Re: [CAD_CAM_EDM_DRO] Center tapped transformer

Tim Goldstein wrote:

>I have a transformer that is center tapped on the secondary. Voltage
>from the center tap to either end is 30 v. from end to end it is 60
>volts. I know that if I want 60 volts I just connect the ends to the
>bridge and tape off the center tap. How do I connect it if I want 30
>volts at the maximum amperage possible? I realize I can connect from one
>end to the center and get the 30 volts, but it seems like I am missing
>out on amperage by not somehow using the other half of the coil.
>
>

You don't get 30 or 60 volts from this, unless it is a resistive
application, and you use no capacitors
in the power supply. You get either 60 x 1.414 from the full windong,
or 30 x 1.414 for the
half-winding. That will be 84.8 for the full winding, 42.4 for half.

What you do for the lower voltage is to use only HALF of the bridge.
Say, you connect the
center tap as the - terminal. Connect both winding ends to the AC (~)
terminals of the
bridge. Connect the + terminal of the bridge to the capacitor's +
terminal. Don't bother
with the bridge's - terminal, unless you have a need for a - 42 V
supply, which you get
essentially free. You can also use two single rectifier diodes on heat
sinks instead of
a packaged bridge.

Jon