700 (PDT)) it happened Ricky snipped-for-privacy@gmail.com wrote in snipped-for-privacy@googlegroups.com:

Wonder how that will go with the new USB connector power specs in Europe Will there still be wallwarts with the round connectors? So then you need an USB chip to negotiate a voltage...

Robert Latest wrote: ================

** If you only need a few, get some 24V SMPS type AC adaptors and remove the PCB.

Attach same to your PCB.

.....Phil

Exactly what I was looking for, thanks!

There is. I'm reviving an ancient hobby project of mine that died after many years of constantly driving a minute-pulse normal clock. I wanted to replace the transformer/linear regulator by something more efficient, but this thing uses mains frequency as time normal which isn't supplied by the wall wart. I thought of the wall wart but then I'd have to redesign for quartz or so.

there used to be quite a few AC wall warts, common for modems to generate +/-12V from 12VAC

Perhaps you are not aware that many locations have stopped aligning the AC frequency with real time. It was not a fun thing to try to maintain long term and the need for that sort of accuracy has dropped off hugely with most clocks being quartz crystal controlled and battery powered.

I recall probing a $15 analog quartz clock once and found they pulse the "motor" twice a second, or maybe I should say they double pulse it once a second. The drive pulses power into the coil which makes the magnet rotor turn almost 180 degrees. There are notches in the pole pieces that then make the rotor move the final part of the 180 degrees. The electronics then quickly pulses it again with reversed polarity, completing the 360 degree turn when the rotor aligns with the notches again. I don't recall how close together the two pulses are, but they are quick enough, you almost don't notice it's two rather than just one pulse.

Anyway, my point is you can easily get a 1 second pulse from a $1 quartz clock movement which can be divided down for your 1 minute pulse, if that is what the "minute-pulse" clock needs. Does the minute-pulse clock have a similar Lavet-type stepping motor as the quartz analog clocks? It would be a very simple matter to divide the second tick down to a minute tick and drive the coil of a Lavet-type stepping motor once a minute.

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** Huh ?? Where ?

See

" In the United States, the Federal Energy Regulatory Commission made time error correction mandatory in 2009. "

** But not with common items like microwave and other kitchen ovens.

Battery powered quartz clocks and watches not accurate.

..... Phil