Transformer Center Tap

[dswiston]

Alright. My first post seems to have not made it onto the board so I'll try this again.

I got a Basler transformer from apexjr.com and forgot to make sure it was center tapped. Well its not, so the only way I can think of making a center tap is to wire up the dual 50v outputs in series. This however gives me a 50-0-50 transformer and at the caps the voltage is +-70v. Now for the project I am working on (Rod Elliots new mosfet amp) the specs for the high power version state +-70v is the safe max for the high power version, however I am building the lower power version and he reccomends nothing more than +-56v. So I was wondering if anyone knew of an easy or simple method to drop the voltage off the 50-0-50 or if I would somehow make my own center tap using some resistors going from each terminal to ground (earth ground). I figured someone in here has probably had the same problem or rather, worked around it.

Thanks guys, lemme know what you think.

BTW, transformer has dual 50v taps, and 6,12,24v taps. They are all isolated and only the 50v taps look "beefy" meaning the current draw possible from the other taps wouldn't suffice for my project.

 

[Centauri]

By 'taps' I assume you mean separate 'windings'?

If the 24V winding is fully isolated, then providing the insulation is good enough, it could be connected in series with, and in phase with, the mains input winding. This will give you a transformer with mains input effectivly 24V higher than actual, resulting in lower output voltages - you could then run your 50V windings in series as you suggested, but with lower output voltage. For this to work, the 24V winding will need to have at least the current capabilty of the mains input winding.

Also, what is your mains voltage? and does the transformer have split mains input windings? (ie 2x120V for 120V or 240V operation)

Cheers

 

[dswiston]

Thanks for the reply. By taps I do mean seperate windings (infinite resistance between the windings according to the ohm meter). The transformer does not have dual input windings. I live in the US so my mains voltage is 120V.

I'm not sure about the current capability of the 24V line. The wire is physically smaller than the mains input wire but I guess its worth a shot. Otherwise I have a heavy paperweight anyway.

Thanks, I'll try it out.