Re: 3 Isolated AC Outputs from 1 AC Source

On Fri, 12 Jan 2007 15:03:36 +1100, "Phil Allison" <philallison@xxxxxxxxxx> wrote:


<jeff1981@xxxxxxxxxxxxxx> wrote in message
news:1168573684.730487.259510@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx


** Groper Alert !!


I have a single power supply creating between 0 and 90V AC (Adjustable
in roughly 1V increments). I need to 'split' this current source into
THREE completely isolated AC Power Sources which are of equal voltage
to the input current (1:1).

My thought is three simple transformers with 1:1 windings. All the
primary sides connected to the 0-90V Supply which would give me 3
isolated 0-90V Secondaries.

I only need about 20mA on each of the three outputs... 25 MAX.

So, My two questions...
1. Is this an appropriate solution to my problem?
and
2. Can anyone reccomend a small transformer (PCB Mount) that could
handle the task? I've searched a bit on Digi-Key and Mouser, but
frankly, I'm not even exactly sure what I'm looking for so its' a bit
hard to find.



** Small PCB transformers have poor "regulation" - ie the output voltage
varies with load current by up to 25% from no load to full load.

Only YOU know what the application requires in the way of "equal"
voltage matching.

I suspect that 1:1 transformers rated at 120 volts AC and only a few VA are
hard to find.

Not really - using each primary of a dual-primary 230/110v transformer would do it, although
winding-to-winding isolation would be less than normal.

.

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