How to Wire a Transformer with Two Primary Windings – Step-by-Step Guide

bridge-rectifierrectifiertransformer

I'm building a circuit that involves the use of multiple transformers. I've mainly used transformers that had one primary and one or two secondary windings. However, this time, the transformer I'm working with has two primary windings and two secondary windings, like in the diagram below:

schematic

simulate this circuit – Schematic created using CircuitLab

What is the proper way to wire such a transformer? Do both primary sides have to be wired to something in order to work? In my simulation, I'm only using one primary winding and one secondary as a bridge-rectifier, so the other one is not used at all. If I decide to make S1 and S2 center-tapped, will I have to use P2 as well?

EDIT: More info, I'm working with 115 Vrms. This is a signal transformer. If I have to give it a model, it's the 14A-56-28

Best Answer

First of all your diagram is showing 2 separate transformers. If it is one transformer there should be only one magnetic core like in picture below. There is no 2 primary winding transformer model in CircuitLab. So if you really need it you should create it.
Transformer diagram
A)"What is the proper way to wire such a transformer?"
You can wire in any order. Good practice is to wire all winding in same direction to avoid phase reversal.
B) "If I decide to make S1 and S2 center-tapped, will I have to use P2 as well?"
No. Just leave P2 ends not connected.