Dual Power Supply without centre tapping..

[Rajagopal87]

Here is my problem:
I need 36 volt dual power supply (+36, -36, GND) for my newly constructed audio amplifier to work. I am already having the following transformers. Is there any way to build the power supply without buying a new transformer?

0-32 volt 4 Amp max. ----no center tapping.
12-0-12 5 Amp max ----with centre tapping
12-0-12 5 Amp max ----with centre tapping

If there was a center tapping I guess my job would go very easy. But without the center tapping I fear that I can make only ~ +/- 16 v power supplies. Is there any other way?

 

[Nigel Goodwin]

Use BOTH 12-0-12 transformers connected to give 24-0-24, that will give you fairly close to +/-36V DC.

 

[Rajagopal87]

How To Connect....

Can you please explain how to connect them?

I am sure it is not parallel connection ( as we will end up with 12v again ).
Of the three leads in the secondary of each transformer only the centre tap could be distinguished. The remaining two are identical. I guess that the voltages in the two leads are 180 degree out of phase(am I right?) How to obtain 24-0-24 from the six leads? How should I distinguish the leads of same phase and opposite phase? Will it matter when connecting them?

 

[ljcox]

Can you please explain how to connect them?

I am sure it is not parallel connection ( as we will end up with 12v again ).
Of the three leads in the secondary of each transformer only the centre tap could be distinguished. The remaining two are identical. I guess that the voltages in the two leads are 180 degree out of phase(am I right?) How to obtain 24-0-24 from the six leads? How should I distinguish the leads of same phase and opposite phase? Will it matter when connecting them?

Call the leads 1, 2 & 3 on transformer A and 4, 5 & 6 on transformer B where 2 and 5 are the centre taps.

Join 3 & 4 and measure the voltage between 1 & 6. If you have (by chance) chosen the right combination, then the voltage will be 48 Volt or greater. If you only read a small voltage, then join 3 to 6 and measure between 1 & 4.

Regarding your question re "voltages in the two leads are 180 degree out of phase(am I right?)" the answer is yes. If you use say lead 2 as the common, then the phase difference between voltage at 1 and 3 is 180 degrees. That is why you there is 24 Volt between 1 & 3.

 

[Rajagopal87]

Thank You

Thank You Nigel and ljcox.
I ll try that.