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Electronics => Projects, Designs, and Technical Stuff => Topic started by: andybarrett1 on November 05, 2015, 04:19:48 pm

Title: 230v or 415v AC to 24v PSU
Post by: andybarrett1 on November 05, 2015, 04:19:48 pm
Hi All
Looking for a means of getting a decent 24v DC supply (low current) from 230 or 415AC

Have looked at using X2 cap/resistor/zener option but no isolation from mains which will be needed...

Wondering if can still use this method but then into a switch mode so using the switch mode as isolation ???

Just looking for ideas at moment .... Has to be small and cheap !

All ideas welcome !

Thank you for reading

Andy
Title: Re: 230v or 415v AC to 24v PSU
Post by: Paul Price on November 05, 2015, 06:52:57 pm
The really important question here to offer a solution is for you to reveal what current you call low current?
Title: Re: 230v or 415v AC to 24v PSU
Post by: andybarrett1 on November 05, 2015, 07:01:07 pm

No more than 250mA... Maybe less than that.

A 4-20mA Loop
1 PIC Chip
2 PCB Mounted 5v Relays
3 Leds

As a start point !

TY
Andy
Title: Re: 230v or 415v AC to 24v PSU
Post by: Paul Price on November 05, 2015, 07:08:16 pm
You say the 24V power supply must work also using 415 RMS VAC power line input as well?

Otherwise, a transformer:
 ABL6TS02B
   

SCHNEIDER ELECTRIC

Isolation Transformer, Phaseo Optimum, 25 VA, 1 x 230V, 1 x 400V, 24V secondary
Title: Re: 230v or 415v AC to 24v PSU
Post by: station240 on November 05, 2015, 07:18:55 pm
You can use a Buck/Boost Inverter with a transformer instead of a coil.
That would give you the isolation at the output. Feed the inverter from the X2/resistor/zener supply.

Another option is to rewire/rewind a CCFL inverter that just has a transistor based driver.
Title: Re: 230v or 415v AC to 24v PSU
Post by: andybarrett1 on November 06, 2015, 10:26:00 am
Thanks for replies..

I also have a space constraint....

The board I want to mount this on has a size 90mm x 90mm.... And is already half populated with some logic and relays. I am aware I can use a transformer etc.... But that is not an option hence  thinking about the Capacitor Drop... Not a Transformer !

Station240: Inverter / Buck Boosts are to step up usually ?

BR
Andy