Delta Transformer with Taps

[lauraj]

Has anyone ever seen a delta transformer that has center taps on all phases? What would you use this for? How would you hook this up?

I'm familiar with the center-tap delta where one of the phases is center-tapped and grounded, but not this other configuration.

 

[coulter]

Re: Delta Transformer with Taps

Three leads per leg, or four?

I've seen four lead per leg so one can hook up either 240V or 480V - but I'm guessing you already knew that.

The only other thing I can think of is for a zig-zag xfmr grounding connection.

carl

 

[lauraj]

Re: Delta Transformer with Taps

This was actually a picture I saw in a transformer book, but it didn't explain how it was used, just said it could supply 1-phase, 120v.

Each phase of the delta was 240 volts and it showed the center of each phase being tapped, but not grounded.

 

[jtester]

Re: Delta Transformer with Taps

It certainly would work from a theoretical perspective. From the center of each coil to the outside leg would be 120 volts. You would use three 120/240 volt transformers, being sure to unground all, or all but one, and connect the secondaries in a delta.

While it would work, under most cases it would be a violation of 250.20 which requires a system to be grounded if it can be with a maximum of 150 volts to ground or less.

Jim T