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Connect two transformer in parallel?

Hi... I want to know that can we connect two center tap transformers in parallel? both are same rating of 24-0-24v, 5a. I want dual supply (plus, minus 24V) for audio amplifier that I am planning to build.
Can someone explain me all the risks, cautions, etc.?
(I am new in audio amplification circuits)

iceng9 months ago
The ac secondaries of many control transformers are designed to be connected in parallel
for increased current output or in series for increased voltage output.

When you connect windings ( of identical secondaries ) in parallel
YOU MUST PHASE THEM  SAME WAY
That  means the AC voltage sine wave goes high on both coils at the same time !

If you phase them in opposition they will form a very Bad double high current short circuit !!


A good way to phase them if you don't have a scope is to place an incandescent light bulb
between the final connection of two coils being paralleled.
It, the light, should not even glow.

A
SaurIMX (author)  iceng9 months ago
What if i connect them in parallel after rectifying (full wave) both secondary winding individually? I think that's a easy and safe way right?
iceng SaurIMX9 months ago
Yes ...  that  works quite well... You will double up on rectifiers.
In fact if one DC is a bit lower it will come in to use when the
other drops down due to loading..
I call that inherent load sharing.
SaurIMX (author)  iceng9 months ago
Is this ckt right? what rectifiers should i use? where to add filter capacitors?
IMG_20131121_115508.jpg
iceng SaurIMX9 months ago
Yes.  see added components
The bridge is here use any 100v 8A bridge as a minimum.
There are ceramic or film capacitors used to filter the fast voltage transients
that the polarized capacitor are too slow to filter but can affect the audio amp.
2xfmr.jpg
iceng iceng9 months ago
BTW 24VAC is the RMS value of the sine wave
after full rectification the peak of the sine is 1.414 times 24 equals 34VDC
See image note the dashed droop from peak to peak
a ripple of 100Hz if you live at 50 cps or 120Hz if 60 cps.
the next step is to add a dual regulators.
DCsine.png