Re: Toroidal transformer ratings?? What after being rectified?

> Thanks to all who responded. Now, what happens to this amperage

rating after it goes through a rectifier? I know the DC voltage will
increase by a factor of 1.416 due to the RMS. Does the amperage stay
the same or decrease due to the increased voltage?

>
> Ron

In a DC power supply with a fullwave bridge rectifer and capacitor
filtering, the required RMS current rating of the transformer is a
WHOPPING 1.8 X the dc current....

For example, if you want a 80VDC supply at 20 amps you need a
transformer with a rating of 36 amps....

Furthermore the voltage of the transformer secondary would be 80VDC
x .707 = 56.56 volts AC

And, the power rating of the transformer would be 56.6VAC x 36AMPS =
2037.6 watts...or about 2Kw min size...

The only thing we left out is the voltage drop across the bridge
rectifer, about 1.4 volts...If this bothers you add it to the 56.56
volts of the transformer to make up for it....However this power
supply because it is unregulated will drift around a lot more than a
couple of volts....



Wally







--- In CAD_CAM_EDM_DRO@yahoogroups.com, R Rogers <rogersmach@y...>
wrote:

> Thanks to all who responded. Now, what happens to this amperage

rating after it goes through a rectifier? I know the DC voltage will
increase by a factor of 1.416 due to the RMS. Does the amperage stay
the same or decrease due to the increased voltage?

>
> Ron
>
> Les Newell <lesnewell@h...> wrote:
>
> Hi Ron,
>
> KVA = kilo volt amps. Multiply the KVA rating by 1000 then divide

by the

> output voltage to get the current in amps.
>
> Les
>
> R Rogers wrote:
>
> >Looking at toroidal transformers or any transformer, How does one

determine the secondary output amperage? They are generally rated by
voltage and then Kva or Kv. Why dont they say just Voltage and
Amperage?

> >
> >
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