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

Lasse Langwadt Christensen wrote:
> lørdag den 29. oktober 2022 kl. 20.05.31 UTC+2 skrev Robert Latest:
>> Looking for something that solders into a PCB like the ubiquitous cheap
>> DC/DC modules, but AC to DC with galvanic insulation. Couldn't find any but
>> maybe didn't look right.
>
> https://www.digikey.com/en/products/detail/mean-well-usa-inc/IRM-03-24/7704638

Exactly what I was looking for, thanks!

Uwe Bonnes wrote:
> Robert Latest <boblatest@yahoo.com> wrote:
>> Looking for something that solders into a PCB like the ubiquitous cheap DC/DC
>> modules, but AC to DC with galvanic insulation. Couldn't find any but maybe
>> didn't look right.
>
> Do you a favour and use a exernal wall wart. No need for yoor PCB to
> follow the needed security rules and checks 

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.

søndag den 30. oktober 2022 kl. 18.45.38 UTC+1 skrev Robert Latest:
> Uwe Bonnes wrote: 
> > Robert Latest <bobl...@yahoo.com> wrote: 
> >> Looking for something that solders into a PCB like the ubiquitous cheap DC/DC 
> >> modules, but AC to DC with galvanic insulation. Couldn't find any but maybe 
> >> didn't look right. 
> > 
> > Do you a favour and use a exernal wall wart. No need for yoor PCB to 
> > follow the needed security rules and checks
> 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

On Sunday, October 30, 2022 at 1:45:38 PM UTC-4, Robert Latest wrote:
> Uwe Bonnes wrote: 
> > Robert Latest <bobl...@yahoo.com> wrote: 
> >> Looking for something that solders into a PCB like the ubiquitous cheap DC/DC 
> >> modules, but AC to DC with galvanic insulation. Couldn't find any but maybe 
> >> didn't look right. 
> > 
> > Do you a favour and use a exernal wall wart. No need for yoor PCB to 
> > follow the needed security rules and checks
> 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.

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. 

-- 

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

Tricky Ricky wrote:
------------------------------
>
> Perhaps you are not aware that many locations have stopped aligning the AC frequency with real time.

  **   Huh ??   Where ? 

See
https://en.wikipedia.org/wiki/Utility_frequency#Time_error_correction_(TEC)

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

> 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. 

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

Battery powered quartz clocks and watches not accurate.

.....    Phil