Re: Transformers for CNC power supply and connections

Yes you can wire transformers in series.

But, if the wires are not color coded, you might have a
50/50 chance of getting it wrong.

Wire the primaries in parallel and wire the secondaries in series.
Measure your voltage.
If it's about 48 Volts (Two 24 Volt transformers), your OK.
If it measures 0 Volts or some low value, you need to swap
either the primary or secondary winding on one of them.
[ Always a good test ]
I have seen new units with incorrect color codes.

If your buying the transformers new... It would be best just
to purchase one transformer the correct size. (cheaper)

You are correct about series doubles the voltage and parallel doubles
the current. Paralleling however should be done with matched
transformers (else circulating currents).

Matching is not all that necessary when series connected. Example...
One 24Volt/10 Amp in series with a 12Volt/12 Amp will produce
36 Volts at 10 Amps. (Use the lower current rating)

Wire your transformer in series with your EE friend and see if he
lights up.

Tom M.


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "fozzyber <jerry@o...>"
<jerry@o...> wrote:

> Well I type a big long post and it looks like yahoo eat it so here

it

> is again.
>
> I need to make a power supply I would like an out put of50Vdc - 80

Vdc

> and 8-15 amps.
> Someone on this list e-mailed me and said to wire 2 of these in
> series:
> http://www.mpja.com/product.asp?product=7846+TR
> 24Vac 10 amps. in series that would be 48Vac * 1.414 =67.8 Vdc.
> A EE student I work with told me I could not wire transformers in
> series. (but I don't think he is correct or very bright)
> Can I wire the outputs of transformers in series to double the
> voltage? Can I run them in Parallel to double their amprage?
> If so I should be able to buy 4 of these 25V / 7.5 amp transformers.
> http://www.sciplus.com/singleItem.cfm?terms=2294&cartLogFrom=Search
> Build 2 sets that are in series, so I would have 2 50Vac 7.5amp
> transformers then wire the 2 sets in Parallel to get 50Vac 15 amps.
> when I rectify that (50Vac * 1.414= 70.7 Vdc @15 amps)
> Is this correct /acceptable?
> I guess it would look like this"
>
> 25V/ac7.5A TF => 25Vac/7.5A TF \
> \
> 50Vac/15amp =>rectofier => 70Vdc@15A
> /
> 25V/ac7.5A TF => 25Vac/7.5A TF /
>
> Jerry