Re: [CAD_CAM_EDM_DRO] current rating of transformers

turbulatordude wrote:

>Hi,
>
>If I have a 24 volt, (12V-0-12) center tap transformer like the MPJA
>unit.
>http://www.mpja.com/productview.asp?product=7846+TR
>
>And isolate the center tap I get 24 volts.
>
>But when rectified, doesn't the current change also ?
>
>There is a note in the catalogue that for this wiring the amps are
>1.8x
>
>The catalogue refers to required ouput amps
>
>
>full wave bridge cap input filter 1.8x to required output amps
>full wave choke input filter = required output amps
>full wave, center tap, cap = 1.2x roa
>full wave, center tap, choke = 0.7x roa
>
>

Using the full winding means current flows in both ends of the winding
all the time. So, the current rating must go down. With full-wave
center tap, each half of the winding gets a rest 50% of the time, so
current rating goes up. I guess what they are saying here is that you
take the load current and multiply by these factors to get the rating
of the transformer.

Jon